A dose-escalation and pharmacokinetic study of gemcitabine and oxaliplatin in patients with advanced solid tumors

Original article

Annals of Oncology 14: 304–312, 2003 DOI: 10.1093/annonc/mdg063

A dose-escalation and pharmacokinetic study of gemcitabine and oxaliplatin in patients with advanced solid tumors D. Mavroudis1, P. Pappas2, C. Kouroussis1, S. Kakolyris1, S. Agelaki1, K. Kalbakis1, N. Androulakis1, J. Souglakos1, N. Vardakis1, M. Nikolaidou2, G. Samonis1, M. Marselos2 & V. Georgoulias1* 1

Department of Medical Oncology, University General Hospital of Heraklion, Crete; 2Department of Pharmacology, Medical School, University of Ioannina, Ioannina, Greece Received 2 May 2002; revised 5 July 2002; accepted 18 July 2002

Background: Gemcitabine and oxaliplatin have broad antineoplastic activity and favorable toxicity. We

Introduction Gemcitabine (2′,2′-difluorodeoxycytidine, Gemzar; Eli Lilly, Indianapolis, IN, USA) is a novel nucleoside analog of deoxycytidine with a unique mechanism of action, favorable toxicity and broad spectrum antineoplastic activity in many solid tumors. Although inactive in the parental form, it is rapidly phosphorylated intracellularly to its active forms of gemcitabine diphosphate and gemcitabine triphosphate. Gemcitabine diphosphate inhibits ribonucleotide reductase [1], and gemcitabine triphosphate is incorporated into DNA resulting in DNA chain termination [2]. Gemcitabine has been licensed for the treatment of pancreatic and non-small-cell lung cancer (NSCLC), but also has shown

*Correspondence to: Dr V. Georgoulias, Department of Medical Oncology, University General Hospital of Heraklion, PO Box 1352, 71110 Heraklion, Crete, Greece. Tel: +30-81-392747; Fax: +30-81-392802; E-mail: [email protected] © 2003 European Society for Medical Oncology

significant activity in breast cancer, ovarian cancer, bladder cancer and head and neck cancer [3]. The recommended dose is 800–1250 mg/m2 administered intravenously (i.v.) weekly for 3 weeks followed by 1 week of rest. Due to its low toxicity, higher doses up to 2400 mg/m2 have been administered on a weekly schedule for 3 consecutive weeks in cycles every 4 weeks [4]. Gemcitabine causes short-lived myelosuppression, which is the dose-limiting toxicity (DLT), and mild transaminase increases, fever, rash, edema and flu-like symptoms. Gastrointestinal distress, renal toxicity and alopecia are uncommon [5]. Oxaliplatin (Eloxatin; Sanofi, Paris, France) is a new platinum derivative characterized by a 1,2-diaminocyclohexane carrier ligand, which confers important advantages in terms of activity and toxicity compared with cisplatin and carboplatin. Oxaliplatin lacks the nephrotoxicity of cisplatin and causes less myelosuppression than carboplatin, while it may be active in tumors with intrinsic or acquired resistance to cisplatin [6, 7]. This partial cross-resistance with cisplatin and carboplatin is presumably

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

conducted a phase I study to determine the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) of the combination in patients with advanced solid tumors. Patients and methods: Sixty-eight patients with advanced stage solid tumors were enrolled. Treatment was first-line for 35% of patients, second-line for 27%, and third-line for 38%. Gemcitabine was administered at escalating doses of 1000–2000 mg/m2 as a 30-min intravenous (i.v.) infusion on days 1 and 8 and oxaliplatin at 60–130 mg/m2 as a 4-h i.v. infusion on day 8 every 21 days without growth factor support. Results: The MTD was defined at gemcitabine 1800 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8. Twelve dose levels were evaluated and DLTs occurring during the first cycle consisted of grade 4 neutropenia, grade 3 asthenia or mucositis and grade 1–3 neutropenia or thrombocytopenia resulting in treatment delays. A total of 266 cycles were administered with only one episode of febrile neutropenia and no toxic deaths. Seven (3%) and 26 (10%) cycles were complicated by grade 4 and 3 neutropenia, respectively, three (1%) and 13 (5%) by grade 4 and 3 thrombocytopenia, and eight (3%) by grade 3 anemia. The most common non-hematological toxicity was grade 2/3 asthenia observed in 23% of cycles. Responses were observed in patients with a variety of epithelial neoplasms. The pharmacokinetic study revealed no significant interaction between the two drugs. Conclusions: The combination of gemcitabine and oxaliplatin has excellent tolerability and promising activity in patients with advanced solid tumors. As the MTD exceeds the recommended single-agent dose for gemcitabine, and a dose–response effect has not been established, we recommend using both drugs at full doses, e.g. gemcitabine 1200–1400 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8 for further phase II studies. Key words: gemcitabine, oxaliplatin, phase I, solid tumors

305

Patients and methods Patient selection Patients were eligible if they were 18–75 years of age and had histologically or cytologically confirmed advanced or metastatic solid tumors refractory to conventional therapy. Chemonaive patients with advanced tumors for whom no effective treatment existed were also eligible. Prior surgery, radiotherapy (to <25% of marrow-containing bones), or chemotherapy (maximum two prior regimens) was allowed, but a treatment-free interval of at least 4 weeks was required before study entry. Other inclusion criteria were as follows: WHO performance status of two or less; adequate blood counts (absolute neutrophil count >1500/µl, hemoglobin >10 g/dl and platelets >100 000/µl); adequate renal function (serum creatinine <2 mg/dl); adequate hepatic function (total bilirubin <1.5 mg/dl and alanine aminotransferase/aspartate aminotransferase <3 × upper normal limit); pre-existing peripheral neuropathy up to National Cancer Institute grade 1; and a life expectancy of at least 3 months. All patients signed a written informed consent before study entry.

