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II Trial of Gefitinib Given Concurrently With Radiotherapy in Patients With Nonmetastatic Prostate Cancer
Int. J. Radiation Oncology Biol. Phys., Vol. 78, No. 1, pp. 42–49, 2010 Copyright Ó 2010 Elsevier Inc. Printed in the USA. All rights reserved 0360-3016/$–see front matter
doi:10.1016/j.ijrobp.2009.07.1731
CLINICAL INVESTIGATION
Prostate
A PHASE I/II TRIAL OF GEFITINIB GIVEN CONCURRENTLY WITH RADIOTHERAPY IN PATIENTS WITH NONMETASTATIC PROSTATE CANCER GREETTA JOENSUU, B.M.,*y TIMO JOENSUU, M.D., PH.D.,y PETRI NOKISALMI, M.SC., B.M.,*z CHANDANA REDDY, M.SC.,{ JORMA ISOLA, M.D., PH.D.,** MIRJA RUUTU, M.D., PH.D.,x MAURI KOURI, M.D., PH.D.,y PATRICK A. KUPELIAN, M.D.,yy JUHANI COLLAN, M.D.,zz SARI PESONEN, PH.D.,*z AND AKSELI HEMMINKI, M.D., PH.D.*z *Cancer Gene Therapy Group, Molecular Cancer Biology Program and Transplantation Laboratory and Haartman Institute and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland; yInternational Comprehensive Cancer Center Docrates, Helsinki, Finland; zHUSLAB, xDepartment of Urology, Helsinki University Central Hospital, Helsinki, Finland; {Radiation Oncology, Cleveland Clinic, Cleveland, Ohio; **Institute of Medical Technology, University of Tampere, Tampere, Finland; yyDepartment of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, Florida; and zzDepartment of Oncology, Helsinki University Central Hospital, Helsinki, Finland Purpose: To estimate the safety and tolerability of daily administration of 250 mg of gefitinib given concurrently with three-dimensional conformal radiotherapy for patients with nonmetastatic prostate cancer. Methods and Materials: A total of 42 patients with T2–T3N0M0 tumors were treated in a nonrandomized singlecenter study. A prostate-specific antigen (PSA) level of <20 and a good performance status (WHO, 0–1) were required. Adjuvant or neoadjuvant hormone treatments were not allowed. A daily regimen of 250 mg of gefitinib was started 1 week before radiation therapy began and lasted for the duration of radiation therapy. A dose of 50.4 Gy (1.8 Gy/day) was administered to the tumor, prostate, and seminal vesicles, followed by a 22-Gy booster (2 Gy/day) for a total dose of 72.4 Gy. Correlative studies included analysis of epidermal growth factor receptor (EGFR), EGFRvIII, and phosphorylated EGFR in tumors and tumor necrosis factor, interleukin-1a (IL-1a), and IL-6 in serum. Results: Maximum tolerated dose was not reached in phase I (12 patients), and 30 additional patients were treated in phase II. Thirty (71.4%) patients completed trial medication. Dose-limiting toxicities were recorded for 16 (38.1%) patients, the most common of which was a grade 3 to 4 increase in transaminase (6 patients). After a median follow-up of 38 months, there were no deaths due to prostate cancer. The estimated PSA relapse-free survival rate at 4 years (Kaplan-Meier) was 97%, the salvage therapy-free survival rate was 91%, and the overall survival rate was 87%. These figures compared favorably with those of matched patients treated with radiation only at higher doses. Conclusions: The combination of gefitinib and radiation is reasonably well tolerated and has promising activity against nonmetastatic prostate cancer. Ó 2010 Elsevier Inc. Gefitinib, Radiotherapy, Nonmetastatic prostate cancer, EGFR targeted therapy, Chemotherapy.
Prostate cancer is the most commonly diagnosed malignancy and the second leading cause of male cancer death in the Western world. The median 5-year disease-free survival rate for local stage T2 or locally advanced stage T3 prostate cancer patients varies from 30% to 90% in different series. Despite increased awareness and earlier diagnosis, therapy with curative intent seems to fail to achieve long-term cure
in a substantial proportion of patients. Therefore, it is important to identify approaches that can increase cure rates. One promising approach is a combination of radiotherapy and a targeted drug. Preclinical evidence suggests that smallmolecule inhibitors of the tyrosine kinase domain of epidermal growth factor receptor (EGFR) may be useful in this regard (1). Gefitinib (trial code, ZD1839) is an orally administered EGFR inhibitor with a safety profile comparable
Reprint requests to: Akseli Hemminki, Biomedicum, PO Box 63, 00014 University of Helsinki, Finland. Tel: (+358) 9 191 25 464; Fax: (+358) 9 1912 5465; E-mail: [email protected] Greetta Joensuu and Timo Joensuu contributed equally to this work. This study was supported by AstraZeneca, HUCH Research Funds (EVO), Finnish Cancer Society, Sigrid Juselius Foundation, Academy of Finland, Biocentrum Helsinki and University of
Helsinki. Conflict of interest: none. Acknowledgment—We thank Arja Vilkko, Chief Research Coordinator of International Comprehensive Cancer Center Docrates. Akseli Hemminki is K. Albin Johansson Research Professor of the Foundation for the Finnish Cancer Institute. Received March 31, 2009, and in revised form July 20, 2009. Accepted for publication July 22, 2009.
INTRODUCTION
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Gefitinib with RT for prostate cancer d G. JOENSUU et al.
to chemotherapy, which has allowed it to be used in more than 300,000 cancer patients (2–4). Despite the well-established radiosensitizing activity of EGFR inhibition (5–7), the combination of gefitinib and radiation therapy has been investigated in only a few small trials with glioma, head and neck cancer, lung cancer, and pancreatic cancer patients, and therefore, the safety and utility of this approach is largely unknown (8–14). Gefitinib has not been studied previously in the context of prostate cancer radiotherapy. EGFR expression is a hallmark of many types of solid tumors including prostate cancer (15–18). Studies have reported high EGFR expression in 18 to 41% of nonmetastatic prostate cancers (19, 20). Furthermore, EGFR expression levels may be prognostic in prostate cancer. Moreover, activation of EGFR and downstream signaling pathways are implicated in cell survival and proliferation following radiation (21–23). High levels of EGFR expression appear to reduce radiation-induced apoptosis and to correlate inversely with radiocurability (24, 25). Exposure of tumor cells to radiation results in immediate activation of EGFR by autophosphorylation (26) and a secondary prolonged release of TGF-alpha (23). This creates an autocrine loop, which is important for proliferation and is thought to play a part in accelerated repopulation following radiation (27). EGFR activation of downstream pathways including the Ras/Raf/ MAPK and STAT3 pathways results in protection from radiation-induced cell death (28, 29). Furthermore, EGFR activation appears to reduce the activity of DNA damage repair, e.g., by DNA-dependent protein kinase or Ku70/80 (30). Therefore, inhibition of EGFR is an attractive approach for increasing the therapeutic efficacy of radiation by both radiosensitization and antiproliferative mechanisms. The purpose of this study was to investigate the feasibility of combining gefitinib with three-dimensional external beam radiation therapy for first-line treatment of stage T2 to T3 prostate cancer. METHODS AND MATERIALS Trial design This was a single-center, nonrandomized, open-label, two-part investigator-initiated trial. Part A of the trial had a safety design to estimate the tolerability of a 250-mg gefitinib dose given in combination with three-dimensional radiation therapy for patients with nonmetastatic prostate cancer. In Part B of the trial, the feasibility of a 250-mg gefitinib dose given in combination with radiation was estimated in a larger group of patients with nonmetastatic prostate cancer. The trial protocol and informed consent forms were approved by the Helsinki University Central Hospital Surgical Ethics Committee. The trial was performed according to good clinical practices and the Declaration of Helsinki (trial identifier, NCT00239291; AZ study code, ZD1839/IL0118).
