Kendra D. Tutsch

Phase I Pharmacokinetic and Pharmacodynamic Study of Recombinant Human Endostatin in Patients With Advanced Solid Tumors

PURPOSE Endostatin is the first endogenous angiogenesis inhibitor to enter clinical trials. Laboratory investigations with endostatin have indicated broad antitumor activity coupled with remarkably low toxicity. A phase I trial of recombinant human endostatin was designed to evaluate toxicity and explore biologic effectiveness in patients with refractory solid tumors. PATIENTS AND METHODS Endostatin was administered as a 1-hour intravenous infusion given daily for a 28-day cycle. A starting dose of 30 mg/m2 was explored with subsequent dose escalations of 60, 100, 150, 225, and 300 mg/m2. Assessment of serum pharmacokinetics was performed on all 21 patients. Western blot assay and mass spectroscopy were employed to evaluate endostatin metabolism. Circulating levels of endogenous proangiogenic growth factors were examined. Tumor and tumor blood supply were imaged by dynamic computed tomography (CT), magnetic resonance imaging, ultrasound, and positron emission tomography. RESULTS Endostatin given on this schedule was essentially free of significant drug-related toxicity. Two transient episodes of grade 1 rash were observed. No clinical responses were observed. Endostatin pharmacokinetics were linear with dose, and serum concentrations were achieved that are associated with antitumor activity in preclinical models. No aggregate effect on circulating proangiogenic growth factors were seen, although several patients exhibited persistent declines in vascular endothelial growth factor levels while enrolled in the study. A few patients demonstrated changes in their dynamic CT scans suggestive of a decline in microvessel density, although overall, no consistent effect of endostatin on tumor vasculature was seen. CONCLUSION Endostatin given daily as a 1-hour intravenous infusion was well tolerated without dose-limiting toxicity at doses up to 300 mg/m2.

A Phase I Trial of Perifosine (NSC 639966) on a Loading Dose/Maintenance Dose Schedule in Patients with Advanced Cancer

Perifosine (NSC 639966) is a synthetic, substituted heterocyclic alkylphosphocholine that acts primarily at the cell membrane targeting signal transduction pathways. Early clinical trials were limited because of dose-limiting gastrointestinal toxicity, and parenteral dosing of this class of agents is not possible because of their hemolytic properties; therefore, related compounds with an improved therapeutic index were developed. Toxicity was minimized and efficacy improved by using a loading dose/maintenance dose schedule, and therefore, this schedule was carried into clinical trials. This phase I trial enrolled 42 patients with incurable solid malignancies. The starting doses were 100 mg p.o. × four doses (every 6 hours) load followed by a 50 mg p.o. once daily maintenance dose with escalation of either component in successive dose levels. No treatment related deaths occurred. The maximum-tolerated dose was determined to be 150 mg p.o. × four doses load and 100 mg p.o. once daily maintenance. Dose-limiting toxicities such as nausea, diarrhea, dehydration, and fatigue were seen early during the loading phase and were surmountable with the use of prophylactic 5-HT3 receptor antagonists, dexamethasone, and loperamide. Toxicities during the chronic phase were difficult to manage and, given that pharmacokinetic data showed biologically active serum concentrations (based on preclinical data), raised the question of less frequent maintenance dosing. Pharmacokinetic data confirmed the maintenance of stable drug levels with chronic dosing and the long half-life. One partial response was seen, as were multiple patients with stable disease beyond course 2. These results suggest perifosine activity in sarcoma and perhaps renal cell carcinoma (stable disease in two patients who continued for 6 and 14 courses), thus justifying additional investigation of this agent in a phase II sarcoma trial.

Phase I clinical trial of intravenous L-buthionine sulfoximine and melphalan: An attempt at modulation of glutathione