Table 1. Treatment schedule and dose escalation Dose level

Gemcitabine (mg/m2), days 1 and 8

Oxaliplatin (mg/m2), day 8

1

1000

60

2

1200

70

3

1200

80

4

1400

80

5

1400

90

6

1600

90

7

1600

100

8

1600

110

9

1600

120

10

1600

130

11

1800

130

12

2000

130

The study was approved by the Ethics and Scientific Committees of our institution.

Treatment Treatment schedule and dose-escalation levels are shown in Table 1. Gemcitabine was administered as a 30-min i.v. infusion on days 1 and 8 at escalated doses ranging from 1000 to 2000 mg/m2. Oxaliplatin was administered on day 8, following gemcitabine administration, as a 4-h i.v. infusion, without pre- or post-hydration, at escalated doses ranging from 60 to 130 mg/m2. Treatment cycles were repeated every 3 weeks without prophylactic administration of hematopoietic growth factors. The ‘standard’ antiemetic regimen included ondansentron 16 mg, dexamethasone 8 mg and diazepam 5 mg given i.v. 30 min before chemotherapy administration. Hematological toxicity was followed with at least weekly complete blood counts, differential counts, and, in the case of grade 3/4 toxicity, daily counts until recovery. Blood chemistries, as well as a detailed toxicity questionnaire and a physical examination, were performed before each cycle. Toxicities were graded according to WHO criteria [14]. Day 1 and day 8 treatments were administered on scheduled dates without any delay or dose reduction if the laboratory inclusion criteria were met; otherwise, even for grade 1 toxicity, which did not meet the inclusion criteria, treatment of day 1 or day 8 was postponed for up to 7 days until resolution of the prohibitive toxicity. Then treatment was resumed according to the predefined schedule and dose and without any missed dose. If the prohibitive toxicity had not resolved after a 7-day treatment postponement, the scheduled treatment was missed and upon resolution of the toxicity, treatment was resumed as a new cycle using doses of the previous dose level. Doses were also reduced to the previous dose level in case of febrile neutropenia or platelet transfusion. In case of grade 3/4 neurotoxicity, treatment was discontinued and the patient was taken off study.

Dose escalation As shown in Table 1 the following 12 dose-escalation levels for gemcitabine/ oxaliplatin have been evaluated: 1000/60; 1200/70; 1200/80; 1400/80; 1400/90; 1600/90; 1600/100; 1600/110; 1600/120; 1600/130; 1800/130; 2000/130 (mg/m2). No intra-patient dose escalation was allowed. At least three patients were enrolled at each dose level. If a DLT was observed in one of the first three patients, then three additional patients were enrolled at the same dose level. DLTs were assessed during the first chemotherapy cycle. DLT was defined as the occurrence of any of the following: grade 4 hematological toxicity; grade 3/4 neutropenia with fever >38.2°C; grade 3/4 non-

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

attributable to a different mechanism of action or resistance, as demonstrated in a National Cancer Institute cytotoxicity screening study [8]. Oxaliplatin induces adducts that are more effective at inhibiting DNA synthesis and mechanisms of resistance include defects in mismatch repair and enhanced replicative bypass [6]. In clinical practice, oxaliplatin used alone or in combination with 5-fluorouracil (5-FU) and leucovorin has produced high response rates and long progression-free survival in patients with advanced colorectal cancer [9]. Although oxaliplatin is not licensed in the United States, it is approved in many European countries for the treatment of advanced colorectal cancer in combination with 5-FU and leucovorin. Oxaliplatin is also active in ovarian cancer, NSCLC, breast cancer, non-Hodgkin’s lymphomas and gastrointestinal tumors [10]. The recommended dose is 130 mg/m2 administered as a 2–6 h i.v. infusion every 3 weeks. Because of the lack of nephrotoxicity, oxaliplatin can be given without pre- or post-hydration. The DLT is dose-dependent and cumulative peripheral neuropathy, triggered or enhanced by exposure to cold, and manifested as paresthesia and dysesthesia in the extremities [11]. However, unlike the neurotoxicity typically seen with cisplatin administration, oxaliplatin’s neurotoxicity is reversible after discontinuation of treatment. Other toxicities are usually mild and uncommon. Hematological toxicity is limited to grade 1/2 neutropenia or thrombocytopenia even at doses up to 200 mg/m2 [12]. Nausea and vomiting can be easily controlled with standard antiemetic pretreatment, and diarrhea, alopecia and ototoxicity are uncommon. Growth inhibition studies using the human CEM leukemia cell line and the colon cancer cell lines HCT 116 and Colo 320 DM revealed that the gemcitabine–oxaliplatin combination displayed supra-additive effects and that the cytotoxic effects of the combination were better than or equal to those of gemcitabine– cisplatin combinations [13]. Based on the different mechanisms of action of the two drugs, the in vitro evidence of enhanced activity when combined together, the broad spectrum of antineoplastic activity with favorable non-overlapping toxicity, we conducted a dose-escalation and pharmacokinetic study to determine the maximum tolerated doses (MTD) and the DLTs of the combination in patients with advanced solid tumors.

306 hematological toxicity, excluding nausea/vomiting; and any treatment delay because of toxicity. Dose escalation was discontinued and the DLT dose level was reached if at least 50% of the patients treated at that level developed a DLT (e.g. at least two of three, or three of six patients). The MTD dose level was defined as the first level below the DLT dose level.

