A phase I and pharmacologic study of DMP 840 administered by 24-hour infusion*

Annals of Oncology 9: 101-104, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands.

Short report A phase I and pharmacologic study of DMP 840 administered by 24-hour infusion* S. O'Reilly,1 S. D. Baker,1'2 S. Sartorius,1 E. K. Rowinsky,1'2 M. Finizio,3 G. M. Lubiniecki,1 L. B. Grochow,1 J. E. Gray,3 H. I Pieniaszek Jr3 & R. C. Donehower1 l

The Johns Hopkins Oncology Center, Baltimore, MD; 2 Present address: Cancer Therapy and Research Center, Institutefor Drug Development, San Antonio, TX; 3The Dupont Merck Pharmaceutical Co., Wilmington, DE, USA Summary Purpose: DMP 840, a novel bisnaphthalimide, has demonstrated promising schedule dependent anti-tumor activity in vitro and in vivo against several tumor cell lines. A phase I study was conducted to evaluate the effect of a 24-hour infusion schedule repeated every three weeks, on the therapeutic efficacy of DMP 840. Patients and methods: Fourteen patients with refractory solid tumor malignancies were treated with DMP 840 at doses of 20, 40, 50 and 60 mg/m2. Results: A combination of neutropenia, thrombocytopenia and stomatitis were dose-limiting at doses of 50 and 60 mg/m2 in both minimally- and extensively-pretreated patients. In con-

Background DMP 840, a novel bisnaphthalimide antitumor agent, was developed after bisnaphthalene-sulfonamide compounds demonstrated activity in screening tests for protein kinase C inhibitors [1]. Potent preclinical antitumor activity was observed in preclinical testing, with activity against over 50% of assessed tumor specimens exposed to drug concentrations of 100 ng/ml or greater in in vitro assays [2]. In initial phase I studies of this agent several short infusion schedules were evaluated [35]. In all of these studies myelosuppression and stomatitis were dose limiting. In the present study, the use of a more prolonged infusion schedule was investigated to assess the effect of infusion duration on the toxicity and pharmacokinetics of DMP 840.

Patients and methods Eligibility Only patients with histologically documented solid tumor malignancies refractory to conventional therapy or for which no effective therapy existed were candidates for this study. Eligibility criteria for the study included: 1) age > 18 years; 2) an Eastern Cooperative

trast, all courses at lower dose levels were well tolerated. Pharmacokinetic analysis demonstrated that DMP 840 had a prolonged terminal half life (median 39 hours; range 25-86) and that dose-limiting events were significantly related to several indices of systemic DMP 840 exposure (P < 0.01, Wilcoxon Rank Sum test). Conclusion: The recommended dose of DMP 840 for further disease oriented evaluations is 40 mg/m2 administered over 24 hours every three weeks. The infusion duration evaluated in this study did not result in a substantial increase in the tolerable dose compared to shorter, less cumbersome schedules. Key words: DMP 840, pharmacodynamics, pharmacokinetics, phase I

Oncology Group (ECOG) performance status of two or greater (ambulatory and capable of self care); 2) a life expectancy of at least eight weeks; 3) no major surgery within 14 days or wide field radiotherapy and/or chemotherapy within 28 days of entering onto protocol (or at least six weeks in those treated with a nitrosourea or mitomycin); and 4) adequate hematopoietic (white blood cell count >4000/ul and platelet count > 100,000/ul), hepatic (total bilirubin < 1.5 mg/dl) and renal (creatinine < 2.0 mg/dl) functions. Written informed consent was obtained before treatment.

Dosage The starting dose of DMP 840 was selected based on results from previous studies [5]. This dose was 20 mg/m2 administered by 24-hour continuous infusion to cohorts of three patients, with subsequent dose escalation to 40, and 60 mg/m2. Subsequently, as dose-limiting events were observed a dose of 50 mg/m2 was evaluated. The maximum tolerated dose (MTD) was defined as one dose level below that dose in which dose-limiting toxicities (DLTs) occurred in 50% of newly treated patients. DLTs were defined as either: 1) absolute neutrophil count (ANQ <500/ul for more than five days; 2) ANC < 500/ul with fever requiring parenteral antibiotics; 3) platelet count <50,000/ul and/or 4) non-hematologic toxicity > grade 3 National Cancer Institute (NCI) Common Toxicity Criteria [6]. Dose escalations were permitted in the same patient provided they had received at least one course at a lower dose level without DLT and if subsequent drug naive patients had tolerated one course at the higher dose level. Dose reductions, by one dose level, were performed for patients experiencing DLT.

* Presented in part at the 31st Annual Meeting of the American Society of Clinical Oncology, Los Angeles, CA, USA, 20-23 May 1995.