PURPOSE A phase I dose-escalation trial of intravenous (IV) L-buthionine-SR-sulfoximine (BSO) with melphalan (L-PAM) was performed to determine the toxicity and biologic activity of BSO, administered as a short infusion every 12 hours, and the combination of BSO plus L-PAM. PATIENTS AND METHODS Twenty-eight patients with refractory malignancies received 30-minute infusions of BSO every 12 hours for 6 to 10 doses in week 1 followed in week 2 by either IV L-PAM (15 mg/m2) alone or BSO as in week 1 with L-PAM. Patients received the combination in week 5 (course no. 2) if they received L-PAM alone during week 2 and vice versa. BSO doses ranged from 1.5 g/m2 to 13.104 g/m2. RESULTS The only toxicity observed with BSO infusions was occasional nausea/vomiting. Evaluation of 23 paired courses (L-PAM plus BSO v L-PAM) showed significantly (P < .001) greater leukopenia and thrombocytopenia with L-PAM plus BSO. No other significant toxicity was noted. Measurement of intracellular glutathione (GSH) levels in peripheral mononuclear cells (PBLs) of all patients receiving BSO showed a consistent, non-dose-dependent, linear decrease in GSH with repeated BSO doses. Maximal GSH depletion (40% of baseline values, absolute values 200 to 250 ng/10(6) PBLs) was noted after the sixth BSO dose; extended BSO dosing schedules beyond six total BSO doses did not further deplete GSH. Evaluation of gamma-glutamylcysteine synthetase (GCS) activity showed marked inhibition near the end of each infusion with near complete recovery of GCS activity before the next BSO dose. The pattern of GCS inhibition mirrored the plasma BSO concentrations with peak values (level 6, 4 to 8 mmol/L L,R+L,S BSO) observed at the end of the infusion with a rapid decrease in plasma concentrations with an estimated half-life (t1/2) of less than 2 hours. Differential elimination of the R+S stereoisomers was observed. Analysis of L-PAM pharmacokinetics showed marked interpatient variability and a significant decrease in total-body clearance (P = .01) and volume of distribution (P = .03) in courses with L-PAM plus BSO as compared with L-PAM alone. CONCLUSION This study shows that BSO alone and in combination with L-PAM can be safely given to patients, but that a schedule of short infusions every 12 hours does not result in GSH depletion less than 30% of baseline values.

Phase I trial of 3-hour infusion of paclitaxel with or without granulocyte colony-stimulating factor in patients with advanced cancer.

PURPOSE We conducted a phase I trial of a 3-hour infusion of Taxol (paclitaxel; Bristol-Myers Squibb Co, Princeton, NJ) to identify the maximum-tolerated dose of Taxol as a 3-hour infusion with and without granulocyte colony-stimulating factor (G-CSF) support. MATERIALS AND METHODS Thirty-five patients with advanced, untreatable malignancies were treated with a 3-hour infusion of Taxol once every 3 weeks. Groups of three patients were entered at escalating dose levels of Taxol in a traditional phase I design in each of two parallel arms: arm A, without G-CSF, and arm B, with G-CSF. Patients assigned to the G-CSF arm received G-CSF 5 micrograms/kg/d subcutaneously starting on day 2 for 9 to 14 days. All patients were pretreated with dexamethasone, diphenhydramine, and ranitidine, and were monitored continuously for cardiac arrhythmias during the first treatment. RESULTS Dose-limiting myelosuppression with Taxol without G-CSF was observed at the 250-mg/m2 dose level. The dose-limiting toxicity for Taxol with G-CSF was peripheral neuropathy at the 300-mg/m2 dose level. One of 35 patients (2.8%) had a grade 3 anaphylactic reaction at 250 mg/m2. No clinically significant cardiac arrhythmias were documented. Twenty-seven of 111 courses (24%) were associated with grade 3 arthralgias or myalgias requiring narcotics for pain control. Taxol plasma concentrations declined in a triexponential fashion, with a final elimination half-life of 10 to 12 hours. The peak Taxol plasma concentrations and total area under the curve (AUC) increased with increasing doses of Taxol, although this increase appeared to be somewhat nonlinear. CONCLUSION The maximum dose of Taxol recommended for phase II and III studies, when administered as a 3-hour infusion alone and with G-CSF support, is 210 mg/m2 and 250 mg/m2, respectively. No increased incidence of hypersensitivity reactions or other side effects were observed, with the possible exception of arthralgias and myalgias. If ongoing trials demonstrate that a 3-hour infusion is as efficacious as a 24-hour infusion, we conclude that with proper monitoring and premedication, high-dose Taxol can be safely administered in the outpatient setting.

Phase I clinical trial of melphalan and 41.8°C whole-body hyperthermia in cancer patients

PURPOSE To evaluate the biologic interactions and toxicities of melphalan (L-PAM) combined with 41.8 degrees C whole-body hyperthermia (WBH) for 60 minutes. PATIENTS AND METHODS Sixteen patients with refractory cancer were treated (May 1992 to May 1995) with WBH alone during week 1) thereafter patients were randomized to receive either L-PAM alone on week 2 and L-PAM plus WBH on week 5, or the reverse sequence. Patients who demonstrated clinical improvement received WBH plus L-PAM monthly. Dose levels of L-PAM were 10 mg/m2 (n = 3), 15 mg/m2 (n = 3), 17.5 mg/m2 (n = 6), and 20 mg/m2 (n = 4). L-PAM was administered at target temperature; WBH was administered with an Aquatherm radiant-heat device (patent pending; Cancer Research Institute, New York, NY). RESULTS Comparisons of mean WBC count and platelet nadirs for L-PAM alone and L-PAM plus WBH demonstrated that the addition of WBH resulted in nadir counts that were, on average, 25% lower. There were no instances of febrile neutropenia or bleeding. Toxicities allowed for escalation of L-PAM to 20 mg/m2; all four patients at this level experienced grade 4 myelosuppression. No significant myelosuppression was observed at 10 and 15 mg/m2. Grade 3 myelosuppression was observed in two of six patients at 17.5 mg/m2. Responses included complete remission (CR) of pancreatic cancer (10 mg/m2), partial remission (PR) of malignant melanoma in two patients (20 mg/m2), and transient clinical and/or serologic improvement in five patients. The pharmacokinetics of L-PAM were not altered by WBH. Observed cytokine induction by WBH is also discussed in detail. CONCLUSION We conclude that L-PAM with 41.8 degrees C WBH is well tolerated. Clinical results are consistent with preclinical predictions and provide a foundation for second-generation trials now in progress.

