A phase I and pharmacokinetic study of oral perifosine with different loading schedules in patients with refractory neoplasms.

PURPOSE: To determine the maximum tolerated dose (MTD) of perifosine (NSC 639966), an alkylphospholipid modulator of signal transduction, using different oral loading and maintenance regimens in an effort to avoid gastrointestinal toxicity while seeking maximal sustained plasma concentrations. METHODS: Thirty-one patients with advanced neoplasms were treated with monthly cycles of perifosine loading doses of 300, 600, 900, 1,200 and 1,500 mg (dose levels 1 through 5, respectively) on days 1-2 depending on the actual dose of the initial cycle. For subsequent cycles, perifosine loading doses were reduced to 100, 200, 300, 400 and 1,000 mg at the respective corresponding dose levels. Daily perifosine "maintenance" doses of 50, 100, 150, 200 and 250 mg for levels 1 through 5, respectively, commenced on days 2 or 3 and continued for a total of 21 days. No treatment was given for days 22-27. The pharmacokinetics of perifosine with these schedules was characterized. RESULTS: Dose-limiting diarrhea developed at or above dose level 4. The MTD and recommended phase II dose was dose level 3B, with a loading dose of 900 mg on day 1 divided into two doses of 450 mg administered 6 h apart and a maintenance dose of 150 mg on day 2 through 21. On subsequent cycles, the loading dose was reduced to 300 mg. Non-gastrointestinal toxicities included three episodes of gout or gout-like syndromes observed at doses above the MTD. The median peak plasma concentration of perifosine achieved at the MTD was approximately 8.3 µg/mL. Four patients had stable disease ranging from 167 to 735 days. CONCLUSIONS: Perifosine given according to a loading and maintenance schedule can safely sustain concentrations of drug, approaching concentrations achieved in preclinical models with evidence of anti-tumor effect.

A randomized phase 2 trial comparing 3-hour versus 96-hour infusion schedules of paclitaxel for the treatment of metastatic breast cancer.

BACKGROUND: This study was performed to compare efficacy and toxicity profiles of paclitaxel using 3-hour versus 96-hour infusion schedules. METHODS: Patients with metastatic breast cancer (MBC) were randomly assigned to receive paclitaxel starting at a dose of 250 mg/m(2) intravenously (iv) over 3 hours every 21 days or paclitaxel starting at a dose of 140 mg/m(2) iv over 96 hours every 21 days. Stratification variables included number of prior chemotherapy regimens and previous response to anthracyclines. Response was assessed every 2 cycles using bidimensional measurements. Patients were allowed to cross over at disease progression or therapy intolerance. RESULTS: A total of 214 patients received therapy (107 patients per arm). Response rates were similar: 23.4% in the 3-hour arm and 29.9% in the 96-hour arm (P = .28). The median duration of response (8.9 months vs 5.7 months; P = .75) and progression-free survival (5.0 months vs 3.8 months; P = .17) slightly favored the 96-hour arm. Overall survival was slightly longer in the 3-hour arm (14.2 months vs 12.7 months; P = .57). One patient who crossed over to the 96-hour arm (N = 18) developed a partial response; no response was noted with crossover to the 3-hour arm (N = 10). Myalgia/arthralgia and neuropathy were more frequent in the 3-hour arm, whereas mucositis, neutropenic fever/infection, and diarrhea were more common in the 96-hour arm. CONCLUSIONS: Paclitaxel given by 3-hour or 96-hour infusion was active in MBC. The 96-hour paclitaxel regimen did not significantly improve response or time to disease progression, was more cumbersome to administer, and was associated with greater myelosuppression (but less neuropathy and myalgia) compared with the 3-hour schedule.

Clinical trial endpoints in ovarian cancer: report of an FDA/ASCO/AACR Public Workshop.

OBJECTIVE: The unique characteristics of cancer, particularly issues involving the use of surrogate endpoints in clinical trials, present special challenges in the development of cancer drugs. In response, the U.S. Food and Drug Administration (FDA) has partnered with the American Society of Clinical Oncology, the American Association for Cancer Research, and the American Society of Hematology to conduct public workshops evaluating potential endpoints for drug approvals for the most common tumor types. METHODS: A workshop evaluating potential endpoints in ovarian cancer drug research was held in Bethesda, Maryland, in April 2006. Invited experts presented research findings and discussed endpoints in trials of drugs for treatment of Stage III and IV ovarian cancer. RESULTS: The panel responded to specific questions from FDA, discussing use of progression-free survival as a surrogate for overall survival and use of CA-125 levels as an indicator of response. Panel members also addressed endpoints in first-line therapy, second-line and subsequent therapy, and maintenance therapy. CONCLUSION: Expert commentary provided by panel members will inform FDA's draft guidance on clinical endpoints for cancer drug approvals and will be discussed at meetings of the FDA's Oncologic Drugs Advisory Committee. FDA intends to develop a set of principles that can be used to define efficacy standards for drugs used to treat ovarian and other cancers.

Clinical pharmacology of flavopiridol following a 72-hour continuous infusion.