Inclusion and exclusion criteria The inclusion criteria consisted of written informed consent; histologically confirmed localized (T2) or locally advanced (T3) prostate cancer; age 18 or older; a prostate-specific antigen (PSA) concentration of less than 20 ng/mL; lymph node negative (N0; defined as no pelvic lymph nodes larger than 1.5 cm as seen on com-
43
puted tomography [CT] scan); no metastases, as determined by a radioisotope bone scan and CT; and World Health Organization performance score of 0 to 1. Exclusion criteria were well-differentiated stage T2 prostate cancer (Gleason score of 2–4); known or suspected metastases, hypersensitivity to gefitinib, chronic toxicity greater than grade 2, prostatectomy, severe skin disorders, significant ocular abnormality, other malignancies diagnosed within the previous 5 years, absolute neutrophil count of less than 1.5109/ L, platelet count of less than 120109/L, serum bilirubin greater than the upper limit of normal (ULN), aspartate aminotransferase (AST) level of >1.25ULN, alanine aminotransferase (ALT) level of >1.25ULN, alkaline phosphatase (ALP) level of >1.25ULN, evidence of severe or uncontrolled systemic disease, serum creatinine level greater than 1.5ULN; concomitant use of phenytoin, carbamazepine, barbiturates, rifampicin or St. John’s wort; and evidence of clinically active interstitial lung disease. Adjuvant or neoadjuvant luteinizing hormone-releasing hormone analogues, antiandrogens, or other hormone treatments were not allowed. The trial treatment was discontinued if the patient withdrew consent, was lost to follow-up, protocol noncompliance occurred, or the patient died.
Dose-limiting toxicity Toxicity was scored according to the National Cancer Institute Common Toxicity Criteria version 2.0. Dose-limiting toxicity (DLT) was defined as drug-related grade 4 hematological toxicity, trial drug-related grade 3 nonhematological toxicity, any serious adverse event, treatment interruption for longer than 14 days due to trial drug-related toxicity, more than three interruptions in treatment (excluding equipment malfunction), or death from any cause. If three or more patients experienced DLT, the maximum tolerated dose was exceeded.
Treatment schedule Gefitinib was administered from day 1 continuously throughout the trial period until the end of radiotherapy (a treatment duration of 60 days) (Fig. 1). Radiation was administered from day 8 for approximately 53 days. Radiation at 50.4 Gy (1.8 Gy per day) was given to the seminal vesicles, prostate gland, and tumor extensions outside the prostate, with a 1-cm margin, in 28 fractions (5 days per week). Thereafter, 22 Gy (2 Gy per day) was given to the prostate and to tumor extensions, with a 1-cm margin, except for 0.6 cm toward the rectum, in 11 fractions (11 days). The total dose therefore consisted of 72.4 Gy given in 39 fractions, and the total treatment time was approximately 53 days. A linear accelerator with photon energy from 6 to 18 MeV was used to deliver irradiation. Doses were prescribed according to International Commission on Radiation Units and Measurements specification 50, where the reference point was chosen centrally within the planned target volume.
Endpoints The primary endpoint of the study was the incidence of DLTs. In part B of the trial, endpoints included the nature, incidence, and severity of adverse events, the incidence of and reasons for trial drug dose interruptions and reductions, trial drug exposure, laboratory assessments, and physical examination. Secondary endpoints included analysis of EGFR expression and activation status, and patients were also followed to obtain preliminary information about treatment efficacy. PSA relapse was defined using the ASTRO equation, nadir value + 2 ng/mL (31). Follow-up data were compared to those for matched controls (n = 91 patients) treated with radiation only, from a series of patients from the Cleveland Clinic (32). To ensure
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Fig. 1. Diagram showing the number of patients proceeding through the study. All 42 patients in whom toxicity was analyzed received radiation therapy. AE = adverse event. fair comparison, control patients were treated with slightly higher total doses (74–78 Gy in 2-Gy fractions, which is also a higher biologically effective dose).
EGFR analysis Analysis was performed with monoclonal NCL-EGFR antibody (Novocastra Laboratories, Newcastle, UK), which detects wildtype EGFR. The expression level was defined as the intensity of staining equal to or higher than that of normal prostate epithelial tissue. Another staining was done with NCL EGF-RT (Novocastra Laboratories), which detects EGFR varIII (33). EGFR varIII glioblastomas were used as a positive control. Amplification of EGFR expression was analyzed with chromogenic in situ hybridization (chromogenic in situ hybridization [CISH]; Zymed Inc., South San Francisco, CA). Criteria for amplification were the same as for HER-2/neu, in a similar assay (34). EGFR activation analysis was analyzed immunohistochemically using a monoclonal antibody against p-EGFR1 (Santa Cruz Biotechnology, Inc., CA). The antibody detects the tyrosine-phosphorylated (Tyr1173) form of EGFR on paraffin sections.
Cytokine analysis Cytokine analysis of serum samples was performed with BD cytometric bead array human soluble protein Flex set (Becton Dickinson, Franklin Lakes, NJ) according to the manufacturer’s instructions.
Statistics The survival rates of patients in the treatment group (72.4 Gy/1.8 Gy plus gefitinib) and in the radiation only group (74–78 Gy/2 Gy radiation only) were evaluated using the Kaplan-Meier survival plot with log rank regression (SPSS version 15.0 software for Windows).
RESULTS Safety Patient characteristics are shown in Table 1. Median time on trial was 154.0 days (range, 19 to 197 days), and median exposure to gefitinib (time on treatment) was 55.0 days (range, 19 to 71 days). Thirty (71.4%) patients had one or more dose interruptions due to toxicity. Thirty-nine (92.9%) patients had one or more interruptions of radiotherapy due to toxicity in 4 (9.5%) cases. Thirty (71.4%) patients completed the trial, and 12 (28.6%) patients discontinued because of adverse events (Table 2). All 42 (100.0%) patients in the trial experienced adverse events (Table 3). The most common events were gastrointestinal disorders in 40 (95.2%) patients, renal and urinary disorders in 36 (85.7%) patients, and skin and subcutaneous tissue disorders in 34 (81.0%) patients. Proctitis, pollakisuria, diarrhea, and dysuria, which are typical side effects of radiation therapy, were the adverse events most commonly reported individually, affecting 31 (73.8%), 30 (71.4%), 27 (64.3%), and 24 (57.1%) patients, respectively. Serious adverse events and dose-limiting toxicity Serious adverse events (SAE) were seen in 3 (7.1%) patients. In 1 patient, three events possibly related to gefitinib (cardiomegaly, cardiac failure, and myocarditis) were considered to have led to death. Other SAEs consisted of pyrexia, gastroenteritis, and renal insufficiency (in the same patient); bladder pain and pollakisuria in 1 patient; and ureteric stone in a third patient. Although the SAE in the last two patients might have been related to gefitinib, the
Gefitinib with RT for prostate cancer d G. JOENSUU et al.