Pharmacokinetic methods

No. of patients (%) Patients enrolled

68

Evaluable for toxicity

68 (100)

Evaluable for response

56 (82)

Gender (male/female)

35/33 (51/49)

Performance status (WHO) 0

26 (38)

1

32 (47)

2

10 (15)

Number of previous regimens 0

24 (35)

1

18 (27)

2

26 (38)

Type of tumor Adenocarcinoma of unknown primary origin

14 (21)

Breast cancer

9 (13)

Non-small-cell lung cancer

8 (12)

Transitional cell carcinoma

7 (10)

Soft tissue sarcoma

5 (7)

Head and neck carcinomas

5 (7)

Other

20 (30)

NSCLC, transitional cell carcinomas, head and neck cancer and sarcomas as the most common types. Patient characteristics are shown in Table 2. Median age was 64 years; performance status (WHO) was one or less for 85% of the patients. Twenty-six patients (38%) had previously received two other chemotherapy regimens. All patients were evaluable for toxicity assessment.

Dose-limiting toxicities Tumor response Although patients were not required to have bidimensionally measurable disease to enter the study, response was assessed according to the standard WHO criteria for those who did [14]. Patients evaluable for response were the patients who had measurable disease and had completed at least two cycles of chemotherapy.

Statistical methods Differences of the nadir hematological parameters between cycles (cycle 1 versus cycle 3) and dose levels (1, 2, etc.) were examined by a two-way analysis of variance; this allowed also the assessment of an interaction effect between cycles and dose levels.

Results Between January 1998 and March 2000, 68 patients were enrolled in the study. Patients had a variety of neoplasms including adenocarcinomas of unknown primary origin, breast cancer,

Table 3 shows the dose-escalation levels, the number of patients enrolled at each level, and the observed DLTs during the first cycle. The most common DLT was grade 4 neutropenia observed in five patients at dose levels 4 (one patient), 5 (one patient), 9 (one patient) and 12 (two patients). Other DLTs included grade 3 (three patients) and grade 2 (two patients) neutropenia, and grade 2 (one patient) and grade 1 (one patient) thrombocytopenia; these toxicities were also considered DLTs because they resulted in treatment delays. Grade 3 asthenia (two patients) and grade 3 mucositis (one patient) as well as a grade 3 allergic reaction to gemcitabine (one patient), which occurred after the first administration, were also considered DLTs. At dose level 12, four out of eight patients (50% of patients enrolled) experienced a DLT during the first cycle of treatment; thus, this level was considered as the DLT dose level. At dose level 11, only one out of six patients enrolled developed a DLT, which was grade 2 neutropenia resulting in treatment delay on day 8; this level represented the MTD dose level of the combination.

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

The pharmacokinetic parameters of gemcitabine and oxaliplatin were assessed for 12 patients on day 8 of the first cycle at dose levels 6, 7, 8, 9, 10, 11 and 12. Samples from two patients were collected for each dose level except levels 6 and 7 where samples from only one patient were analyzed. For gemcitabine measurements blood samples were drawn in tubes containing tetrahydrouridine before starting and immediately following the end of the i.v. infusion and then at 1, 4, 8 and 24 h thereafter. A reversed-phase HPLC method was used to separate and quantify gemcitabine [15]; the chromatographic system (Shimadzu LC-10A/10Avp; Shimadzu Deutschland GmbH, Duisburg, Germany) consisted of an LC10AD pump, an SCL-10Avp controller, an SIL-10Avp automatic sample injector and an SPD-M10Avp UV detector. Calculation of gemcitabine concentration was based on a standard calibration curve using standard solutions of gemcitabine (Eli Lilly) with good linearity (r2 = 0.9996). The detection limit was determined as 0.078 mg/l of plasma. For oxaliplatin concentration measurements blood samples were drawn before starting, in the middle of, and immediately following the end of the i.v. infusion and then at 30 min, 1, 2, 4, 6 and 24 h thereafter. Aliquots for total oxaliplatin were diluted with 25% Triton X-100 and 20 µl were used for the measurement [16]. Ultrafiltrated samples (considered as oxaliplatin plasma fraction free from proteins) obtained by centrifugation at 2000 g for 30 min at –4°C using Centrex UF2 micropartition devices of 30 000 Da cut-off (Schleicher & Schuell, Dassel, Germany) were measured immediately after filtration without any preparation [16, 17]. Different oxaliplatin levels were determined by flameless atomic absorption spectrophotometry with deuterium correction, on a Shimadzu system of an AA-6800 spectrophotometer and a GFA-EX 7 graphite furnace at 265.9 nm. Standard platinum concentrations (FLUCA, Buchs, Switzerland) and a standard calibration curve (range 12.8– 96.0 µg/l, with good linearity, r2 = 0.9998), were used for calculation of oxaliplatin concentrations. All the within-day values of both free and total oxaliplatin were less than 7%. All pharmacokinetic calculations were made according to Human Drug Kinetics (Saunders L, Ingram D, Jackson SHD Eds, IRL Press, Oxford, UK, 1989), and by using PRISM (v2.0) GraphPad Software (PRISM, San Diego, USA).

