A phase 1 clinical trial of sequential pralatrexate followed by a 48-hour infusion of 5-fluorouracil given every other week in adult patients with solid tumors.

BACKGROUND: Pralatrexate (PDX) is an inhibitor of dihydrofolate reductase that was rationally designed to improve cellular uptake and retention of the drug. Preclinical data have shown synergy with the sequential administration of a dihydrofolate reductase inhibitor followed 24 hours later by 5-fluorouracil (5-FU). METHODS: Twenty-seven patients were enrolled at 1 of 5 PDX dose levels from 75 to 185 mg/m(2) on day 1 followed 24 hours later by 5-FU at a dose of 3000 mg/m(2) /48 hours every 2 weeks with folic acid and vitamin B12 supplementation. Baseline blood was collected for pharmacogenetic analysis of polymorphisms of methylenetetrahydrofolate reductase and thymidylate synthase. RESULTS: Mucositis was the most common dose-limiting toxicity. When the worst toxicities across all cycles were considered, grade 3 to 4 neutropenia, anemia, and thrombocytopenia were found to have occurred in 14.8%, 14.8%, and 0% of patients, respectively. Grade 2 to 3 toxicities included mucositis (66.6%), dehydration (33.3%), fatigue (25.9%), and diarrhea (22.2%). Version 3.0 of the National Cancer Institute Common Toxicity Criteria was used to grade toxicities The median progression-free survival (PFS) was 112 days (range, 28-588 days). Seven patients (26%) had a PFS of >180 days (5 patients with colorectal cancer, 1 patient with pancreatic cancer, and 1 patient with non-small cell lung cancer). Polymorphisms in methylenetetrahydrofolate reductase and thymidylate synthase did not correlate with toxicity. CONCLUSIONS: The recommended dose of PDX was 148 mg/m(2) . A subset of heavily pretreated patients had PFS durations of ≥6 months with this regimen.

A phase II study of pralatrexate with vitamin B12 and folic acid supplementation for previously treated recurrent and/or metastatic head and neck squamous cell cancer.

BACKGROUND: Pralatrexate (Fotolyn(TM); Allos Therapeutics Inc.) is an antifolate dihydrofolate reductase (DHFR) inhibitor. We conducted a phase II study of pralatrexate with folic acid and B12 supplementation in patients with recurrent and/or metastatic head and neck squamous cell cancer (R/M HNSCC). PATIENTS AND METHODS: This was a single-arm, Simon optimal two stage phase II study. Patients with R/M HNSCC previously treated with chemotherapy were eligible. The study was initiated with a dosing schedule of pralatrexate 190 mg/m(2) biweekly on a 4-week cycle with vitamin supplementation. Due to toxicity concerns, the dosing was modified to 30 mg/m(2) weekly for 3 weeks in a 4-week cycle with vitamin supplementation. Radiologic imaging was to be obtained about every 2 cycles. RESULTS: Thirteen subjects were enrolled; 12 were treated. Seven of the twelve patients had previously received ≥2 lines of chemotherapy. The most common grade 3 toxicity was mucositis (3 patients). Seven patients did not complete two cycles of therapy due to progression of disease (4), toxicity (1), death (1), and withdrawal of consent (1). Two deaths occurred: one due to disease progression and the other was an unwitnessed event that was possibly related to pralatrexate. No clinical activity was observed. The median overall survival was 3.1 months. The study was closed early due to lack of efficacy. CONCLUSIONS: Pralatrexate does not possess clinical activity against previously treated R/M HNSCC. Evaluation of pralatrexate in other clinical settings of HNSCC management with special considerations for drug toxicity may be warranted.

Preemptive leucovorin administration minimizes pralatrexate toxicity without sacrificing efficacy.