Table 1. Patient population treated with gefitinib Demographic characteristics Sex Male Age (years) Mean SD Range Race White Baseline characteristics T2 T3 N0 Gleason 4–5 Gleason 6 Gleason 7 Gleason 8 PSA before treatment Mean SD Range WHO performance status 0 1 Radiation dose 72.4 Gy Discontinuation of treatment Did not prematurely discontinue trial medication Prematurely discontinued trial medication Prematurely discontinued trial medication because of adverse events
No. of patients with toxicity grade as shown*
42 (100.0)
Toxicity
1
2
65.9 6.37 47-75
Proctitis Diarrhea Meteorism Pollakisuria Dysuria Nocturia Elevated ALT Elevated AST Acne Dryness of skin Dermatitis Tiredness Hematuria Heartburn Nausea Hematemesis Eczema Pruritus cutis Dryness of eyes Decrease of appetite Skin tenderness Insomnia Dryness of mouth Dry lips Taste disturbance Epistaxis Rhinitis Urticaria Fever Acute gastroenteritis with fever Renal insufficiency Subdural hematoma Hypertrophy/ cardiomyopathy and heart insufficiency Ureteric stone
19 26 11 21 20 10 9 16 14 13 10 12 5 4 4 2 2 3 3 3 2 2 2 2 2 2 2 1 2
12 1
42 (100.0) 37 (88.1) 5 (11.9) 42 (100.0) 6 (14.3) 17 (40.5) 17 (40.5) 2 (4.8) 8.4 3.9 1.6-18.8 29 (69.0) 13 (31.0) 42 (100.0) 30 (71.4) 12 (28.6) 12 (28.6)
symptoms of the second patient are typical of radiation therapy, while the ureteric stone in the third patient may have been due to chance. Nine other patients (28.6%) discontinued trial treatment because of adverse events, which consisted of 9 cases of grade 1 to 4 ALT increase and 7 Table 2. Summary of adverse events in intent-to-treat scenario
Any adverse event Serious adverse events Adverse events leading to death CTC grade 3 or 4 adverse event Withdrawal due to adverse events Withdrawal due to serious adverse events
Table 3. Overall toxicity
No. of patients (% of total)
Abbreviations: SD = standard deviation.
Category
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No. of patients who No. of patients who had an adverse event had an adverse event in the category in each category possibly related to (% of total)* gefitinib (% of total) 42 (100.0) 3 (7.1)
42 (100) 3 (7.1)
1 (2.4)
1 (2.4)
14 (33.3)
14 (33.3)
12 (28.6)
12 (28.6)
3 (7.1)
3 (7.1)
Abbreviations: CTC = common toxicity criteria. * Patients with multiple events in the same category are counted only once in that category. Patients with events in more than one category are counted once in each of those categories.
5 3 5 10 9 3
3
4 1 1 6 5
4
1 1
1
1
1 1
Grade Grade 1-2 3-4 73.8 64.3 26.2 61.9 54.8 35.7 45.2 59.5 40.5 31.0 26.2 28.6 11.9 9.5 9.5 4.8 7.1 7.1 7.1 7.1 4.8 4.8 4.8 4.8 4.8 4.8 4.8 2.4 4.8
9.5 2.4 2.4 16.7 14.3
2.4 2.4
1 1 1
1
% of patients
2.4 2.4 2.4
2.4
* Grade 1-2 toxicities occurring in only 1 patient are not listed.
cases of grade 2 to 4 AST increase. None of the stopping rules was activated, and thus, the maximum tolerated dose was not exceeded. Overall, we recorded dose-limiting toxicities in 16 (38.1%) patients. The most common toxicities were transaminase increases (9 [ 21.4%] patients had increased ALT or AST or both). The median time to transaminase elevation was 42 days (range, 26–64 days). One patient had urticaria as well as increased transaminase levels. One patient had subdural hematoma, and 2 patients had pollakisuria. Of the remaining 3 patients, 1 patient had bladder pain and pollakisuria, another patient had a ureteric stone, and the third patient had gastroenteritis, renal insufficiency, cardiac failure, pyrexia, myocarditis, and cardiomegaly. In general, the side effect profile of gefitinib was as expected, including dyspepsia, nausea, acne, dry skin, eczema, and pruritus.
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Table 4. EGFR expression Expression
No. of patients (% of total)
EGFR IHC 100% EGFR IHC 50–80% EGFR IHC 0% EGFR IHC NA EGFR amplification EGFRvIII pEGFR
17 (40.5) 12 (28.6) 1 (2.4) 12 (28.6) 0 (0) 0 (0) 0 (0)
Abbreviations: IHC = immunohistochemistry; NA = not available.
Transaminase increases and PSA decreases Notably, increased transaminase levels were seen in 31 (73.8%) patients, and this was attributed to gefitinib. There were 7 cases of grade 3 or 4 ALT increase and 6 cases of AST increase. Transaminase increases were a frequent cause of temporary treatment interruption. Transaminase changes were plotted against PSA reduction (not shown), and there seemed to be a trend toward more-rapid PSA decrease in patients who had higher transaminase levels, but because PSA decreased rapidly in all patients, it is not possible to draw any conclusions at this point. EGFR expression High EGFR expression (in 100% of cells) was seen in 17 (40.5%) patients, with immunohistochemistry (Table 4). Elevated EGFR expression (50–80%) was seen in 12 patients (28.6%). No EGFR expression was seen in 1 (2.4%) patient. EGFR expression data were not available for 12 (28.6%) patients. EGFR amplifications, EGFRvIII, and phosphorylated EGFR (pEGFR) were not seen in any samples. Analyses were controlled with glioma specimens positive for EGFRvIII and head and neck cancer specimens featuring pEGFR. CISH was internally controlled by the presence of normal signals in each sample. Cytokine analysis We hypothesized that cytokines such as tumor necrosis factor (TNF), interleukin-1alpha (IL-1alpha), and IL-6 might underlie the liver toxicity (35, 36). However, we found that cytokine levels in general were low and that there was no correlation between serum levels of TNF, IL-1 alpha, or IL-6 and ALT elevation (data not shown). Follow-up of patients After 5 years (median 36.4 months) of follow-up, recurrence-free cumulative survival was 100% (Fig. 2A); PSArelapse free cumulative survival was 97% (Fig. 2B); salvage therapy-free cumulative survival was 61% (Fig. 2C); and overall cumulative survival was 87% (Fig. 2D). The respective values in matched patients treated with radiation only (with a slightly higher total dose: 74–78 Gy in 2-Gy fractions) were 96% (p = 0.27) for recurrence-free cumulative survival, 79 % (p = 0.06) for PSA relapse-free cumulative survival, 89% (p = 0.93) for salvage therapyfree cumulative survival, and 87% (p = 0.57) for overall
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cumulative survival. The biologically effective dose of 74 to 78/2 Gy is higher than 72.4/1.8 Gy. DISCUSSION Radical prostatectomy and radiotherapy fail to cure a substantial proportion of T2–T3 prostate cancer patients. Therefore, combination approaches with, e.g., hormones have been evaluated for improving treatment results. However, hormone therapies cause substantial immediate and delayed side effects, and they are therefore usually used only in high-risk cases. Also, despite the increased disease-free survival associated with adjuvant and neoadjuvant hormone treatments, disease recurs in a proportion of patients. Therefore, increasing the efficacy of primary treatment (e.g., radiotherapy) would be appealing. Although none of the patients in this trial received hormone therapies, there is a trend toward its increasing use even in medium-risk patients. The combination of hormone therapies with gefitinib and radiation might impact safety and efficacy results and is an interesting subject for further studies. There are no previous clinical trials in which an EGFR inhibitor would have been combined with radiotherapy for treatment of prostate cancer. Therefore, a safety estimation of 250 mg gefitinib given in combination with radiation was performed. Gefitinib was given orally, daily and continuously, 7 days before radiation and then in combination with radiation for 7.5 weeks. The 250-mg dose was selected based on clinical and pharmacokinetic data obtained from phase I to III trials (3, 37, 38). Overall, the treatment was relatively well tolerated. However, one death occurred during the trial, and it is not possible to exclude the possibility that gefitinib and/or the combination with radiation played a causative or contributing role. The patient had a history of intermittent claudication and surgery for aortic stenosis. Cardiomegaly may have also been a preexisting condition as the patient had systolic hypertension (185 mm Hg) and abnormal electrocardiogram results. There was a case of grade 3 cystitis, which would be a typical side effect associated with radiation. However, it is possible that it was exacerbated by gefitinib. The third serious adverse event (ureteric stone) may have been unrelated to the treatments administered. Notably, however, liver enzyme elevation was seen in 73.8 % of patients, and in 14.3% and 2.4% of patients, respectively, the elevations were scored as grade 3 or 4. While EGFR inhibitors are known to sometimes increase transaminase levels, grade 3 to 4 elevations are rarely seen (3, 39–41). For example, in a recent trial, Small et al. (42) reported only 2 cases of grade 1 transaminase increase in 58 prostate cancer patients, despite the use of a gefitinib dose twice that used in the present study. No transaminase increases were reported in another prostate cancer trial where gefitinib was used at either 250 mg or 500 mg (43). Although there are only a few trials featuring gefitinib in combination with radiation, some cases of transaminitis
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Fig. 2. (A) Prostate cancer-free survival, (B) PSA relapse-free survival, (C) salvage therapy-free survival, and (D) overall survival of patients treated with external beam radiation in combination with gefitinib versus matched controls treated with radiation only.