Table 2. Patient characteristics [mean age 64 years (range 30–75)]

307 Table 3. Dose-escalation levels, number of patients enrolled, and dose-limiting toxicities (DLTs) observed Gemcitabine (mg/m2)

Dose level

Oxaliplatin (mg/m2)

No. of patients

DLT (No. of patients)

1

1000

60

3 (3)a

–

2

1200

70

3 (3)

–

3

1200

80

6 (4)

Grade 3 asthenia (1)

4

1400

80

6 (5)

Grade 4 neutropenia (1) Grade 3 neutropeniab (1)

5

1400

90

6 (5)

Grade 4 neutropenia (1) Grade 3 asthenia (1)

1600

90

6 (3)

Grade 3 neutropeniab (1)

7

1600

100

6 (3)

Grade 1 thrombocytopeniab (1)

8

1600

110

6 (2)

Grade 2 neutropeniab (1)

9

1600

120

6 (4)

Grade 4 neutropenia (1)

10

1600

130

6 (2)

Grade 3 neutropeniab (1) Grade 3 mucositis (1)

11

1800

130

6 (3)

Grade 2 neutropeniab (1)

12

2000

130

8 (7)

Grade 4 neutropenia (2) Grade 2 thrombocytopeniab (1) Grade 3 allergic reaction (1)

a

Number of patients who had previously received ≥1 chemotherapy regimen. Denotes that the toxicity was considered a DLT because it resulted in treatment delay.

b

Table 4. Hematological toxicity (WHO grade 2–4) of the gemcitabine–oxaliplatin combination in all cycles and per first course by dose level. Values are number of all cycles, and in parentheses the number of first cycles Dose level

No. of cycles

Neutropenia

Anemia

Grade 2

Grade 3

1

11

3 (1)

1 (0)

0 (0)

Grade 4

2

12

0 (0)

1 (0)

3

28

0 (0)

1 (0)

4

16

1 (1)

5

21

5 (1)

6

28

7

19

8 9

Grade 2

Thrombocytopenia Grade 3

Grade 4

Grade 2

Grade 3

5 (1)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

Grade 4

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

1 (0)

0 (0)

0 (0)

11 (3)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

3 (2)

1 (1)

5 (1)

0 (0)

0 (0)

2 (1)

0 (0)

0 (0)

1 (0)

1 (1)

5 (2)

0 (0)

0 (0)

4 (2)

3 (0)

0 (0)

4 (1)

2 (1)

0 (0)

6 (2)

2 (1)

0 (0)

0 (0)

2 (1)

0 (0)

0 (0)

0 (0)

0 (0)

4 (2)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

21

5 (2)

3 (1)

0 (0)

1 (1)

0 (0)

0 (0)

1 (0)

0 (0)

0 (0)

29

2 (0)

3 (0)

3 (1)

10 (1)

0 (0)

0 (0)

0 (0)

2 (0)

0 (0)

10

26

2 (0)

5 (1)

0 (0)

11 (4)

2 (0)

0 (0)

4 (1)

0 (0)

1 (0)

11

28

7 (1)

3 (0)

0 (0)

8 (3)

4 (0)

0 (0)

3 (0)

2 (0)

2 (0)

12 Total

27

4 (1)

3 (0)

2 (2)

5 (4)

0 (0)

0 (0)

2 (1)

3 (0)

0 (0)

266

33 (8)

26 (5)

7 (5)

71 (24)

8 (1)

0 (0)

16 (5)

13 (1)

3 (0)

Hematological and non-hematological toxicity A total of 266 cycles of treatment were administered, with a median of three cycles/patient (range 1–10 cycles). The median interval between cycles was 22 days (range 21–35). Sixty-three cycles (24%) were delayed because of hematological toxicity (32 cycles), non-hematological toxicity (six cycles), or for reasons unrelated to the disease or treatment (25 cycles), i.e. pending

imaging studies for response evaluation. Table 4 shows the hematological toxicity observed in all chemotherapy cycles as well as per first chemotherapy courses at the different dose levels. A total of 26 (10%) and seven (3%) cycles corresponding to 20 (29%) and six (9%) patients were complicated by grade 3 and 4 neutropenia, respectively; 13 (5%) and three (1%) cycles or 11 (16%) and three (4%) patients by grade 3 and 4 thrombocytopenia; and eight (3%) cycles or four (6%) patients by grade 3

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

6

308 Table 5. Non-hematological toxicity (WHO grade 2/3) of the gemcitabine–oxaliplatin combination in all cycles and per first course by dose level. Values are number of all cycles, and in parentheses the number of first cycles Dose level

No. of cycles

Vomiting Grade 2

Diarrhea

Astheni

Grade 2

Grade 2

Grade 3

4 (0)

2 (0)

Grade 2

Grade 3

2 (1)

0 (0)

0 (0)

0 (0)

1 (0)

0 (0)

2 (0)

0 (0)

2

12

1 (1)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

3

28

2 (0)

0 (0)

1 (1)

0 (0)

0 (0)

0 (0)

1 (0)

0 (0)

12 (2)

2 (1)

4

16

1 (1)

0 (0)

0 (0)

0 (0)

1 (1)

0 (0)

0 (0)

0 (0)

2 (0)

0 (0)

5

21

3 (1)

0 (0)

2 (1)

0 (0)

0 (0)

0 (0)

0 (0)

1 (0)

9 (3)

1 (1)

6

28

0 (0)

0 (0)

1 (1)

0 (0)

1 (0)

0 (0)

3 (0)

0 (0)

3 (2)

2 (0)

7

19

3 (2)

0 (0)

1 (1)

0 (0)

0 (0)

0 (0)

2 (0)

1 (0)

5 (1)

0 (0)

8

21

0 (0)

1 (0)

1 (1)

0 (0)

0 (0)

0 (0)

2 (0)

0 (0)

