A phase I, single center, open-label design was used to assess the safety, pharmacokinetic characteristics and efficacy of 2ME2. This study was conducted at the University of Wisconsin Paul P. Carbone Comprehensive Cancer Center after institutional review board approval. Patients ≥ 18 years old, with biopsy‐proven disease, a life expectancy ≥ 3 months, Karnofsky performance status > 80%; and unresectable or metastatic solid malignancy were eligible. Patients were required to have either progressed on a previous therapy or to lack effective treatment options. Inclusion criteria included at least one measurable lesion as defined by the Response Evaluation Criteria in Solid Tumors (RECIST)15
or, in the case of patients with prostate cancer, a rising serum level of prostate specific antigen (PSA).
Exclusion criteria excluded hematopoietic (Hgb < 10 g/dL, platelets < 75,000/mm3), hepatic (AST or ALT > 2.5 times the upper limit of normal [ULN]) or renal (Cr > 1.5 times ULN) dysfunction. Patients were also excluded for current active brain metastases, use of other anticancer agents, radiotherapy or surgery within the previous four weeks or baseline sensory neuropathy ≥ Grade 2 per the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) Version 3.0. All patients provided written informed consent prior to enrollment.
This study was conducted in two parts. The study initially called for patients to receive drug every 6 hours (Part A). The protocol was later amended to obtain further MTD data using an 8-hour dosing schedule (Part B). The rationale for exploring the every 8-hour dosing schedule was ease of administration and the potential for improved patient convenience. When the study drug was administered every 6 hours, it was noted to interfere with patient sleep. For example, if an evening dose was taken at 10 pm, patients had to awaken at 4 am for the next dose.
For Part A, cohorts A1 (initial accrual level), A2, A3, and A4 corresponded to 1000, 2000, 4000 and 6000 mg/d of 2ME2 NCD. This total daily dose was to be given in equal divisions every 6 hours. Each cohort consisted of three patients. Advancement to the next dose occurred when three patients in the previous cohort completed the 28-day treatment period and 7-day observation period with no evidence of DLT. If none of the three patients in a cohort experienced a DLT, three patients were enrolled in the next higher cohort. Three additional patients were added to a cohort if one of three patients experienced a DLT. If two of three patients experienced a DLT, the MTD was exceeded and additional patients would be enrolled at the next lower dose level.
For Part B, cohorts B1 (initial accrual level), B2, and B3 corresponded to 3000, 3750 and 4500 mg/d of 2ME2 NCD. This total daily dose was to be given in equal divisions every 8 hours. The initial cohort was to consist of four patients. Dose cohorts were to be expanded to include an additional two patients in the event of DLT or to replace patients who discontinued early for reasons other than DLT.
DLT was defined as Grade 3 or greater nonhematological, or Grade 4 hematological, treatment-related toxicity, not returning to baseline within two weeks of onset, or an event that made continued treatment unsafe in the opinion of the investigator. For practical purposes, given that 2ME2 NCD is an oral medication dosed continuously, the investigators did not emphasize the 2-week criteria for duration of DLT. Toxicity was graded according to according to CTCAE Version 3.0. Patients not completing the initial 28-day treatment period for reasons other than DLT were deemed unevaluable for toxicity and were replaced.
Treatment Plan and Patient Follow Up
2ME2 NCD was provided by the study sponsor, EntreMed, Inc. (Rockville, MD). Drug was supplied as 50 or 100 mg/mL dispersion in 8-ounce bottles. Patients received the study drug in four (Part A) or three (Part B) divided daily doses continually throughout a 28-day cycle. Patients who completed the initial 35‐day treatment cycle (a 28-day treatment period followed by a 7-day period of observation) without evidence of DLT or symptomatic disease progression were eligible for additional cycles. Patients were assessed on day 1, 2, 8, 15, and 28 for the first 4 weeks and then on day 1 of each subsequent cycle with clinical exam, chemistries and complete blood counts. Patients enrolled in Part B also had an 8‐day initial treatment period to evaluate the pharmacokinetics (PK) of 2ME2 in the fed versus fasting state. On Day –7, patients received a single oral dose of 2ME2 NCD with food. On Day 0, patients received a single oral dose of 2ME2 NCD after fasting overnight. Patients who discontinued study drug were followed for 30 days subsequently, or until the resolution of any toxicity.
Development of a DLT that did not resolve within 14 days mandated that patients discontinue 2ME2 NCD. If the toxicity resolved in 14 days, the patient resumed therapy at the next lower dose level, or with a 50% dose reduction. Treatment otherwise continued until withdrawal of consent or progressive disease.
Pharmacokinetic parameters of 2ME2 and a principal metabolite 2-methoxyesterone (2ME1) were assessed during cycle 1. For Part A patients, blood samples were drawn on Day 1, at baseline, at 30 and 60 minutes, 2, 4, 6, 12, 18, 18.5, 19, 20, 22 and 24 hours after the first dose of 2ME2. Blood samples were also drawn immediately before the first dose on Days 15, 22, and 28. In addition, blood samples were drawn at 30 and 60 minutes, 2, 4, and 6 hours after the first dose on Day 28. For Part B patients, blood samples for pharmacokinetic analysis were drawn on Day -7 (fed) and Day 0 (fasted), at baseline, at 30 and 60 minutes, and 2, 4, 6, 8, 12, 18, and 24 hours following the initial dose. Blood samples were also drawn immediately before the first dose on Days 15, 22, and 28. In addition, on Day 28, blood samples were drawn for pharmacokinetic analysis at 30 and 60 minutes, and 2, 4, 6, and 8 hours after the last dose of 2ME2 NCD before the observation period. On subsequent cycles for both Part A and B patients, samples were drawn immediately before the first dose on Day 28.
The plasma concentration-time data were analyzed by standard non-compartmental methods using Kinetica®, Version 4.2 (Thermo-Fisher, Philadelphia, PA). Area under the concentration-time curves was calculated using linear trapezoidal method.
Tumor response was assessed using RECIST15
after the first cycle and then every other cycle. Patients with prostate cancer and nonmeasurable disease were followed with tumor markers (PSA) using PSA consensus criteria.16
Data were summarized in tables listing the mean, standard deviation, minimum, median, maximum, and number of patients for continuous data, or in tables listing count and percentage for categorical data, where appropriate. Statistical analyses were performed and data appendices were created by using the SAS® system, Version 9.1.3.