have been reported. For example, Maurel et al. (10) reported 1 of 6 pancreatic cancer patients who had grade 3 transaminitis. Also, Caponigro and colleagues (8) reported grade 1 transaminitis in 3 and grade 3 transaminitis in another 3 head and neck cancer patients treated with 250 mg gefitinib (out of 12 patients total). In contrast, Chen et al. (9) reported only grade 1 transaminitis in head and neck cancer patients who received 250 or 500 mg of gefitinib, and some of these patients evidently also received chemotherapy. Suggesting that radiation dose or volume might play a role, a study using radiosurgery in combination with gefitinib for treatment of glioma reported only grade 1 liver enzyme elevations in 2/15 patients (44). Although transaminase elevations were asymptomatic and did not lead to sequelae in any patients, modification of radiation delivery might reduce the occurrence of this side effect. For example, utilization of brachytherapy with high-doserate delivery, with or without external fields, would reduce the duration of gefitinib therapy from the 9 weeks used in the present study to 5 or 4 weeks. Since the liver enzyme
elevations seen in this trial occurred at a median of 6 weeks, more rapid radiation delivery might be advantageous. We hypothesized that cytokines such as TNF, IL-1alpha, or IL-6, released from the prostate upon radiation might underlie or exacerbate the liver toxicity of gefitinib. These are cytokines known to be released as a result of radiation (35, 36). However, we found that interleukin levels in general were low and that there was no correlation between them and ALT elevation. EGFR expression in immunohistochemistry results were seen in a significant proportion of patients. This is well in accord with previous reports (45). No cases of activated pEGFR were seen. A previous study reported pEGFR in 17% of cases, confirming the rarity of pEGFR in untreated hormone-sensitive disease (45). Also in parallel with previous work, EGFR amplification seems to be quite rare; we did not see any cases, while Schlomm et al. (20) reported amplification in 3.3% of patients. In contrast to a previous report, EGFRvIII was not seen in our study (46). We used a different antibody, which might partially explain the findings.
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Alternatively, patient ethnicity might play a role. Purely technical issues are unlikely to explain the lack of EGFRvIII in our analyses, as they were controlled with glioma specimens confirmed to be positive for EGFRvIII. CONCLUSIONS In summary, the overall safety of gefitinib in combination with prostate cancer radiotherapy appears to be acceptable, as less than 10% of patients had toxicity-related interruptions of radiotherapy. Liver enzyme elevations were frequently observed, but they were easily managed by temporarily interrupting gefitinib therapy. The preliminary efficacy of the combination seems quite promising compared to matched
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controls treated with a slightly higher biologically effective dose, but it is clear that the usual caveats of nonrandomized comparisons apply. For example, since controls were treated earlier, advances in treatment planning and delivery may have also played a role in improving treatment results. Efficacy of the combination can be studied reliably only in a randomized study. In addition to possibly increasing the disease control rate, the combination might also be useful for reducing side effects known to be associated with high (e.g., more than 72 Gy) radiation doses, if it allows efficacy to be maintained with a lower total dose. When considering a randomized phase III study to assess the efficacy of this approach, it is key to contemplate possible gains in efficacy versus increases in toxicity.
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(74 Gy) with concurrent carboplatin, paclitaxel, and gefitinib in unresectable stage IIIA and stage IIIB non-small cell lung cancer. J Thoracic Oncol 2008;3:250–257. Ma S, Xu Y, Deng Q, et al. Treatment of brain metastasis from non-small cell lung cancer with whole brain radiotherapy and gefitinib in a Chinese population. Lung Cancer 2008;60:208–214. Hynes NE, Lane HA. ERBB receptors and cancer: the complexity of targeted inhibitors. Nat Rev Cancer 2005;5:341–354. Shuch B, Mikhail M, Satagopan J, et al. Racial disparity of epidermal growth factor receptor expression in prostate cancer. J Clin Oncol 2004;22:4725–4729. Torring N, Dagnaes-Hansen F, Sorensen BS, et al. ErbBI and prostate cancer: ErbBI activity is essential for androgen-induced proliferation and protection. Prostate 2003;56:142–149. Normanno N, DeLuca A, Bianco C, et al. Epidermal growth factor receptor (EGFR) signaling in cancer. Gene 2006;366: 2–16. DiLorenzo G, Tortora G, D’Armiento FP, et al. Expression of epidermal growth factor receptor correlates with disease relapse and progression to androgen-independence in human prostate cancer. Clin Cancer Res 2002;8:3438–3444. Schlomm T, Kirstein P, Iwers L, et al. Clinical significance of epidermal growth factor receptor protein overexpression and gene copy number gains in prostate cancer. Clin Cancer Res 2007;13:6579–6584. Chen DJ, Nirodi CS. The epidermal growth factor receptor: A role in repair of radiation-induced DNA damage. Clin Cancer Res 2007;13:6555–6560. Rodemann HP, Dittmann K, Toulany M. Radiation-induced EGFR-signaling and control of DNA-damage repair. Int J Radiat Biol 2007;83:781–791. Dent P, Reardon DB, Park JS, et al. Radiation-induced release of transforming growth factor alpha activates the epidermal growth factor receptor and mitogen-activated protein kinase pathway in carcinoma cells leading to increased proliferation and protection from radiation-induced cell death. Mol Biol Cell 1999;10:2493–2506. Akimoto T, Hunter NR, Buchmiller L, et al. Inverse relationship between epidermal growth factor receptor expression and radiocurability of murine carcinomas. Clin Cancer Res 1999;5: 2884–2890. Sheridan M, O’Dwyer T, Seymour C, et al. Potential indicators of radiosensitivity in squamous cell carcinoma of the head and neck. Radiat Oncol Investig 1997;5:180–186. Schmidt-Ullrich R, Mikkelsen R, Dent P, et al. Radiation-induced proliferation of the human A431 squamous carcinoma cells is dependent on EGFR tyrosine phosphorylation. Oncogene 1997;15:1191–1197.