1 (0)

2 (0)

9

29

7 (1)

1 (0)

1 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

2 (1)

0 (0)

10

26

2 (1)

1 (1)

2 (1)

1 (0)

0 (0)

1 (1)

0 (0)

0 (0)

3 (0)

0 (0)

11

28

3 (0)

0 (0)

1 (0)

0 (0)

0 (0)

0 (0)

2 (0)

0 (0)

2 (0)

2 (0)

27

2 (1)

1 (0)

0 (0)

0 (0)

0 (0)

0 (0)

2 (0)

0 (0)

4 (0)

1 (1)

266

26 (9)

4 (1)

10 (6)

1 (0)

3 (1)

1 (1)

14 (0)

2 (0)

47 (9)

14 (3)

anemia. Only one episode of febrile neutropenia was observed at dose level 10. Six episodes of non-neutropenic infections occurred in five patients and responded promptly to antibiotics. No bleeding episodes have been noted, and there have been no toxic deaths. No significant differences among the dose-escalation levels in the nadir counts were noted (analysis of variance: neutrophils P = 0.40, hemoglobin P = 0.20, platelets P = 0.07). Furthermore no increased cumulative hematological toxicity was observed between cycles 1 and 3 (analysis of variance: neutrophils P = 0.20, hemoglobin P = 0.90, platelets P = 0.50) (data not shown). Non-hematological toxicity was generally mild. Table 5 shows the non-hematological toxicity in all cycles and per first courses at the different dose levels. Across all dose levels the most common toxicity was asthenia, which was grade 2 in 47 cycles (18%) corresponding to 21 patients (31%) and grade 3 in 14 cycles (5%) corresponding to 11 patients (16%). Similarly, grade 2 peripheral sensory neurotoxicity was observed in 14 cycles (5%) corresponding to six patients (9%) and grade 3 in two cycles (1%) corresponding to two patients (3%). Grade 3 vomiting, diarrhea and mucositis were rarely seen. Grade 1/2 edema and transient maculopapular rash were observed in 14 (21%) and eight (12%) patients, respectively. A flu-like syndrome was reported by eight patients (12%) in 10 cycles (4%). Onycholysis was observed in five patients (7%).

Treatment delivery The percentage of doses administered on day 8 as well as the median delivered dose intensity and the intended dose intensity for the 12 dose-escalation levels are shown in Table 6. Overall, dose reduction was required in 18 patients (26%) or 22 cycles (8%) due to hematological (16 cycles) and non-hematological (six cycles) toxicity. All but one patient have discontinued treatment for the following reasons: progressive disease (40 patients),

Grade 3

achievement of maximum response (16 patients), toxicity (eight patients) and refusal of further treatment (three patients). The median cumulative administered dose for gemcitabine was 9808 mg/m2 (range 1562–28800) and for oxaliplatin 329 mg/m2 (range 70–1040).

Pharmacokinetic results The pharmacokinetic parameters for both gemcitabine and oxaliplatin at the different dose levels are shown in Table 7. Representative concentration versus time curves for oxaliplatin and gemcitabine are shown in Figure 1. The levels of gemcitabine maximum concentrations as well as area under the curve (AUC), clearance (CL) and half-life (t½) were similar to previously reported data for patients receiving either a lower dose with the same infusion rate [15] or a proportional range of doses with different infusion rates [18]. The Cmax of gemcitabine was 30.3 mg/l (101.2 µmol/l) and it was detected at the dose of 1600 mg/m2 (Table 7). The maximum concentrations for all doses were detected at the end of the infusion. Gemcitabine concentrations ranged from 1.2 to 30.3 mg/l at the different dose levels and the mean concentration for all dose levels was 9.2 mg/l. The mean plasma AUC was 12.3 mg·h/l (range 4.2–28.1) and the mean CL was 344.4 l/h (range 87.7–706.7) (Table 7). The calculated mean t½ value was 0.26 h (or 15.6 min), and at 1 h after infusion only 3–14% of Cmax was detectable. For oxaliplatin the proportion of free drug ranged from 9% to 17% of the total drug at all dose levels. At the end of the 4-h oxaliplatin infusion the obtained Cmax in the ultrafiltrated fraction (free drug) was 0.35 mg/l at dose level 11 (Table 7), and in the plasma (total drug) 3.62 mg/l at dose level 10 (data not shown). The variation of within-day determinations for both free and total oxaliplatin concentrations were almost the same as previously reported [19]. Large interindividual variations were observed for both free and total drug levels. The mean ± standard deviation

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

Grade 3

11

Total

Grade 2

Neurotoxicity

1

12

Grade 3

Mucositis

309 Table 6. Treatment delivery on day 8 Dose level

No. of cycles

Gemcitabine

Oxaliplatin

Percent of doses administered

Median delivered dose intensity (mg/m2/week)a

Percent of doses administered

Median delivered dose intensity (mg/m2/week)a

1

11

100

300 (90)

100

18 (90)

2

12

100

379 (95)

100

22 (96)

3

28

96

4

16

100

5

21

90

372.5 (93) 441.5 (94.5) 404 (86.5)

96

24.5 (91)

100

24.5 (91)

90

25.5 (84.5)

28

96

461 (88)

96

27 (90)

19

95

533 (100)

89

33 (100)

8

21

100

512.5 (96)

100

35 (96)

9

29

100

492.5 (92.5)

100

36.5 (94)

10

26

100

489 (92)

100

39 (91)

11

28

100

540 (90)

100

39 (90)

12

27

81

81

33 (66)

a

542 (81%)

In parentheses the corresponding percentage of the intended dose intensity.

