A phase II trial of ixabepilone in Asian patients with advanced gastric cancer previously treated with fluoropyrimidine-based chemotherapy

PURPOSE

The highest rates of gastric cancer occur in Eastern Asia. Fluoropyrimidine-based therapy is used initially in unresectable and metastatic disease, but no single standard of care exists following disease progression. Ixabepilone, an epothilone B analog, is a non-taxane microtubule-stabilizing agent with clinical activity across multiple tumor types approved by the United States Food and Drug Administration for treatment of metastatic breast cancer.

METHODS

Asian patients with unresectable or metastatic gastric adenocarcinoma who had failed fluoropyrimidine-based chemotherapy received ixabepilone 40 mg/m(2) by 3-h intravenous infusion every 3 weeks. The primary endpoint was objective response rate (ORR).

RESULTS

Fifty-two patients were treated (65.4 % men; median age: 56.5 years). The ORR was 15.4 % (95 % confidence interval [CI] 6.9-28.1); 8 patients achieved partial responses for a median duration of 3.1 months (95 % CI 2.6-4.1 months) and 26 patients (50.0 %) had stable disease. Median progression-free survival was 2.8 months (95 % CI 2.1-3.5 months). The most common grade 3 non-hematological toxicities were fatigue (9.6 %), decreased appetite (7.7 %), sensory neuropathy (5.8 %), and diarrhea (5.8 %). Grade 3/4 neutropenia occurred in 46.2 % of patients.

CONCLUSIONS

Ixabepilone is active in Asian patients with advanced gastric cancer and shows a toxicity profile similar to those previously reported in other tumor types.

CA184-161: A phase I/II trial of vemurafenib and ipilimumab in patients with BRAF V600 mutation-positive metastatic melanoma

TPS8603

Background: Ipilimumab (ipi) is a fully human monoclonal antibody that blocks cytotoxic T-lymphocyte antigen-4 (CTLA-4) to augment antitumor immune responses. Ipi significantly improved overall survival (OS) in two separate phase III trials of metastatic melanoma (MM): (1) at 3 mg/kg as monotherapy in previously treated patients and (2) at 10 mg/kg combined with dacarbazine in previously untreated patients. The most common drug-related adverse events with ipi were immune-related, and were generally reversible using treatment guidelines. Vemurafenib (vem) is a potent inhibitor of BRAF V600E-mutated kinase, which occurs in ~50% of MM. In clinical studies, vem produced objective response rates of ~50% with a significant improvement in the rate of OS in patients with previously untreated BRAF V600-positive MM. The purpose of this phase I/II study is to determine the safety and feasibility of ipi plus vem in patients with BRAF V600-positive MM, and to evaluate the efficacy of the combination in comparison to historical results observed with each agent alone. Methods: In phase I, an escalating dose design is used to assess safety/tolerability and to determine the maximum tolerated dose (MTD) of each agent. Vem will initially be given alone for 28 days at 960 mg p.o. BID, followed by vem in combination with ipi i.v. at 3 mg/kg [induction (q3w x 4) and maintenance (q12w)]. The next cohort will receive vem at 960 mg plus ipi increased to a dose of 10 mg/kg. Phase I will enroll an estimated 20 patients who have not previously received a CTLA-4 antagonist or BRAF inhibitor. If new or heightened frequency or severity of toxicities is not observed, a phase II single-arm extension at the MTD of each agent will be conducted in patients with previously untreated MM. The primary objectives of phase II (estimated enrollment of 30 patients) are to obtain preliminary evidence of efficacy (OS, 1- and 2-year survival rates) and to evaluate safety of the combination. Major inclusion criteria are ≥ 18 years of age, BRAF V600-positive MM, measurable tumor, no active brain metastasis, and an ECOG PS of 0-1. The first patient was enrolled in November 2011 and enrollment is ongoing (ClinicalTrials.gov identifier: NCT01400451).

Dasatinib plus SMO antagonist versus dasatinib alone for treating patients (pts) with newly diagnosed Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia in chronic phase (CML-CP): Design of CA180-363, a phase II, open-label randomized trial

TPS6634

Background: Dasatinib 100 mg once daily (QD) is approved as first-line therapy for pts with newly diagnosed Ph+ CML-CP and those who are resistant or intolerant to prior therapy, including imatinib, based on demonstrated efficacy and tolerability. BMS-833923 (SMO antagonist), selectively blocks hedgehog (Hh) pathway signaling by binding to and antagonizing Smoothened (SMO), preventing downstream signaling and activation of target genes. In preclinical studies, SMO loss or inhibition reduces hematopoietic stem cell renewal, induces CML stem cell depletion, and inhibits imatinib-resistant CML cell growth (Dierks, Cancer Cell 2008; Zhao, Nature 2009). In pts with CML, Hh signaling genes (Sonic hedgehog, SMO, and Gli1) are significantly upregulated compared with control pts (Long, J Exp Clin Cancer Res 2011), suggesting that drug resistance and disease recurrence may be overcome by targeting the Hh signaling pathway. Methods: CA180-363 is a phase 2 trial to assess dasatinib activity with or without SMO antagonist in pts with newly diagnosed Ph+ CML-CP. Pts receive dasatinib 100 mg QD for 12 months and are then randomized 1:1 to continuing dasatinib 100 mg QD with or without SMO antagonist up to 24 months, followed by dasatinib 100 mg QD alone until end of study (60 months). Randomization is stratified by Sokal score at diagnosis and major molecular response (MMR) at 12 months (yes/no). Eligible pts are aged ≥18 years, have an Eastern Cooperative Group (ECOG) performance status of 0-2, and previously untreated Ph+ CML-CP diagnosed within 6 months of enrollment. Primary endpoint (evaluated in pts who do not achieve MMR prior to randomization) is comparison of MMR rates for dasatinib alone vs dasatinib plus SMO antagonist. Other endpoints (evaluated in all pts) are complete molecular response, progression-free survival, event-free survival, transformation-free survival, and safety of the combination regimen. Recruitment started in September 2011 (14 pts enrolled to date); estimated primary completion date is November 2014. ClinicalTrials.gov ID: NCT01357655.