Pharmacokinetic and pharmacodynamic analysis of fluorouracil during 72-hour continuous infusion with and without dipyridamole.

During a phase I trial of 3-day simultaneous continuous intravenous infusions of varying doses of fluorouracil (5FUra) and 7.7 mg/kg/d of dipyridamole, we examined the relationships between 5FUra dose and steady-state plasma concentration (Css) and the percentage reduction in WBCs, as well as the percentage frequency of stomatitis. The 5FUra was administered at doses ranging from 185 mg/m2/d times three to 3,600 mg/m2/d times three. In 42 patients, 86 cycles of 5FUra plus dipyridamole and 28 cycles of 5FUra alone were analyzed. The Css of 5FUra varied even within the same dose level. When patients receiving the same 5FUra dose were considered, the interpatient coefficient of variation of 5FUra Css in cycles of 5FUra plus dipyridamole was 23% +/- 4.2%. For courses of 5FUra alone, the coefficient of variation of 5FUra was 15.6% +/- 6.5%. When the occurrence of any degree of stomatitis was related to the Css 5FUra, with patients grouped in cohorts of 2-mumol/L increments, the following equations accurately described the frequency of stomatitis: for 5FUra plus dipyridamole, percentage frequency of stomatitis = 100(1-e-0.114Css), r2 = 0.88; for 5FUra alone, percentage frequency stomatitis = 100(1-e0.122Css), r2 = 0.80. When 5FUra dose was substituted for Css, these relationships were as follows: percentage frequency of stomatitis = 100(1-e-0.00031 [dose]), r2 = 0.85; and percentage frequency of stomatitis = 100(1-e-0.00051 [dose]), r2 = 0.80. When the relationship between the percentage reduction in WBC and Css 5FUra was examined, statistically significant relationships were also apparent: for 5FUra plus dipyridamole, percentage reduction in WBC = 100(1-e-0.085Css), r2 = 0.46; for 5FUra alone, percentage reduction in WBC = 100(1-e-0.060Css), r2 = 0.61. When 5FUra dose was substituted for Css, these relatinships were as follows: percentage reduction in WBC = 100(1-e-0.00023 [dose]), r2 = 0.40; percentage reduction in WBC = 100(1-e-0.00024 [dose]), r2 = 0.65. The relationship between either Css 5FUra or dose 5FUra and either stomatitis or myelosuppression were also well described by the modified Hill equation (J Theor Biol 20:171-201, 1968). These analyses indicate that it should be possible to develop therapeutic regimens wherein 5FUra is administered to achieve a targeted Css determined by the risk and severity of toxicity deemed acceptable.

Phase I clinical trial and pharmacokinetics of carboplatin (NSC 241240) by single monthly 30-minute infusion

Carboplatin (diammine[1,1‐cyclobutanedicarboxylate(2‐)‐O,ó]platinum) is a second generation platinum coordination complex. It has a spectrum of activity that is similar to that of cisplatin and is less nephrotoxic and emetogenic in experimental animals. Fifty‐two 30‐minute infusions of carboplatin were given to 20 evaluable patients with a variety of solid tumors. Maximum tolerated dose was 440 mg/m2. Thrombocytopenia (<100,000/mm3) occurred in six of seven patients; two patients experienced a leukocyte count less than 2000/mm3. Platelet and leukocyte count nadirs occurred on day 21. No nephrotoxicity was seen. Blood urea nitrogen, serum creatine levels, and creatinine clearances remained normal, and no consistent elevation of urinary β2‐microglobulin, leucine aminopeptidase, or N‐acetyl‐β‐glucosaminidase occurred. Nausea and vomiting were mild to moderate. A single patient developed mild peripheral neuropathy. No auditory toxicity was noted. The recommended dose for Phase II studies is 400 mg/m2 every 28 days for good risk patients; heavily pretreated patients should receive 320 mg/m2.