Table 7. Pharmacokinetic parameters Dose level 6

7

8

9

10

11

12

1

1

2

2

2

2

2

Cmax (mg/l)

0.13

0.12

0.19/0.31

0.13/0.14

0.09/0.18

0.29/0.35

0.16/0.24

AUC (mg·h/l)

2.1

1.9

2.5/6.3

1.5/1.6

0.6/3.1

3.7/6.6

0.6/2.5

82.3

82.1

27.0/70.6

122.9/143.7

75.2/382.6

34.7/60.8

92.8/342.0

7.6

13.5

5.6/19.8

6.2/13.4

9.5/12.9

1.0/7.5

No. of patients Oxaliplatin

a

CL (l/h) t½ (h)

4.0/17.1

Gemcitabine Cmax (mg/l) AUC (mg·h/l) CL (l/h) t½ (h)

1.18 4.25 706.7 0.34

2.69

30.34b

nd

5.99/8.05

8.99b

3.11/6.96

9.58

b

nd

5.29/14.22

13.98b

7.17/9.22

255.6 0.28

28.06 87.7

b

0.21b

nd

202.5/538.7

nd

0.20/0.23

225.3

b

0.27b

394.8/446.3 0.23 /0.24

a

Ultrafiltrated fraction/free drug. Determination was performed in sample from one patient. AUC, area under the curve; CL, clearance; Cmax, maximal drug concentration; nd, not determined; t½, half-life.

b

values of elimination t½ and AUC (9.8 ± 5.3 h and 2.8 ± 1.9 mg·h/l, respectively) were within the reported ranges by other investigators [16]. The clearance of the ultrafiltrated fraction was relatively high, ranging from 47.8 to 228.9 l/h with a very high standard deviation value (Table 7; 126.4 ± 110.2 l/h). Based on the above measurements, the pharmacokinetic profile of both drugs does not seem to be modified when the two drugs are administered concomitantly according to the schedule evaluated in the present study.

Antitumor activity Twelve patients were not evaluable for response for the following reasons: lack of bidimensionally measurable disease (n = 7),

treatment discontinuation after the first cycle (n = 3), lost to follow-up (n = 2). Among 56 patients who were evaluable for response, we observed 10 with partial response, 16 with stable disease and 30 with progressive disease. Responses were observed at dose levels 1, 2, 6, 10, 11 and 12 including two patients with breast cancer (third-line treatment), two patients with bladder cancer (second-line treatment), two patients with adenocarcinoma of unknown primary (first-line treatment), one patient with NSCLC (third-line treatment) and one patient with each of the following: endometrial cancer, fallopian tube cancer and carcinoid tumor of the intestine (all first-line treatment). The median duration of response was 3.5 months (range 1.5–17.5) and the median time to tumor progression was 5.5 months (range 4–19).

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

6 7

310

Discussion In a previous report based on the preliminary results of this phase I study we suggested that gemcitabine and oxaliplatin could be efficiently combined in a low-toxicity regimen with doses equal to or near monotherapy levels [20]. This final report of the doseescalation study includes results from 20 additional patients entered in three further escalated dose levels, and reports toxicity data including 113 additional cycles of treatment. Our final results reinforce our initial observations that the combination of gemcitabine and oxaliplatin is a very well-tolerated regimen even at higher than monotherapy doses and by patients treated previously with chemotherapy. Furthermore, although it was not a primary objective of this study, we have seen encouraging responses in heavily pretreated patients with resistant tumors or patients with tumors that are typically refractory to chemotherapy. Therefore this regimen is suitable for further testing in phase II trials to determine its activity and palliation potential in patients with various types of advanced tumors. Since the purpose of our study was to determine the MTD and DLT of the combination, doses of both drugs were escalated based on the predefined study criteria. Based on these the DLT dose level was reached if at least 50% of the patients treated at that level developed a DLT (e.g. at least two of three, or three of six patients). This is a liberal and arbitrarily defined criterion

used in many studies and has obvious shortcomings since it accepts a DLT incidence of up to 49%. The MTD was reached at gemcitabine 1800 mg/m2 administered on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8 every 21 days. These doses are considered to be ‘tolerable’ based on the predefined study criteria for DLTs encountered during the first cycle of treatment. For oxaliplatin this represents the recommended dose for single-agent administration and for gemcitabine it exceeds the monotherapy recommended dose. Although we did not observe any cumulative effect on either hematological or non-hematological toxicity even at the higher dose levels (data not shown), we cannot recommend the MTD doses to be used in future phase II trials since a dose–response effect has not been established for any of the used agents and the responses observed in our study occurred across all dose levels. However, based on our results, the administration of both agents at full doses, e.g. gemcitabine 1200–1400 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8, should be well tolerated and represent our recommendation for further phase II testing. The observed low toxicity of this regimen was expected since both drugs have very favorable toxicity profiles and present different DLTs [5, 11]. Therefore the low amount of toxicity observed in this study can be explained by the mild and nonoverlapping toxicities of the individual agents. The good

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

Figure 1. Representative concentration versus time curves for oxaliplatin (A) and gemcitabine (B).