Balancing efficacy and safety of drugs is key for successful cancer therapy, as adverse reactions can prohibit the use of efficacious treatments. Pralatrexate (PDX) is a novel antifolate with a higher affinity for tumor cells than methotrexate, Food and Drug Administration (FDA) approved for use in relapsed and refractory peripheral T-cell lymphoma (PTCL) and transformed mycosis fungoides (T-MF). Patients with T-MF have a higher incidence of adverse events than patients with other lymphomas, necessitating a lower recommended dose of 15 mg/m(2) (vs. 30 mg/m(2) for PTCL). Dose-limiting toxicity (DLT) mucositis occurs in about 25% of patients with T-MF, but milder mucositis is observed in almost all patients with T-MF, frequently leading to therapy discontinuation despite clinical response. Leucovorin rescue is the standard of care for high-dose methotrexate therapy, but has not been studied or recommended for use with PDX. We report our clinical experience using leucovorin with PDX (30 mg/m(2)) with good clinical response and no DLTs. Prophylactic leucovorin deserves further investigation in prospective clinical trials to allow patients with cutaneous lymphomas to receive the full benefit of PDX therapy without intolerable toxicity.

Pralatrexate: treatment of T-cell non-Hodgkin's lymphoma.

Pralatrexate is a folate analogue metabolic inhibitor manufactured by Allos Therapeutics, Inc., a wholly-owned subsidiary of Spectrum Pharmaceuticals, Inc. In both preclinical and clinical studies, pralatrexate demonstrated activity in lymphoma. Pralatrexate was US FDA approved for the treatment of relapsed/refractory peripheral T-cell lymphoma in 2009. Approval was based on data from the PROPEL trial that demonstrated an overall response rate of 29% in a heavily pretreated patient population. The dose and schedule of pralatrexate is 30-mg/m(2) weekly for 6 weeks, given in 7-week cycles. Folate and vitamin B12 supplementation are required to minimize toxicity. The most common toxicities are mucositis, thrombocytopenia, nausea and fatigue.

Efficacy and safety of CH-1504, a metabolically stable antifolate, in patients with active rheumatoid arthritis: results of a phase II multicenter randomized study.

OBJECTIVE: To investigate the potential efficacy, safety, and tolerability of daily use of CH-1504 in patients with active rheumatoid arthritis (RA). US National Institutes of Health database no. NCT00658047. METHODS: In our phase II randomized double-blind double-dummy study, patients naive to methotrexate (MTX; n = 201) and having moderate to severe RA received either CH-1504 (0.25 mg, 0.5 mg, or 1.0 mg once-daily oral doses) or MTX (titrated to 20.0 mg once-weekly oral doses). All received weekly 10-mg folate supplementation. Efficacy and safety were assessed at 2, 4, 8, and 12 weeks, with a treatment-free followup at 16 weeks. Safety and tolerability were assessed. Primary efficacy endpoint was proportion of patients achieving ACR20 response at Week 12. Secondary endpoints included difference from baseline in the 28-joint Disease Activity Score (DAS28) and individual components of the American College of Rheumatology (ACR) composite index. RESULTS: Demographic characteristics were similar in all treatment groups: mean age 54.3 ± 11.4 years, female sex 87%, mean baseline DAS28 6.6 ± 0.9. At Week 12, CH-1504 demonstrated comparable efficacy compared to MTX as measured by ACR20, DAS28, and ACR composite core-set measures, including tender and swollen joints. No dose-response relationship was observed. Adverse events across treatment groups were mild. Liver enzyme levels increased from baseline to Week 16 in the MTX group, with qualitatively lesser increases in the CH-1504 groups. Two patients in the MTX group withdrew because of gastrointestinal-related adverse events. CH-1504 appeared safe and well tolerated at all dose levels. CONCLUSION: CH-1504 has comparable efficacy to MTX and is safe and well tolerated. Metabolically stable antifolates are a promising therapeutic option that warrants further study.

Evaluation of the pharmacokinetics, preclinical and clinical efficacy of pralatrexate for the treatment of T-cell lymphoma.