102 Table 1. Hematologic toxicity. DMP 840 No. ofpts dose evaluable/ mg/m2 total

20 40 50 60 a b

4/4 4/4 5/5 4/4

No. of courses evaluable/ total

Nadir HCT mean range (+/-SD)

Nadir platelet Grade thrombocount (K/ul) cytopenia mean (+/-SD) 0 1 2 3 4

11/11 10/10 5/6 7/7

34 (4.7) 32.5(3.4) 34 (1.5) 30.4(2.3)

257(50) 209(44) 221(118) 156(72)

11 9 4 6

0 0 0 0

0 0 0 0

0 0 1 0 0 1 0 1

Nadir ANC/ul mean (+/-SD)

Grade of neutropenia

4472(1536) 2355(994) 1214(1097) 923(683)

10 1 0 8 0 0 1 1 0 0 1 0

0

1 2

3 4

0 0 1 1 0 3 4 1

Dose limiting toxicity course/ total a - b

Dose limiting toxicity pts/total a>b

0/11 0/10 3/5 b 2/4

0/4 0/4 3/5b 2/4

Dose limiting events were only observed during course 1 of treatment. Both hematologic and non-hematologic dose limiting toxicities are listed.

Drug administration DMP 840 was supplied by the DuPont Merck Pharmaceutical Company (Wilmington, DE) in vials containing 30 mg of preservative free, lyopholized DMP 840. Each vial was initially reconstituted with 30 ml of 5% mannitol for injection to yield a final solution of concentration less than 0.5 mg/ml. Solutions were further dissolved in 5% mannitol solution to yield a solution of final concentration between 0.1 and 0.5 mg/ml. Polyolefin bags and infusion sets were used for chemotherapy administration. All tubing and solutions were wrapped in aluminium foil. All doses were administered via central venous access.

successful, were included in a subsequent iterative 2 stage analysis. This analysis provided individual pharmacokinetic parameter estimates and a population model which were then used to estimate parameters for the remaining six patients. The relationships between DMP 840 systemic exposure (C max , area under the plasma concentration versus time curve (AUC), and the times plasma concentrations were above 100, 50, and 10 ng/ml) and toxicity were explored using scatterplots. The Wilcoxon rank sum test was used to compare values for parameters of systemic exposure between those patients who experienced DLT, and those who did not. Statistical analysis was performed using the Statistica 5.0 software program (Statsoft, Tulsa, OK).

Pretreatment and follow up studies Histories, physical examinations, and routine laboratory studies were performed pretreatment and weekly. Complete blood counts were every other day if the ANC decreased to <500/ul. Toxicities were evaluated according to the NCI Common Toxicity Criteria. For the analysis of toxicity, patients were considered extensively pretreated with therapies that may affect long-term hematopoietic function if they had received wide field radiation therapy to >25% of bone marrow bearing bones [7], or ^ 6 courses of chemotherapy containing an alkylating agent or 5 2 courses of a nitrosourea or mitomycin. Formal tumor measurements were performed after every two courses of therapy, and patients were able to continue treatment if they did not develop progressive disease. Responses were evaluated according to standard ECOG criteria.

DMP 840 sampling and assay During course 1 of treatment blood samples were collected in heparinized tubes before chemotherapy administration; and for up to 72 hours after the end of infusion. These samples were centrifuged and the harvested plasma was stored at -20 °C until assayed. DMP 840 levels were quantified by high performance liquid chromatography assay using ultraviolet detection at 274 nm as described previously [8]. The lower limit of quantification was 10 ng/ml. The intraday and interday precisions ranged from 2.7%-8.6% and 5.6%-11.5%, respectively, over a concentration range of 10 ng/ml to 1000 ng/ml. Overall mean accuracy was 5.2% over this range.

Pharmacokinetic and pharmacodynamic analyses Initially a three-compartment model was fitted to individual DMP 840 plasma concentrations by the method of weighted least squares regression using the program ADAPT II [9, 10], Modeling attempts by this method were unsuccessful for six patients due to end of infusion concentrations that were 30%-75% lower than anticipated and/or incomplete sampling during the infusion (four patients), or post infusion concentrations that were higher than anticipated (two patients). Data from the seven patients that initial modeling attempts were

Results From July, 1994 until February, 1996, 14 patients were enrolled in this study. The median age was 62 years (range 39-83). All patients had a good performance status (ECOG 0 or 1), nine had colorectal cancer and all had previously received chemotherapy, eight were extensively pretreated. The median number of courses that were administered was 2 (range 1-7). Dose escalations and dose reductions were performed in four patients (two each). One course of therapy was incompletely evaluable due to incomplete data collection. Hematologic and non-hematologic toxicities Hematologic toxicity as a function of DMP 840 dose is illustrated in Table 1. Myelosuppression was dose-limiting in both minimally and extensively pretreated patients treated at the 50 and 60 mg/m2 dose levels. Dose-limiting thrombocytopenia, was observed in one patient treated with DMP 840 60 mg/m2. An additional patient developed prolonged, neutropenia resulting in treatment delays with subsequent courses of therapy. Further accrual was therefore continued at the 50 mg/m2 dose level. However, at this dose level, two of five patients, developed dose-limiting grade 4 neutropenia. Mucositis was the predominant non-hematologic toxicity observed in this study. Dose-limiting grade 3 mucositis associated with grade 2 diarrhea was observed in one offivepatients treated with DMP 840 50 mg/m2. Mucositis was very profound in that deep layers of the ventral tongue were involved and the lesions were painful. All DLTs were observed during the first course of treatment.