311 combination with other active agents such as gemcitabine may be preferable to cisplatin combinations for the treatment of NSCLC and deserve evaluation in phase II studies. Finally, because loss of DNA mismatch repair results in resistance to cisplatin but not to oxaliplatin [30], and because oxaliplatin is active in cisplatinresistant as well as cisplatin-sensitive tumors [31], oxaliplatinbased combinations should be tested in platinum-sensitive and -resistant neoplasms. In a recently published phase II study of the combination in patients with advanced pancreatic adenocarcinoma, gemcitabine was administered at 1000 mg/m2 as a 10 mg/m2/min infusion on day 1 and oxaliplatin at 100 mg/m2 on day 2 in cycles every 2 weeks [32]. Only 11% of patients developed each of grade 3/4 neutropenia, thrombocytopenia and peripheral neuropathy and the overall response rate was 30%. Although using a different administration schedule than our study, these results confirm our findings regarding the promising activity and favorable toxicity of this combination. To the best of our knowledge this is the first dose-escalation and pharmacokinetic study reported for the gemcitabine–oxaliplatin combination. In this study the combination was evaluated extensively in terms of toxicity in a large cohort of patients receiving many cycles of treatment across a wide range of doses. Based on the observed excellent tolerability and promising activity, this regimen deserves further testing in phase II trials in various types of tumors. Although higher doses may be well tolerated, the recommended doses are gemcitabine 1200–1400 mg/m2 on days 1 and 8 and oxaliplatin 130 mg/m2 on day 8 without growth factor support or prophylactic antibiotic administration.

Acknowledgements This work was supported in part by the Cretan Association for Biomedical Research (CABR); D. Mavroudis was a recipient of a CABR scholarship.

References 1. Heinemann V, Xu YZ, Chubb S et al. Inhibition of ribonucleotide reduction in CCRF-CEM cells by 2′,2′-difluorodeoxycytidine. Mol Pharmacol 1990; 38: 567–572. 2. Huang P, Chubb S, Hertel LW et al. Action of 2′,2′-difluorodeoxycytidine on DNA synthesis. Cancer Res 1991; 51: 6110–6117. 3. Carmichael J. The role of gemcitabine in the treatment of other tumours. Br J Cancer 1998; 78 (Suppl 3): 21–25. 4. Fossella FV, Lippman SM, Shin DM et al. Maximum-tolerated dose defined for single-agent gemcitabine: a phase I dose-escalation study in chemotherapy-naive patients with advanced non-small-cell lung cancer. J Clin Oncol 1997; 15: 310–316. 5. Green M. Gemcitabine safety overview. Semin Oncol 1996; 23 (Suppl 10): 32–35. 6. Raymond E, Faivre S, Woynarowski J et al. Oxaliplatin: mechanism of action and antineoplastic activity. Semin Oncol 1998; 25 (Suppl 5): 4–12. 7. Chollet P, Bensmaine A, Brienza S et al. Single agent activity of oxaliplatin in heavily pretreated advanced epithelial ovarian cancer. Ann Oncol 1996; 7: 1065–1070. 8. Rixe O, Ortuzar W, Alvarez M et al. Oxaliplatin, tetraplatin, cisplatin, and carboplatin: Spectrum of activity in drug-resistant cell lines and in

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

tolerance of the regimen is especially important in view of the characteristics of the study population (median age 64 years; 38% of patients had two prior regimens). Despite these adverse parameters, clinically significant grade 3/4 neutropenia and thrombocytopenia complicated 13% and 6% of the treatment cycles overall, and less than 25% and 15% of the cycles at any dose level, respectively. Moreover, there was only one episode of febrile neutropenia observed at dose level 10. Although neutropenia was the most common dose-limiting event, asthenia was the most common non-hematological toxicity complicating approximately one-quarter of the treatment cycles. The observed low incidence of peripheral sensory neurotoxicity may be attributable to the relatively low cumulative oxaliplatin dose (median cumulative administered dose for oxaliplatin 329 mg/m2). It has been reported that nearly all patients are expected to experience some degree of neurosensory toxicity at cumulative oxaliplatin dose levels of ≥540 mg/m2 [11]. However, this neurotoxicity is also reported to be highly reversible, as 82% of patients have their neuropathy regress within 4–6 months, and 41% experience complete recovery within 6–8 months. In our study neurotoxicity reversed in four out of five evaluable patients after 3–6 months of follow-up. This recovery is in contrast with the cisplatin-induced neuropathy, which usually tends to progress after treatment without signs of reversibility [21]. All pharmacokinetic parameters measured in the present study were dose-independent. This may be due to the large interindividual variation observed with both drugs. The obvious explanation for this is the small number of patients tested and the substantial variability that exists between different individual patients. We made every effort to avoid technical problems (e.g. blood sampling, problems with assays) associated with drug concentration measurements. Alternatively, the investigation of a wider range of doses may be necessary in order to demonstrate a dose-dependent correlation of pharmacokinetic parameters. Indeed, Abbruzzese et al. [15] reported a proportional increase of both Cmax and AUC of gemcitabine in the dose range of 53– 1000 mg/m2. Moreover, Graham et al. [22] reported increased values for plasma Cmax and AUC of oxaliplatin in a dose-related manner for doses ranging from 20 to 180 mg/m2. Since samples were analyzed for a limited number of patients for each dose level, the pharmacokinetic data of our study should be interpreted with caution. Therefore the unusually high AUC observed in dose levels 8 and 11 for both oxaliplatin and gemcitabine may be explained by the small number of patients tested. Since this was not observed in the other dose levels it is unlikely to represent interaction between the two drugs in terms of their pharmacodynamics. Our preliminary conclusion, based on these data, is that the pharmacokinetic profile of both drugs does not seem to be modified when the two drugs are administered concomitantly according to the schedule evaluated in this trial. In previous studies, both gemcitabine and oxaliplatin have shown single-agent activity in refractory neoplasms such as breast cancer, ovarian cancer, bladder cancer, germ cell tumors and lymphomas [23–28]. Furthermore, oxaliplatin was shown to have comparable activity but with a better toxicity profile than cisplatin in poor-prognosis NSCLC patients [29]. Therefore, its

312

9. 10. 11. 12. 13.