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27. Schmidt-Ullrich R, Valerie K, Fogleman P, et al. Radiation-induced autophosphorylation of epidermal growth factor receptor in human malignant mammary and squamous epithelial cells. Radiat Res 1996;145:81–85. 28. Carter S, Auer KL, Reardon DB, et al. Inhibition of the mitogen activated protein (MAP) kinase cascade potentiates cell killing by low dose ionizing radiation in A431 human squamous carcinoma cells. Oncogene 1998;16:2787–2796. 29. Grandis JR, Drenning SD, Chakraborty A, et al. Requirement of Stat3 but not Stat1 activation for epidermal growth factor receptor-mediated cell growth in vitro. J Clin Investig 1998;102: 1385–1392. 30. Bandyopadhyay D, Mandal M, Adam L, et al. Physical interaction between epidermal growth factor receptor and DNA-dependent protein kinase in mammalian cells. J Biol Chem 1998;273:1568–1573. 31. Roach M III, Hanks G, Thames H Jr., et al. Defining biochemical failure following radiotherapy with or without hormonal therapy in men with clinically localized prostate cancer: Recommendations of the RTOG-ASTRO Phoenix Consensus Conference. Int J Radiat Oncol Biol Phys 2006;65:965–974. 32. Kupelian P, Kuban D, Thames H, et al. Improved biochemical relapse-free survival with increased external radiation doses in patients with localized prostate cancer: the combined experience of nine institutions in patients treated in 1994 and 1995. Int J Radiat Oncol Biol Phys 2005;61:415–419. 33. Novocastra Laboratories Ltd. NCL-EGFR. Instructions for use. 2004. 34. Isola J, Tanner M, Forsyth A, et al. Interlaboratory comparison of HER-2 oncogene amplification as detected by chromogenic and fluorescence in situ hybridization. Clin Cancer Res 2004; 10:4793–4798. 35. Kimura H, Kasahara K, Sekijima M, et al. Plasma MIP-1beta levels and skin toxicity in Japanese non-small cell lung cancer patients treated with the EGFR-targeted tyrosine kinase inhibitor gefitinib. Lung Cancer 2005;20:393–399. 36. Kovacs CJ, Daly BM, Evans MJ, et al. Cytokine profiles in patients receiving wide-field plus prostate boost radiotherapy
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(xRT) for adenocarcinoma of the prostate. Cytokine 2003;23: 151–163. Ranson M, Hammond LA, Ferry D, et al. ZD1839, a selective oral epidermal growth factor receptor-tyrosine kinase inhibitor, is well tolerated and active in patients with solid, malignant tumors: Results of a phase I trial. J Clin Oncol 2002;20:2240–2250. Fukuoka M, Yano S, Giaccone G, et al. Multi-institutional randomized phase II trial of gefitinib for previously treated patients with advanced non-small-cell lung cancer. J Clin Oncol 2003; 21:2237–2246. Costa DB, Kobayashi S, Tenen DG, et al. Pooled analysis of the prospective trials of gefitinib monotherapy for EGFR-mutant non-small cell lung cancers. Lung Cancer 2007;58:95–103. Asahina H, Yamazaki K, Kinoshita I, et al. A phase II trial of gefitinib as first-line therapy for advanced non-small cell lung cancer with epidermal growth factor receptor mutations. Brit J Cancer 2006;95:998–1004. Sutani A, Nagai Y, Udagawa K, et al. Gefitinib for non-smallcell lung cancer patients with epidermal growth factor receptor gene mutations screened by peptide nucleic acid-locked nucleic acid PCR clamp. Brit J Cancer 2006;95:1483–1489. Small EJ, Fontana J, Tannir N, et al. A phase II trial of gefitinib in patients with non-metastatic hormone-refractory prostate cancer. BJU Int 2007;100:765–769. Canil CM, Moore MJ, Winquist E, et al. Randomized phase II study of two doses of gefitinib in hormone-refractory prostate cancer: A trial of the National Cancer Institute of Canada-Clinical Trials Group. J Clin Oncol 2005;23:455–460. Schwer AL, Damek DM, Kavanagh BD, et al. A phase I doseescalation study of fractionated stereotactic radiosurgery in combination with gefitinib in patients with recurrent malignant gliomas. Int J Radiat Oncol Biol Phys 2008;70:993–1001. Gravina GL, Festuccia C, Galatioto GP, et al. Surgical and biologic outcomes after neoadjuvant bicalutamide treatment in prostate cancer. Urology 2007;70:728–733. Olapade-Olaopa E, Moscatello D, MacKay E, et al. Evidence for the differential expression of a variant EGF receptor protein in human prostate cancer. Brit J Cancer 2000;82:186–194.
doi:10.1016/j.ijrobp.2009.07.1731
CLINICAL INVESTIGATION
Prostate
A PHASE I/II TRIAL OF GEFITINIB GIVEN CONCURRENTLY WITH RADIOTHERAPY IN PATIENTS WITH NONMETASTATIC PROSTATE CANCER GREETTA JOENSUU, B.M.,*y TIMO JOENSUU, M.D., PH.D.,y PETRI NOKISALMI, M.SC., B.M.,*z CHANDANA REDDY, M.SC.,{ JORMA ISOLA, M.D., PH.D.,** MIRJA RUUTU, M.D., PH.D.,x MAURI KOURI, M.D., PH.D.,y PATRICK A. KUPELIAN, M.D.,yy JUHANI COLLAN, M.D.,zz SARI PESONEN, PH.D.,*z AND AKSELI HEMMINKI, M.D., PH.D.*z *Cancer Gene Therapy Group, Molecular Cancer Biology Program and Transplantation Laboratory and Haartman Institute and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland; yInternational Comprehensive Cancer Center Docrates, Helsinki, Finland; zHUSLAB, xDepartment of Urology, Helsinki University Central Hospital, Helsinki, Finland; {Radiation Oncology, Cleveland Clinic, Cleveland, Ohio; **Institute of Medical Technology, University of Tampere, Tampere, Finland; yyDepartment of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, Florida; and zzDepartment of Oncology, Helsinki University Central Hospital, Helsinki, Finland Purpose: To estimate the safety and tolerability of daily administration of 250 mg of gefitinib given concurrently with three-dimensional conformal radiotherapy for patients with nonmetastatic prostate cancer. Methods and Materials: A total of 42 patients with T2–T3N0M0 tumors were treated in a nonrandomized singlecenter study. A prostate-specific antigen (PSA) level of <20 and a good performance status (WHO, 0–1) were required. Adjuvant or neoadjuvant hormone treatments were not allowed. A daily regimen of 250 mg of gefitinib was started 1 week before radiation therapy began and lasted for the duration of radiation therapy. A dose of 50.4 Gy (1.8 Gy/day) was administered to the tumor, prostate, and seminal vesicles, followed by a 22-Gy booster (2 Gy/day) for a total dose of 72.4 Gy. Correlative studies included analysis of epidermal growth factor receptor (EGFR), EGFRvIII, and phosphorylated EGFR in tumors and tumor necrosis factor, interleukin-1a (IL-1a), and IL-6 in serum. Results: Maximum tolerated dose was not reached in phase I (12 patients), and 30 additional patients were treated in phase II. Thirty (71.4%) patients completed trial medication. Dose-limiting toxicities were recorded for 16 (38.1%) patients, the most common of which was a grade 3 to 4 increase in transaminase (6 patients). After a median follow-up of 38 months, there were no deaths due to prostate cancer. The estimated PSA relapse-free survival rate at 4 years (Kaplan-Meier) was 97%, the salvage therapy-free survival rate was 91%, and the overall survival rate was 87%. These figures compared favorably with those of matched patients treated with radiation only at higher doses. Conclusions: The combination of gefitinib and radiation is reasonably well tolerated and has promising activity against nonmetastatic prostate cancer. Ó 2010 Elsevier Inc. Gefitinib, Radiotherapy, Nonmetastatic prostate cancer, EGFR targeted therapy, Chemotherapy.
