Pasotuxizumab, a BiTE® immune therapy for castration-resistant prostate cancer: Phase I, dose-escalation study findings.

Aim: We report results of a first-in-human study of pasotuxizumab, a PSMA bispecific T-cell engager (BiTE®) immune therapy mediating T-cell killing of tumor cells in patients with advanced castration-resistant prostate cancer. Patients & methods: We assessed once-daily subcutaneous (SC) pasotuxizumab. All SC patients developed antidrug antibodies; therefore, continuous intravenous (cIV) infusion was assessed. Results: A total of 47 patients received pasotuxizumab (SC: n = 31, 0.5-172 µg/d; cIV: n = 16, 5-80 µg/d). The SC maximum tolerated dose was 172.0 µg/d. A sponsor change stopped the cIV cohort early; maximum tolerated dose was not determined. PSA responders occurred (>50% PSA decline: SC, n = 9; cIV, n = 3), including two long-term responders. Conclusion: Data support pasotuxizumab safety in advanced castration-resistant prostate cancer and represent evidence of BiTE monotherapy efficacy in solid tumors. Clinical trial registration: NCT01723475 (ClinicalTrials.gov).

A phase I study of pemetrexed (ALIMTA) and cyclophosphamide in patients with locally advanced or metastatic breast cancer.

PURPOSE: Determine the maximum tolerated dose (MTD) of pemetrexed and cyclophosphamide combination therapy for patients with locally advanced or metastatic breast cancer. EXPERIMENTAL DESIGN: Patients with locally advanced or metastatic breast cancer and WHO performance status 0 to 2 were eligible. Pemetrexed (range, 400-2,400 mg/m(2)) was administered on day 1 of a 21-day schedule followed by cyclophosphamide (range, 400-800 mg/m(2)). Folic acid and vitamin B(12) supplementation began 1 to 2 weeks before the first pemetrexed dose. RESULTS: Fifty-seven pretreated patients were enrolled and received 342 cycles (median, 4 cycles; range, 1-26) through 14 dose levels. The MTD of pemetrexed was 2,400 mg/m(2) (combined with cyclophosphamide, 600 mg/m(2)) with dose-limiting toxicities of grade 4 neutropenia with grade 4 infection and grade 3 diarrhea. Other grade 3 or 4 toxicities included (febrile) neutropenia, thrombocytopenia, anemia, elevated alanine aminotransferase/aspartate aminotransferase, and diarrhea. Pharmacokinetic analysis indicated that pemetrexed clearance and central volume of distribution were 40% lower than single-agent reference data, yielding a 68% increase in total systemic exposure and a 56% increase in maximal plasma concentration. Among the 50 patients evaluable for efficacy, 13 (26%) patients had a partial response and 17 (34%) patients had stable disease. CONCLUSIONS: Pemetrexed was generally well tolerated. The observed toxicities were consistent with the known toxicity profiles of pemetrexed and cyclophosphamide. Considering the MTD and the toxicity and efficacy results in this and prior studies, a low (600 mg/m(2)) and a high (1,800 mg/m(2)) dose of pemetrexed with cyclophosphamide (600 mg/m(2)) will be evaluated in the consecutive prospective randomized phase II study.

Overview of phase I/II pemetrexed studies.

Pemetrexed (Alimta) is an antifolate that is effective in the inhibition of multiple enzyme targets including thymidylate synthase, dihydrofolate reductase, and glycinamide ribonucleotide formyl transferase. The compound has been evaluated in several phase I trials, both as single agent and in combination with other cytotoxic agents. The initial schedule selected for further investigation in phase II trials was pemetrexed 600 mg/m2 as a 10-minute infusion on day 1 every 21 days. During the subsequent phase II development the dose of pemetrexed was adjusted to 500 mg/m2 due to bone marrow and gastrointestinal toxicities. The adjusted dose of pemetrexed was well tolerated throughout the late-phase drug development program. Preclinical evidence suggests that pemetrexed has additive or synergistic activity when combined with many other clinically important anticancer agents, including gemcitabine (Gemzar), fluorouracil, carboplatin (Paraplatin), oxaliplatin (Eloxatin), paclitaxel, and vinorelbine (Navelbine). Dose-limiting toxicities in these studies were primarily hematologic, and there was no evidence of cumulative hematologic toxicity. During the drug development program it was discovered that supplementation with folic acid and vitamin B12 profoundly increased the tolerability of pemetrexed. The studies discussed in this review demonstrate that pemetrexed is well tolerated as a single agent and will be an important contribution to combination chemotherapy regimens.

Chemoembolization with cisplatin, lipiodol and Gelfoam and subsequent systemic chemotherapy with cisplatin and interferon in patients with hepatocellular carcinoma: a non-randomized prospective study.

Arterial chemoembolization with subsequent systemic chemotherapy was assessed prospectively. Of 94 consecutive patients with HCC, 31 patients were considered to have inoperable disease and were selected for chemoembolization. Twenty-two of the 31 patients underwent chemoembolization. In eight patients, technical problems with catheterization prevented the application of therapy, and one patient rejected further treatment. Regimen: Three monthly cycles of chemoembolization with cisplatin 20 mg/m(2) mixed with lipiodol delivered intraarterially with Gelfoam or collagen on day 1, followed by intravenous chemotherapy with cisplatin 60 mg/m(2) on day 2; interferon alpha-2c 30 microg (10 M IU) subcutaneously on days 2, 5, 9, and 12. Three percent of the patients (1/31) (CI 95% 0.08; 16.7) experienced a partial clinical response, in 53% alpha-fetoprotein levels decreased by more than 50%. On univariate analysis, performance status, Child score, Okuda stage, albumin levels, and lactate dehydrogenase were found to have an effect on survival. Postchemoembolization syndrome occurred in 68% of the patients, nausea/vomiting grades 3/4 (according to the World Health Organization WHO) in six patients, anemia grade 3 in three patients, leukopenia grade 3 in one patient and thrombocytopenia grade 3 in one patient. This treatment regimen is a very selective procedure. Because of the low response rate it is not recommended for routine clinical use.