14.

16.

17.

18.

19. 20.

21.

the treatment of advanced ovarian cancer: Toxicity, efficacy results. Proc Am Soc Clin Oncol 1997; 16: 354a (Abstr 1266). 22. Graham M, Lockwood G, Greenslade D et al. Clinical pharmacokinetics of oxaliplatin: a critical review. Clin Cancer Res 2000; 6: 1205–1218. 23. Garufi C, Nistico C, Brienza S et al. Single-agent oxaliplatin in pretreated advanced breast cancer: a phase II study. Ann Oncol 2001; 12: 179–182. 24. Shapiro JD, Millward MJ, Rischin D et al. Activity of gemcitabine in patients with advanced ovarian cancer: responses seen following platinum and paclitaxel. Gynecol Oncol 1996; 63: 89–93. 25. Piccart MJ, Green JA, Lacave AJ et al. Oxaliplatin or paclitaxel in patients with platinum-pretreated ovarian cancer: a randomised phase II study of the European Organization for Research and Treatment of Cancer Gynecology Group. J Clin Oncol 2000; 18: 1193–1202. 26. Lorusso V, Pollera CF, Antimi M et al. A phase II study of gemcitabine in patients with transitional cell carcinoma of the urinary tract previously treated with platinum. Eur J Cancer 1998; 34: 1208–1212. 27. Einhorn LH, Stender MJ, Williams SD. Phase II trial of gemcitabine in refractory germ cell tumors. J Clin Oncol 1999; 17: 509–511. 28. Germann N, Brienza S, Rotarski M et al. Preliminary results on the activity of oxaliplatin (L-OHP) in refractory/recurrent non-Hodgkin’s lymphoma patients. Ann Oncol 1999; 10: 351–354. 29. Monnet I, Brienza S, Hugret F et al. Phase II study of oxaliplatin in poorprognosis non-small cell lung cancer (NSCLC). Eur J Cancer 1998; 37: 1124–1127. 30. Nehme A, Baskaran R, Nebel S et al. Induction of JNK and c-Abl signalling by cisplatin and oxaliplatin in mismatch repair-proficient and -deficient cells. Br J Cancer 1999; 79: 1104–1110. 31. Raymond E, Lawrence R, Izbicka E et al. Activity of oxaliplatin against human tumor colony-forming units. Clin Cancer Res 1998; 4: 1021– 1029. 32. Louvet C, Andre T, Lledo G et al. Gemcitabine combined with oxaliplatin in advanced pancreatic adenocarcinoma: final results of a GERCOR multicenter phase II study. J Clin Oncol 2002; 20: 1512–1518.

Downloaded from http://annonc.oxfordjournals.org/ at Dalhousie University on June 25, 2015

15.

the cell lines of the National Cancer Institute’s Anticancer Drug Screen panel. Biochem Pharmacol 1996; 52: 1855–1865. Bleiberg H. Oxaliplatin (L-OHP): a new reality in colorectal cancer. Br J Cancer 1998; 77 (Suppl 4): 1–3. Cvitkovic E. Ongoing and unsaid on oxaliplatin: the hope. Br J Cancer 1998; 77 (Suppl 4): 8–11. Extra JM, Marty M, Brienza S et al. Pharmacokinetics and safety profile of oxaliplatin. Semin Oncol 1998; 25 (Suppl 5): 13–22. Extra JM, Espie M, Calvo F et al. Phase I study of oxaliplatin in patients with advanced cancer. Cancer Chemother Pharmacol 1990; 25: 299–303. Faivre S, Raymond E, Woynarowski JM et al. Supraadditive effect of 2′,2′-difluorodeoxycytidine (gemcitabine) in combination with oxaliplatin in human cancer cell lines. Cancer Chemother Pharmacol 1999; 44: 117–123. Miller AB, Hoogstraten BB, Staquet M et al. Reporting results of cancer treatment. Cancer 1981; 47: 207–214. Abbruzzese JL, Grunewald R, Weeks EA et al. A phase I clinical, plasma, and cellular pharmacology study of gemcitabine. J Clin Oncol 1991; 9: 491–498. Massari C, Brienza S, Rotarski M et al. Pharmacokinetics of oxaliplatin in patients with normal versus impaired renal function. Cancer Chemother Pharmacol 2000; 45: 157–164. Wasserman E, Cuvier C, Lokiec F et al. Combination of oxaliplatin plus irinotecan in patients with gastrointestinal tumors: results of two independent phase I studies with pharmacokinetics. J Clin Oncol 1999; 17: 1751–1759. Grunewald R, Kantarjian H, Du M et al. Gemcitabine in leukemia: a phase I clinical, plasma, and cellular pharmacology study. J Clin Oncol 1992; 10: 406–413. Kern W, Braess J, Bottger B et al. Oxaliplatin pharmacokinetics during a four-hour infusion. Clin Cancer Res 1999; 5: 761–765. Mavroudis D, Kourousis Ch, Kakolyris S et al. Phase I study of the gemcitabine/oxaliplatin combination in patients with advanced solid tumors: a preliminary report. Semin Oncol 2000; 27 (1 Suppl 2): 25–30. Misset JL, Chollet PH, Vennin PH et al. Multicentric phase II–III trial of oxaliplatin versus cisplatin both in association with cyclophosphamide in