Prostate cancer is the most commonly diagnosed malignancy and the second leading cause of male cancer death in the Western world. The median 5-year disease-free survival rate for local stage T2 or locally advanced stage T3 prostate cancer patients varies from 30% to 90% in different series. Despite increased awareness and earlier diagnosis, therapy with curative intent seems to fail to achieve long-term cure
in a substantial proportion of patients. Therefore, it is important to identify approaches that can increase cure rates. One promising approach is a combination of radiotherapy and a targeted drug. Preclinical evidence suggests that smallmolecule inhibitors of the tyrosine kinase domain of epidermal growth factor receptor (EGFR) may be useful in this regard (1). Gefitinib (trial code, ZD1839) is an orally administered EGFR inhibitor with a safety profile comparable
Reprint requests to: Akseli Hemminki, Biomedicum, PO Box 63, 00014 University of Helsinki, Finland. Tel: (+358) 9 191 25 464; Fax: (+358) 9 1912 5465; E-mail: [email protected] Greetta Joensuu and Timo Joensuu contributed equally to this work. This study was supported by AstraZeneca, HUCH Research Funds (EVO), Finnish Cancer Society, Sigrid Juselius Foundation, Academy of Finland, Biocentrum Helsinki and University of
Helsinki. Conflict of interest: none. Acknowledgment—We thank Arja Vilkko, Chief Research Coordinator of International Comprehensive Cancer Center Docrates. Akseli Hemminki is K. Albin Johansson Research Professor of the Foundation for the Finnish Cancer Institute. Received March 31, 2009, and in revised form July 20, 2009. Accepted for publication July 22, 2009.
INTRODUCTION
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Gefitinib with RT for prostate cancer d G. JOENSUU et al.
to chemotherapy, which has allowed it to be used in more than 300,000 cancer patients (2–4). Despite the well-established radiosensitizing activity of EGFR inhibition (5–7), the combination of gefitinib and radiation therapy has been investigated in only a few small trials with glioma, head and neck cancer, lung cancer, and pancreatic cancer patients, and therefore, the safety and utility of this approach is largely unknown (8–14). Gefitinib has not been studied previously in the context of prostate cancer radiotherapy. EGFR expression is a hallmark of many types of solid tumors including prostate cancer (15–18). Studies have reported high EGFR expression in 18 to 41% of nonmetastatic prostate cancers (19, 20). Furthermore, EGFR expression levels may be prognostic in prostate cancer. Moreover, activation of EGFR and downstream signaling pathways are implicated in cell survival and proliferation following radiation (21–23). High levels of EGFR expression appear to reduce radiation-induced apoptosis and to correlate inversely with radiocurability (24, 25). Exposure of tumor cells to radiation results in immediate activation of EGFR by autophosphorylation (26) and a secondary prolonged release of TGF-alpha (23). This creates an autocrine loop, which is important for proliferation and is thought to play a part in accelerated repopulation following radiation (27). EGFR activation of downstream pathways including the Ras/Raf/ MAPK and STAT3 pathways results in protection from radiation-induced cell death (28, 29). Furthermore, EGFR activation appears to reduce the activity of DNA damage repair, e.g., by DNA-dependent protein kinase or Ku70/80 (30). Therefore, inhibition of EGFR is an attractive approach for increasing the therapeutic efficacy of radiation by both radiosensitization and antiproliferative mechanisms. The purpose of this study was to investigate the feasibility of combining gefitinib with three-dimensional external beam radiation therapy for first-line treatment of stage T2 to T3 prostate cancer. METHODS AND MATERIALS Trial design This was a single-center, nonrandomized, open-label, two-part investigator-initiated trial. Part A of the trial had a safety design to estimate the tolerability of a 250-mg gefitinib dose given in combination with three-dimensional radiation therapy for patients with nonmetastatic prostate cancer. In Part B of the trial, the feasibility of a 250-mg gefitinib dose given in combination with radiation was estimated in a larger group of patients with nonmetastatic prostate cancer. The trial protocol and informed consent forms were approved by the Helsinki University Central Hospital Surgical Ethics Committee. The trial was performed according to good clinical practices and the Declaration of Helsinki (trial identifier, NCT00239291; AZ study code, ZD1839/IL0118).
Inclusion and exclusion criteria The inclusion criteria consisted of written informed consent; histologically confirmed localized (T2) or locally advanced (T3) prostate cancer; age 18 or older; a prostate-specific antigen (PSA) concentration of less than 20 ng/mL; lymph node negative (N0; defined as no pelvic lymph nodes larger than 1.5 cm as seen on com-
43
puted tomography [CT] scan); no metastases, as determined by a radioisotope bone scan and CT; and World Health Organization performance score of 0 to 1. Exclusion criteria were well-differentiated stage T2 prostate cancer (Gleason score of 2–4); known or suspected metastases, hypersensitivity to gefitinib, chronic toxicity greater than grade 2, prostatectomy, severe skin disorders, significant ocular abnormality, other malignancies diagnosed within the previous 5 years, absolute neutrophil count of less than 1.5109/ L, platelet count of less than 120109/L, serum bilirubin greater than the upper limit of normal (ULN), aspartate aminotransferase (AST) level of >1.25ULN, alanine aminotransferase (ALT) level of >1.25ULN, alkaline phosphatase (ALP) level of >1.25ULN, evidence of severe or uncontrolled systemic disease, serum creatinine level greater than 1.5ULN; concomitant use of phenytoin, carbamazepine, barbiturates, rifampicin or St. John’s wort; and evidence of clinically active interstitial lung disease. Adjuvant or neoadjuvant luteinizing hormone-releasing hormone analogues, antiandrogens, or other hormone treatments were not allowed. The trial treatment was discontinued if the patient withdrew consent, was lost to follow-up, protocol noncompliance occurred, or the patient died.
Dose-limiting toxicity Toxicity was scored according to the National Cancer Institute Common Toxicity Criteria version 2.0. Dose-limiting toxicity (DLT) was defined as drug-related grade 4 hematological toxicity, trial drug-related grade 3 nonhematological toxicity, any serious adverse event, treatment interruption for longer than 14 days due to trial drug-related toxicity, more than three interruptions in treatment (excluding equipment malfunction), or death from any cause. If three or more patients experienced DLT, the maximum tolerated dose was exceeded.
Treatment schedule Gefitinib was administered from day 1 continuously throughout the trial period until the end of radiotherapy (a treatment duration of 60 days) (Fig. 1). Radiation was administered from day 8 for approximately 53 days. Radiation at 50.4 Gy (1.8 Gy per day) was given to the seminal vesicles, prostate gland, and tumor extensions outside the prostate, with a 1-cm margin, in 28 fractions (5 days per week). Thereafter, 22 Gy (2 Gy per day) was given to the prostate and to tumor extensions, with a 1-cm margin, except for 0.6 cm toward the rectum, in 11 fractions (11 days). The total dose therefore consisted of 72.4 Gy given in 39 fractions, and the total treatment time was approximately 53 days. A linear accelerator with photon energy from 6 to 18 MeV was used to deliver irradiation. Doses were prescribed according to International Commission on Radiation Units and Measurements specification 50, where the reference point was chosen centrally within the planned target volume.
Endpoints The primary endpoint of the study was the incidence of DLTs. In part B of the trial, endpoints included the nature, incidence, and severity of adverse events, the incidence of and reasons for trial drug dose interruptions and reductions, trial drug exposure, laboratory assessments, and physical examination. Secondary endpoints included analysis of EGFR expression and activation status, and patients were also followed to obtain preliminary information about treatment efficacy. PSA relapse was defined using the ASTRO equation, nadir value + 2 ng/mL (31). Follow-up data were compared to those for matched controls (n = 91 patients) treated with radiation only, from a series of patients from the Cleveland Clinic (32). To ensure
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Fig. 1. Diagram showing the number of patients proceeding through the study. All 42 patients in whom toxicity was analyzed received radiation therapy. AE = adverse event. fair comparison, control patients were treated with slightly higher total doses (74–78 Gy in 2-Gy fractions, which is also a higher biologically effective dose).