A Phase I and Pharmacologic Trial of Two Schedules of the Proteasome Inhibitor, PS-341 (Bortezomib, Velcade), in Patients with Advanced Cancer

Purpose: To define the toxicities, pharmacodynamics, and clinical activity of the proteasome inhibitor, PS-341 (bortezomib), in patients with advanced malignancies. Patients and Methods: Twenty-eight patients (14 male and 14 female) received PS-341 twice weekly for 4 of 6 weeks (schedule I). Because toxicity necessitated dose omissions on this schedule, 16 additional patients (12 male and 4 female) received PS-341 twice weekly for 2 of every 3 weeks (schedule II). A total of 73 courses of treatment was given (median, 2; range, 1-4). Inhibition of 20S proteasome activity in peripheral blood mononuclear cells (PBMC) and accumulation of proteasome-targeted polypeptides in tumor tissue were evaluated as pharmacodynamic markers of PS-341 activity. Results: The most common toxicity was thrombocytopenia, which was dose limiting at 1.7 mg/m2 (schedule I) and 1.6 mg/m2 (schedule II), respectively. Sensory neuropathy was dose-limiting in a patient in schedule I. Grade ≥3 toxicities for schedule I were constipation, fatigue, myalgia, and sensory neuropathy. Grade ≥3 toxicities for schedule II were dehydration resulting from diarrhea, nausea and vomiting, fatigue, hypoglycemia, and hypotension. The maximum tolerated dose was 1.5 mg/m2 for both schedules. Reversible dose-dependent decreases in 20S proteasome activity in PBMCs were observed, with 36% inhibition at 0.5 mg/m2, 52% at 0.9 mg/m2, and 75% at 1.25 mg/m2. Accumulation of proteasome-targeted polypeptides was detected in tumor samples after treatment with PS-341. A patient with multiple myeloma had a partial response. Conclusion: PS-341 given 1.5 mg/m2 twice weekly for 2 of every 3 weeks is well tolerated and should be further studied.

Phase I clinical and pharmacokinetic study of oral carboxyamidotriazole, a signal transduction inhibitor.

PURPOSE We conducted a phase I trial of carboxyamidotriazole (CAI, NSC 609974), designed to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetic characteristics of CAI gelatin capsule (gelcap) formulation administered daily as a single oral dose. PATIENTS AND METHODS Twenty-nine patients with advanced malignancy who met standard eligibility criteria were treated with once-daily CAI given in cycles of 28 days. Pharmacokinetic sampling was performed on days 1 and 29 and trough plasma CAI levels were assessed weekly. RESULTS Patients were entered at dose levels of 50, 75, and 100 mg/m2. All three patients at the 100-mg/m2 level experienced dose-limiting neurocerebellar toxicity. Other neurotoxicities were mild. Gastrointestinal side effects were common, but generally mild, with 23 patients experiencing nausea and/or vomiting of any grade. Fatigue was a frequent complaint, with 19 patients experiencing mild to moderate symptoms. Six patients with nausea and vomiting and five with fatigue experienced relief of symptoms with a change to nocturnal administration of CAI. Peak plasma concentrations (Cp) occurred at 2.4 +/- 1.5 hours after administration of the oral gelcap dose. Patients approached steady-state trough plasma concentrations (Css) by days 8 to 15 and maintained a relatively constant Css throughout the course of treatment. For all patients, the mean variation in weekly CAI Cp was 12.4% +/- 5.3%. CONCLUSION The MTD for the gelcap formulation was 75 mg/m2 with dose-limiting neurocerebellar toxicity (ataxia) seen at 100 mg/m2. Other prominent side effects, including nausea, vomiting, and fatigue, were partially alleviated through altering the administration schedule to nighttime dosing.

Phase II trial of perillyl alcohol (NSC 641066) administered daily in patients with metastatic androgen independent prostate cancer

Objective. We conducted a phase II multicenter trial of perillyl alcohol in patients with advanced hormone refractory prostate cancer (HRPC). The primary endpoint was to evaluate the 6-month progression-free survival given the potential cytostatic nature of the drug. Secondary objectives included assessing acute and chronic toxicities, as well as measuring objective response rates. Methods. Patients with metastatic androgen-independent prostate cancer that failed at least one prior chemotherapeutic or experimental regimen were eligible. Perillyl alcohol was administered orally at 1200 mg/m2/dose four times daily and continued until disease progression or development of unacceptable toxicity. Results. Fifteen patients were eligible. Six patients received less than one cycle (4 weeks) of drug, four of which stopped because of drug intolerance. Only six patients received more than two cycles of therapy and were considered evaluable for response. Main toxicity included grade 1–2 gastrointestinal intolerance (nausea/vomiting in 60% of the patients) and fatigue (47%). One patient developed a grade 4 hypokalemia that was felt likely attributable to the drug. No objective responses were seen. All patients either progressed or withdrew from the study secondary to drug intolerance before the 6-month time period. Conclusion. Perillyl alcohol administered at this dose and formulation did not have any objective clinical activity in this patient population.