Phase II, Double-Blinded, Randomized Study of Enzastaurin Plus Pemetrexed as Second-Line Therapy in Patients with Advanced Non-small Cell Lung Cancer

Introduction

We examined the efficacy of enzastaurin plus pemetrexed as second-line therapy in patients with advanced (stage IIIA/B or IV) non-small cell lung cancer in a double-blinded, randomized, phase II study.

Methods

Patients received pemetrexed 500 mg/m² intravenously on day 1 of 21-day cycles (day 8 in cycle 1) plus oral enzastaurin (250 mg two times per day; combination arm) or placebo (pemetrexed arm). Both arms received supplementation with vitamin B₁₂, folic acid, and dexamethasone. An interim analysis was conducted to determine whether efficacy would warrant a phase III study.

Results

The interim analysis showed no evidence of improved progression-free survival with enzastaurin. At final analysis (N = 160, 80 in each arm), baseline characteristics were well balanced. There was no significant difference in progression-free survival (3.0 months, p = 0.544) or overall survival (9.6 months in combination arm and 7.4 months in pemetrexed arm, p = 0.171). Drug-related serious adverse events included cerebrovascular accident, palpitations, and renal failure (n = 1, each) in combination arm and neutropenic sepsis, thrombocytopenia, and panniculitis (n = 1, each) in pemetrexed arm. Nonhematologic drug-related grade 3/4 toxicities were similar in both arms. Grade 3/4 hematologic toxicities were higher with the combination, specifically leukopenia (6.3% versus 0%), neutropenia (15.2% versus 5.0%), and thrombocytopenia (8.9% versus 1.3%). Of the 26 deaths reported on-study or within 30 days of discontinuation (10 in combination arm and 16 in pemetrexed arm), none were drug related.

Conclusion

The combination regimen of enzastaurin and pemetrexed is well tolerated but does not improve efficacy over pemetrexed and placebo as second-line treatment of unselected patients with advanced non-small cell lung cancer.