INTRODUCTION: Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of T-cell neoplasms. Most patients with PTCL have a poor outcome with conventional therapies and are not cured without stem-cell transplantation. Pralatrexate, a novel antifolate chemotherapeutic agent, was rationally designed to impede folate metabolism by inhibiting dihydrofolate reductase (DHFR) and to be more efficiently internalized into tumor cells. Pralatrexate is the first drug that is FDA approved for patients with relapsed and refractory PTCL. AREAS COVERED: Pralatrexate has been used as a single agent and in combination with other agents in clinical trials for non-Hodgkin's lymphoma and Hodgkin's disease as well as in solid tumors. This review will cover the development of pralatrexate, the pharmacokinetics of pralatrexate, preclinical findings with pralatrexate and clinical studies of pralatrexate in hematologic malignancies. EXPERT OPINION: Pralatrexate has significant activity in vitro, and in early Phase I/II trials, responses were noted in patients with aggressive T-cell lymphomas. The Pralatrexate in Patients with Relapsed or Refractory Peripheral T-Cell Lymphoma trial demonstrated the activity of pralatrexate across a spectrum of heavily pretreated patients with different aggressive T-cell lymphoma subtypes, and studies in cutaneous T-cell lymphoma have shown efficacy at different doses and schedules. The most frequent adverse events in these trials were mucositis, reversible thrombocytopenia and fatigue.

Folotyn (pralatrexate injection) for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma: U.S. Food and Drug Administration drug approval summary.

PURPOSE: On September 24, 2009, the U.S. Food and Drug Administration granted accelerated approval for Folotyn (pralatrexate injection, Allos Therapeutics, Inc.) as a single agent for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma (PTCL); it is the first drug approved for this indication. EXPERIMENTAL DESIGN: This review was based on study PDX-008, a phase II, single-arm, nonrandomized, open-label, international, multicenter trial, designed to evaluate the safety and efficacy of pralatrexate when administered concurrently with vitamin B(12) and folic acid supplementation in patients with relapsed or refractory PTCL. RESULTS: The overall response rate was 27% in 109 evaluable patients [95% confidence interval (CI), 19-36%]. Twelve percent of 109 evaluable patients (95% CI, 7-20%)] had a response duration of ≥14 weeks. Six of these 13 patients achieved a complete response, and one patient had complete response unconfirmed. The most common grade 3 and 4 toxicities were thrombocytopenia, mucositis, and neutropenia. CONCLUSION: This accelerated approval was based on a response rate that is reasonably likely to predict clinical benefit in this heavily pretreated patient population with this rare disease. The applicant has committed to conducting postmarketing clinical trials to assess clinical benefit. The recommended starting dose of pralatrexate in patients with relapsed or refractory PTCL is 30 mg/m(2) via intravenous push over 3 to 5 min weekly for 6 weeks followed by a one-week rest (one cycle). Intramuscular injection of 1 mg vitamin B(12) should be administered every 8 to 10 weeks along with 1.0 mg folic acid given orally once a day.

Phase II-I-II study of two different doses and schedules of pralatrexate, a high-affinity substrate for the reduced folate carrier, in patients with relapsed or refractory lymphoma reveals marked activity in T-cell malignancies.

PURPOSE: To determine the maximum-tolerated dose (MTD) and efficacy of pralatrexate in patients with lymphoma. PATIENTS AND METHODS: Pralatrexate, initially given at a dose of 135 mg/m(2) on an every-other-week basis, was associated with stomatitis. A redesigned, weekly phase I/II study established an MTD of 30 mg/m(2) weekly for six weeks every 7 weeks. Patients were required to have relapsed/refractory disease, an absolute neutrophil greater than 1,000/microL, and a platelet count greater than 50,000/microL for the first dose of any cycle. RESULTS: The every-other-week, phase II experience was associated with an increased risk of stomatitis and hematologic toxicity. On a weekly schedule, the MTD was 30 mg/m(2) weekly for 6 weeks every 7 weeks. This schedule modification resulted in a 50% reduction in the major hematologic toxicities and abrogation of the grades 3 to 4 stomatitis. Stomatitis was associated with elevated homocysteine and methylmalonic acid, which were reduced by folate and vitamin B12 supplementation. Of 48 assessable patients, the overall response rate was 31% (26% by intention to treat), including 17% who experienced complete remission (CR). When analyzed by lineage, the overall response rates were 10% and 54% in patients with B- and T-cell lymphomas, respectively. All eight patients who experienced CR had T-cell lymphoma, and four of the six patients with a partial remission were positron emission tomography negative. The duration of responses ranged from 3 to 26 months. CONCLUSION: Pralatrexate has significant single-agent activity in patients with relapsed/refractory T-cell lymphoma.