BACKGROUND: Flavopiridol, a novel flavone derivative, inhibits cyclin-dependent kinase-1. We initiated a Phase I trial in patients with refractory solid tumors to determine the maximum tolerated dose and characterize the adverse effect profile. OBJECTIVE: To characterize the clinical pharmacology of flavopiridol. METHODS: Serial plasma samples were collected and analyzed by HPLC using electrochemical detection. The pharmacokinetics were analyzed by noncompartmental analysis. Enterohepatic recirculation was studied by analyzing fecal samples, with an attempt to correlate cholecystokinin and post-infusional peak concentrations. The plasma protein binding was studied using equilibrium dialysis. RESULTS: Seventy-six patients were treated with flavopiridol at 13 dose levels for a total of 504 cycles of treatment. The average steady-state concentration was 26.5 and 253 nM at 4 and 122.5 mg/m2, respectively. The clearance ranged from 49.9 to 2943 mL/min, with nonlinearity at doses >50 mg/m2/d. A post-infusional increase in plasma flavopiridol concentrations was noted in a subset of patients and generally occurred between 3 and 24 hours after the end of infusion. Flavopiridol was found in fecal matter, suggesting enterohepatic recirculation. There was nonsaturable plasma protein binding of flavopiridol (fu = 6%). CONCLUSIONS: The dose-limiting toxicity for the Phase I trial of flavopiridol was secretory diarrhea. We failed to identify a clear relationship between dose or concentration and diarrhea. At 50 and 78 mg/m2/d, the mean steady-state plasma concentrations were 278 and 390 nM. These concentrations were well above those noted for in vitro antiproliferative activity. Nonlinear elimination was observed at doses above 50 mg/m2/d, and postinfusional peaks appear to be related to enterohepatic recirculation.

Phase III trial of paclitaxel at two dose levels, the higher dose accompanied by filgrastim at two dose levels in platinum-pretreated epithelial ovarian cancer: an intergroup study.

PURPOSE: To determine if increasing the dose of paclitaxel increases the probability of clinical response, progression-free survival, or overall survival in women who have persistent or recurrent ovarian cancer, and whether doubling the dose of prophylactic filgrastim accompanying the higher paclitaxel dose decreases the frequency of neutropenic fever. PATIENTS AND METHODS: Consenting patients with persistent, recurrent, or progressing ovarian cancer, despite first-line platinum therapy (but no prior taxane), were randomly assigned to paclitaxel 135 mg/m2, 175 mg/m2, or 250 mg/m2 over 24 hours every 3 weeks. Patients receiving paclitaxel 250 mg/m2 were also randomly assigned to 5 or 10 microg/kg of filgrastim per day subcutaneously. RESULTS: Accession to the paclitaxel 135-mg/m2 arm was closed early. Among the 271 patients on the other regimens with measurable disease, partial and complete response on paclitaxel 250 mg/m2 (36%) was significantly higher than on 175 mg/m2 (27%, P =.027). This difference was more evident among patients who never responded to prior platinum. However, progression-free and overall survival results were similar. The median durations of overall survival were 13.1 and 12.3 months for paclitaxel 175 mg/m2 and 250 mg/m2, respectively. Thrombocytopenia, neuropathy, and myalgia were greater with paclitaxel 250 mg/m2 (P <.05). The incidence of neutropenic fever after the first cycle of paclitaxel 250 mg/m2 was 19% and 18% on the 5-microg/kg and 10-microg/kg filgrastim dose, respectively (22% for paclitaxel 175 mg/m2 without filgrastim). CONCLUSION: Paclitaxel exhibits a dose effect with regard to response rate, but there is more toxicity and no survival benefit to justify paclitaxel 250 mg/m2 plus filgrastim. Doubling the filgrastim dose from 5 to 10 microg/kg did not reduce the probability of neutropenic fever after high-dose paclitaxel.

Phase I clinical and pharmacokinetic study of flavopiridol administered as a daily 1-hour infusion in patients with advanced neoplasms.

PURPOSE: To define the maximum-tolerated dose (MTD), dose-limiting toxicity, and pharmacokinetics of the cyclin-dependent kinase inhibitor flavopiridol administered as a daily 1-hour infusion every 3 weeks. PATIENTS AND METHODS: Fifty-five patients with advanced neoplasms were treated with flavopiridol at doses of 12, 17, 24, 30, 37.5, and 52.5 mg/m(2)/d for 5 days; doses of 50 and 62.5 mg/m(2)/d for 3 days; and doses of 62.5 and 78 mg/m(2)/d for 1 day. Plasma sampling was performed to characterize the pharmacokinetics of flavopiridol with these schedules. RESULTS: Dose-limiting neutropenia developed at doses >/= 52.5 mg/m(2)/d. Nonhematologic toxicities included nausea, vomiting, diarrhea, hypotension, and a proinflammatory syndrome characterized by anorexia, fatigue, fever, and tumor pain. The median peak concentrations of flavopiridol achieved at the MTDs on the 5-day, 3-day, and 1-day schedule were 1.7 micro mol/L (range, 1.3 to 4.2 micro mol/L), 3.2 micro mol/L (range, 1.7 to 4.8 micro mol/L), and 3.9 micro mol/L (1.8 to 5.1 micro mol/L), respectively. Twelve patients had stable disease for >/= 3 months, with a median duration of 6 months (range, 3 to 11 months). CONCLUSION: The recommended phase II doses of flavopiridol as a 1-hour infusion are 37.5 mg/m(2)/d for 5 days, 50 mg/m(2)/d for 3 days, and 62.5 mg/m(2)/d for 1 day. Flavopiridol as a daily 1-hour infusion can be safely administered and can achieve concentrations in the micromolar range, sufficient to inhibit cyclin-dependent kinases in preclinical models. Further studies to determine the optimal schedule of flavopiridol as a single agent and in combination with chemotherapeutic agents are underway.