EGFR analysis Analysis was performed with monoclonal NCL-EGFR antibody (Novocastra Laboratories, Newcastle, UK), which detects wildtype EGFR. The expression level was defined as the intensity of staining equal to or higher than that of normal prostate epithelial tissue. Another staining was done with NCL EGF-RT (Novocastra Laboratories), which detects EGFR varIII (33). EGFR varIII glioblastomas were used as a positive control. Amplification of EGFR expression was analyzed with chromogenic in situ hybridization (chromogenic in situ hybridization [CISH]; Zymed Inc., South San Francisco, CA). Criteria for amplification were the same as for HER-2/neu, in a similar assay (34). EGFR activation analysis was analyzed immunohistochemically using a monoclonal antibody against p-EGFR1 (Santa Cruz Biotechnology, Inc., CA). The antibody detects the tyrosine-phosphorylated (Tyr1173) form of EGFR on paraffin sections.
Cytokine analysis Cytokine analysis of serum samples was performed with BD cytometric bead array human soluble protein Flex set (Becton Dickinson, Franklin Lakes, NJ) according to the manufacturer’s instructions.
Statistics The survival rates of patients in the treatment group (72.4 Gy/1.8 Gy plus gefitinib) and in the radiation only group (74–78 Gy/2 Gy radiation only) were evaluated using the Kaplan-Meier survival plot with log rank regression (SPSS version 15.0 software for Windows).
RESULTS Safety Patient characteristics are shown in Table 1. Median time on trial was 154.0 days (range, 19 to 197 days), and median exposure to gefitinib (time on treatment) was 55.0 days (range, 19 to 71 days). Thirty (71.4%) patients had one or more dose interruptions due to toxicity. Thirty-nine (92.9%) patients had one or more interruptions of radiotherapy due to toxicity in 4 (9.5%) cases. Thirty (71.4%) patients completed the trial, and 12 (28.6%) patients discontinued because of adverse events (Table 2). All 42 (100.0%) patients in the trial experienced adverse events (Table 3). The most common events were gastrointestinal disorders in 40 (95.2%) patients, renal and urinary disorders in 36 (85.7%) patients, and skin and subcutaneous tissue disorders in 34 (81.0%) patients. Proctitis, pollakisuria, diarrhea, and dysuria, which are typical side effects of radiation therapy, were the adverse events most commonly reported individually, affecting 31 (73.8%), 30 (71.4%), 27 (64.3%), and 24 (57.1%) patients, respectively. Serious adverse events and dose-limiting toxicity Serious adverse events (SAE) were seen in 3 (7.1%) patients. In 1 patient, three events possibly related to gefitinib (cardiomegaly, cardiac failure, and myocarditis) were considered to have led to death. Other SAEs consisted of pyrexia, gastroenteritis, and renal insufficiency (in the same patient); bladder pain and pollakisuria in 1 patient; and ureteric stone in a third patient. Although the SAE in the last two patients might have been related to gefitinib, the
Gefitinib with RT for prostate cancer d G. JOENSUU et al.
Table 1. Patient population treated with gefitinib Demographic characteristics Sex Male Age (years) Mean SD Range Race White Baseline characteristics T2 T3 N0 Gleason 4–5 Gleason 6 Gleason 7 Gleason 8 PSA before treatment Mean SD Range WHO performance status 0 1 Radiation dose 72.4 Gy Discontinuation of treatment Did not prematurely discontinue trial medication Prematurely discontinued trial medication Prematurely discontinued trial medication because of adverse events
No. of patients with toxicity grade as shown*
42 (100.0)
Toxicity
1
2
65.9 6.37 47-75
Proctitis Diarrhea Meteorism Pollakisuria Dysuria Nocturia Elevated ALT Elevated AST Acne Dryness of skin Dermatitis Tiredness Hematuria Heartburn Nausea Hematemesis Eczema Pruritus cutis Dryness of eyes Decrease of appetite Skin tenderness Insomnia Dryness of mouth Dry lips Taste disturbance Epistaxis Rhinitis Urticaria Fever Acute gastroenteritis with fever Renal insufficiency Subdural hematoma Hypertrophy/ cardiomyopathy and heart insufficiency Ureteric stone
19 26 11 21 20 10 9 16 14 13 10 12 5 4 4 2 2 3 3 3 2 2 2 2 2 2 2 1 2
12 1
42 (100.0) 37 (88.1) 5 (11.9) 42 (100.0) 6 (14.3) 17 (40.5) 17 (40.5) 2 (4.8) 8.4 3.9 1.6-18.8 29 (69.0) 13 (31.0) 42 (100.0) 30 (71.4) 12 (28.6) 12 (28.6)
symptoms of the second patient are typical of radiation therapy, while the ureteric stone in the third patient may have been due to chance. Nine other patients (28.6%) discontinued trial treatment because of adverse events, which consisted of 9 cases of grade 1 to 4 ALT increase and 7 Table 2. Summary of adverse events in intent-to-treat scenario
Any adverse event Serious adverse events Adverse events leading to death CTC grade 3 or 4 adverse event Withdrawal due to adverse events Withdrawal due to serious adverse events
Table 3. Overall toxicity
No. of patients (% of total)
Abbreviations: SD = standard deviation.
Category
45
No. of patients who No. of patients who had an adverse event had an adverse event in the category in each category possibly related to (% of total)* gefitinib (% of total) 42 (100.0) 3 (7.1)
42 (100) 3 (7.1)
1 (2.4)
1 (2.4)
14 (33.3)
14 (33.3)
12 (28.6)
12 (28.6)
3 (7.1)
3 (7.1)
Abbreviations: CTC = common toxicity criteria. * Patients with multiple events in the same category are counted only once in that category. Patients with events in more than one category are counted once in each of those categories.
5 3 5 10 9 3
3
4 1 1 6 5
4
1 1
1
1
1 1
Grade Grade 1-2 3-4 73.8 64.3 26.2 61.9 54.8 35.7 45.2 59.5 40.5 31.0 26.2 28.6 11.9 9.5 9.5 4.8 7.1 7.1 7.1 7.1 4.8 4.8 4.8 4.8 4.8 4.8 4.8 2.4 4.8
9.5 2.4 2.4 16.7 14.3
2.4 2.4
1 1 1
1
% of patients
2.4 2.4 2.4
2.4
* Grade 1-2 toxicities occurring in only 1 patient are not listed.
cases of grade 2 to 4 AST increase. None of the stopping rules was activated, and thus, the maximum tolerated dose was not exceeded. Overall, we recorded dose-limiting toxicities in 16 (38.1%) patients. The most common toxicities were transaminase increases (9 [ 21.4%] patients had increased ALT or AST or both). The median time to transaminase elevation was 42 days (range, 26–64 days). One patient had urticaria as well as increased transaminase levels. One patient had subdural hematoma, and 2 patients had pollakisuria. Of the remaining 3 patients, 1 patient had bladder pain and pollakisuria, another patient had a ureteric stone, and the third patient had gastroenteritis, renal insufficiency, cardiac failure, pyrexia, myocarditis, and cardiomegaly. In general, the side effect profile of gefitinib was as expected, including dyspepsia, nausea, acne, dry skin, eczema, and pruritus.
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Table 4. EGFR expression Expression
No. of patients (% of total)
EGFR IHC 100% EGFR IHC 50–80% EGFR IHC 0% EGFR IHC NA EGFR amplification EGFRvIII pEGFR
17 (40.5) 12 (28.6) 1 (2.4) 12 (28.6) 0 (0) 0 (0) 0 (0)
Abbreviations: IHC = immunohistochemistry; NA = not available.