103 Table 2. DMP 840 pharmacokinetic parameters. Dose (mg/m2)

20 40 50 60

No of pts

C m « (ng/ml)

Vc (1/m2)

Vss (1/m2)

VT (1/m2)

t,, 2 , (mm)

ti/2/s (hours)

t,,2T (hours)

Cl, (1/hour/m2)

AUC (ug/ ml/hour)

3 3 5 2

64 (60-88) 103(86-137) 126(98-175) 140(138-143)

3.5 (0.82-5.7) 4.4 (2.4-7.6) 6.6(3.5-17) 7.0 (6.3-7.8)

461 (66-531) 72(21-113) 194(83^)68) 233(56-410)

735 (529-850) 365 (36
4.5(2.9-10) 7.9 (4.2-7.9) 8.9 (4.8-19) 9.2 (8.7-9.6)

5.1 (4.2-6.4) 0.87(0.43-1.1) 3.9 (1.0-4.3) 3.3 (0.98-5.6)

76 (39-86) 28 (28-32) 39 (37-57) 36 (25-47)

7.8 (5.9-9.4) 9.1 (7.9-11) 9.6(7.3-18) 11 (11-12)

2.6(2.1-3.4) 4.4(3.8-5.1) 5.2 (2.8-6.9) 5.4(5.1-5.6)

6.3 6.1 3.9

113 233 199

529 637 307

7.9 8.2 4.1

3.9 3.1 2 1

39 45 19

9.4 10 3.1

Median Mean SD

Parameter*

a Values are median (ranges). Abrreviations: Cmax - maximum plasma concentration; Vc - volume of the central compartment; Vss - steady-state volume of distribution; Vr apparent volume of distribution; ti/2:,, ti/2p, ti/2y ~~ alpha, beta, and gamma half-lives; Cls - systemic clearance; AUC - area-under the concentration-time curve.

Hematologic DLTs were not observed in patients treated at the 40 mg/m2 dose level. Grade 2 mucositis was observed in 3 of 10 courses at the 40 mg/m2 dose level, and one of seven courses at the 60 mg/m2 dose level. Nausea and vomiting were reported in 10 of 34 courses and were generally of grade 1 severity.

anti-tumor activity in patients with pretreated solid tumor malignancies [e.g., 11, 12] argues against performing broad phase II evaluations of DMP 840 on this more cumbersome schedule. Acknowledgements

Pharmacokinetic andpharmacodynamic analyses Thirteen patients were evaluable for pharmacokinetic and pharmacodynamic analysis. DMP 840 pharmacokinetic parameters are displayed in Table 2. DMP 840 had a prolonged terminal half-life (median 39 hours, range 25-86). Linear correlations were observed between DMP 840 dose and both AUC (r = 0.66, P 0.014) and Cmax (r = 0.75, P - 0.003), within the narrow dose range studied. Systemic plasma clearance was independent of dose (P > 0.1, Kruskal-Wallis test). Significantly higher mean values for parameters of systemic exposure were observed in patients experiencing DLTs (P < 0.01, Wilcoxon Rank Sum test), including AUC (5.7 vs. 3.5 ug/ml/h), Cmax (147 vs. 92 ng/ml) and the times plasma levels exceeded 100 ng/ml (18 vs. 2.4 hours). Conclusions Myelosuppresion and stomatitis were DLTs in the present study. Initial dose escalation of DMP 840 to doses of 40 mg/m2 was well tolerated, however subsequent escalations to doses of 60 mg/m2 and 50 mg/m2 were limited by the development of DLTs in two of four, and three of five patients, respectively, in both extensively and minimally pretreated patients. Pharmacodynamic analysis demonstrated that these events were related to indices of drug exposure. While the anti-tumor activity of DMP 840 has been reported to be greatest at drug concentrations of 100 ng/ml or more [5], such levels were only consistently achieved in patients experiencing DLT. The recommended dose for further evaluations using a 24hour schedule of administration is 40 mg/m2 administered every three weeks. However the lack of significant

Financial support for this study was received from the DuPont Merck Pharmaceutical Company. The generous assistance of M. Duer and B. Hoker with data collection, of V. Peterman with plasma sample analysis, and of H. Stanfield with the preparation of this manuscript is gratefully acknowledged. We would also like to express our gratitude to the medical and nursing staffs at the Johns Hopkins Oncology Center who provided care and support for the patients on this study.

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