A phase 1 study of pralatrexate in combination with paclitaxel or docetaxel in patients with advanced solid tumors.

PURPOSE: Pralatrexate is a rationally designed antifolate with greater preclinical antitumor activity than methotrexate. Pralatrexate was synergistic with paclitaxel and with docetaxel in mouse xenograft experiments. This phase 1 study was designed to determine the maximum tolerated dose and toxicity of pralatrexate plus paclitaxel or docetaxel in patients with advanced cancer. EXPERIMENTAL DESIGN: Pralatrexate was administered i.v. every 2 weeks (days 1 and 15) in a 4-week cycle. Depending on the taxane used and dose being tested, the taxane was administered on days 1 and 15; days 2 and 16; or days 1, 8, and 15. In the latter part of the study, patients in the docetaxel arm were treated with vitamin B(12) and folic acid supplementation to mitigate toxicity and allow pralatrexate dose escalation. RESULTS: For the combination of pralatrexate plus paclitaxel without vitamin supplementation, dose-limiting stomatitis and peripheral neuropathy were encountered at the lowest dose levels tested. For pralatrexate plus docetaxel plus vitamin supplementation, pralatrexate 120 mg/m(2) plus docetaxel 35 mg/m(2) administered on the same day every other week was defined as the maximum tolerated dose and schedule, with dose-limiting toxicities at higher dose combinations including stomatitis and asthenia. Significant antitumor activity was observed for this combination in patients with non-small-cell lung cancer. CONCLUSIONS: Pralatrexate (120 mg/m(2)) plus docetaxel (35 mg/m(2)) plus vitamin supplementation is well tolerated with signs of efficacy against non-small-cell lung cancer that merit phase 2 testing.

Phase II study of weekly edatrexate as first-line chemotherapy for metastatic breast cancer: a National Cancer Institute of Canada Clinical Trials Group study.

PURPOSE: The National Cancer Institute of Canada (NCIC) Clinical Trials Group conducted a phase II study to assess the efficacy and toxicity of edatrexate, a folate antagonist, in 35 patients with metastatic breast cancer. PATIENTS AND METHODS: The planned dose of edatrexate was 80 mg/m2/wk administered intravenously as first-line therapy. Prior adjuvant chemotherapy was allowed provided at least 12 months had elapsed from the completion of treatment to the development of recurrence. RESULTS: Mucositis was the dose-limiting toxicity in 34 assessable patients, resulting in a mean delivered dose-intensity of 57 mg/m2/wk. Other toxicities included myelosuppression, rash, pneumonitis, and increased AST. Side effects were generally mild to moderate. The complete plus partial remission rate (13 patients; 41%) was impressive. CONCLUSION: Edatrexate is an active agent against metastatic breast cancer, with acceptable toxicity. A lower than planned delivered dose-intensity was mainly due to mucositis.

Maternal drug therapy: effect on fetal and neonatal growth and neurobehavior.

Fetal and neonatal growth retardation may result in long term neurological and mental morbidity. There are multiple causes for intrauterine growth retardation but one etiology proposed is maternal drugs. In many instances it is difficult to determine if the growth retardation is due to the drugs or it is due to the disease process for which the mother receives the drugs. Weight and FOC appear to be more adversely effected than length. Combination drug therapy, for example anticonvulsant drugs, results in a greater incidence in teratology, growth retardation and lower IQ than monotherapy. Neurobehavior can also be adversely effected by maternal drugs. Although symptoms may be limited to the first months of life there is some evidence that this abnormal behavior is a reflection of in utero neurological insult which becomes evident later as poor organizational, perceptual, reading and mathematical skills or even mental retardation.