Transaminase increases and PSA decreases Notably, increased transaminase levels were seen in 31 (73.8%) patients, and this was attributed to gefitinib. There were 7 cases of grade 3 or 4 ALT increase and 6 cases of AST increase. Transaminase increases were a frequent cause of temporary treatment interruption. Transaminase changes were plotted against PSA reduction (not shown), and there seemed to be a trend toward more-rapid PSA decrease in patients who had higher transaminase levels, but because PSA decreased rapidly in all patients, it is not possible to draw any conclusions at this point. EGFR expression High EGFR expression (in 100% of cells) was seen in 17 (40.5%) patients, with immunohistochemistry (Table 4). Elevated EGFR expression (50–80%) was seen in 12 patients (28.6%). No EGFR expression was seen in 1 (2.4%) patient. EGFR expression data were not available for 12 (28.6%) patients. EGFR amplifications, EGFRvIII, and phosphorylated EGFR (pEGFR) were not seen in any samples. Analyses were controlled with glioma specimens positive for EGFRvIII and head and neck cancer specimens featuring pEGFR. CISH was internally controlled by the presence of normal signals in each sample. Cytokine analysis We hypothesized that cytokines such as tumor necrosis factor (TNF), interleukin-1alpha (IL-1alpha), and IL-6 might underlie the liver toxicity (35, 36). However, we found that cytokine levels in general were low and that there was no correlation between serum levels of TNF, IL-1 alpha, or IL-6 and ALT elevation (data not shown). Follow-up of patients After 5 years (median 36.4 months) of follow-up, recurrence-free cumulative survival was 100% (Fig. 2A); PSArelapse free cumulative survival was 97% (Fig. 2B); salvage therapy-free cumulative survival was 61% (Fig. 2C); and overall cumulative survival was 87% (Fig. 2D). The respective values in matched patients treated with radiation only (with a slightly higher total dose: 74–78 Gy in 2-Gy fractions) were 96% (p = 0.27) for recurrence-free cumulative survival, 79 % (p = 0.06) for PSA relapse-free cumulative survival, 89% (p = 0.93) for salvage therapyfree cumulative survival, and 87% (p = 0.57) for overall
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cumulative survival. The biologically effective dose of 74 to 78/2 Gy is higher than 72.4/1.8 Gy. DISCUSSION Radical prostatectomy and radiotherapy fail to cure a substantial proportion of T2–T3 prostate cancer patients. Therefore, combination approaches with, e.g., hormones have been evaluated for improving treatment results. However, hormone therapies cause substantial immediate and delayed side effects, and they are therefore usually used only in high-risk cases. Also, despite the increased disease-free survival associated with adjuvant and neoadjuvant hormone treatments, disease recurs in a proportion of patients. Therefore, increasing the efficacy of primary treatment (e.g., radiotherapy) would be appealing. Although none of the patients in this trial received hormone therapies, there is a trend toward its increasing use even in medium-risk patients. The combination of hormone therapies with gefitinib and radiation might impact safety and efficacy results and is an interesting subject for further studies. There are no previous clinical trials in which an EGFR inhibitor would have been combined with radiotherapy for treatment of prostate cancer. Therefore, a safety estimation of 250 mg gefitinib given in combination with radiation was performed. Gefitinib was given orally, daily and continuously, 7 days before radiation and then in combination with radiation for 7.5 weeks. The 250-mg dose was selected based on clinical and pharmacokinetic data obtained from phase I to III trials (3, 37, 38). Overall, the treatment was relatively well tolerated. However, one death occurred during the trial, and it is not possible to exclude the possibility that gefitinib and/or the combination with radiation played a causative or contributing role. The patient had a history of intermittent claudication and surgery for aortic stenosis. Cardiomegaly may have also been a preexisting condition as the patient had systolic hypertension (185 mm Hg) and abnormal electrocardiogram results. There was a case of grade 3 cystitis, which would be a typical side effect associated with radiation. However, it is possible that it was exacerbated by gefitinib. The third serious adverse event (ureteric stone) may have been unrelated to the treatments administered. Notably, however, liver enzyme elevation was seen in 73.8 % of patients, and in 14.3% and 2.4% of patients, respectively, the elevations were scored as grade 3 or 4. While EGFR inhibitors are known to sometimes increase transaminase levels, grade 3 to 4 elevations are rarely seen (3, 39–41). For example, in a recent trial, Small et al. (42) reported only 2 cases of grade 1 transaminase increase in 58 prostate cancer patients, despite the use of a gefitinib dose twice that used in the present study. No transaminase increases were reported in another prostate cancer trial where gefitinib was used at either 250 mg or 500 mg (43). Although there are only a few trials featuring gefitinib in combination with radiation, some cases of transaminitis
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Fig. 2. (A) Prostate cancer-free survival, (B) PSA relapse-free survival, (C) salvage therapy-free survival, and (D) overall survival of patients treated with external beam radiation in combination with gefitinib versus matched controls treated with radiation only.
have been reported. For example, Maurel et al. (10) reported 1 of 6 pancreatic cancer patients who had grade 3 transaminitis. Also, Caponigro and colleagues (8) reported grade 1 transaminitis in 3 and grade 3 transaminitis in another 3 head and neck cancer patients treated with 250 mg gefitinib (out of 12 patients total). In contrast, Chen et al. (9) reported only grade 1 transaminitis in head and neck cancer patients who received 250 or 500 mg of gefitinib, and some of these patients evidently also received chemotherapy. Suggesting that radiation dose or volume might play a role, a study using radiosurgery in combination with gefitinib for treatment of glioma reported only grade 1 liver enzyme elevations in 2/15 patients (44). Although transaminase elevations were asymptomatic and did not lead to sequelae in any patients, modification of radiation delivery might reduce the occurrence of this side effect. For example, utilization of brachytherapy with high-doserate delivery, with or without external fields, would reduce the duration of gefitinib therapy from the 9 weeks used in the present study to 5 or 4 weeks. Since the liver enzyme
elevations seen in this trial occurred at a median of 6 weeks, more rapid radiation delivery might be advantageous. We hypothesized that cytokines such as TNF, IL-1alpha, or IL-6, released from the prostate upon radiation might underlie or exacerbate the liver toxicity of gefitinib. These are cytokines known to be released as a result of radiation (35, 36). However, we found that interleukin levels in general were low and that there was no correlation between them and ALT elevation. EGFR expression in immunohistochemistry results were seen in a significant proportion of patients. This is well in accord with previous reports (45). No cases of activated pEGFR were seen. A previous study reported pEGFR in 17% of cases, confirming the rarity of pEGFR in untreated hormone-sensitive disease (45). Also in parallel with previous work, EGFR amplification seems to be quite rare; we did not see any cases, while Schlomm et al. (20) reported amplification in 3.3% of patients. In contrast to a previous report, EGFRvIII was not seen in our study (46). We used a different antibody, which might partially explain the findings.
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Alternatively, patient ethnicity might play a role. Purely technical issues are unlikely to explain the lack of EGFRvIII in our analyses, as they were controlled with glioma specimens confirmed to be positive for EGFRvIII. CONCLUSIONS In summary, the overall safety of gefitinib in combination with prostate cancer radiotherapy appears to be acceptable, as less than 10% of patients had toxicity-related interruptions of radiotherapy. Liver enzyme elevations were frequently observed, but they were easily managed by temporarily interrupting gefitinib therapy. The preliminary efficacy of the combination seems quite promising compared to matched
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controls treated with a slightly higher biologically effective dose, but it is clear that the usual caveats of nonrandomized comparisons apply. For example, since controls were treated earlier, advances in treatment planning and delivery may have also played a role in improving treatment results. Efficacy of the combination can be studied reliably only in a randomized study. In addition to possibly increasing the disease control rate, the combination might also be useful for reducing side effects known to be associated with high (e.g., more than 72 Gy) radiation doses, if it allows efficacy to be maintained with a lower total dose. When considering a randomized phase III study to assess the efficacy of this approach, it is key to contemplate possible gains in efficacy versus increases in toxicity.
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