A phase II study of bryostatin-1 and paclitaxel in patients with advanced non-small cell lung cancer

Background: Bryostatin-1 is a macrocyclic lactone, which exhibits pleiotropic biological effects via protein kinase C and has shown preclinical synergy with paclitaxel for enhanced tumor cell apoptosis. Patients and Methods: Patients had stage IIIB (pleural effusion)/IV non-small cell lung cancer, measurable disease, performance status 0-2 Eastern Cooperative Oncology Group, adequate organ function, and no prior chemotherapy. Patients received dexamethasone premedication followed by paclitaxel at a dose of 90 mg/m² on days 1, 8, and 15 along with bryostatin-1 50 μg/m² on days 2, 9, and 16 every 28 days until disease progression. Correlative assays measuring serum levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and T-lymphocyte numbers were performed based on a previous study showing cytokine induction in vivo by bryostatin-1. Fifteen patients were enrolled. Results: Thirty cycles of the bryostatin-1 and paclitaxel were delivered with a median of 2 per patient (range 1-4). Myalgia was the predominant non-hematologic toxicity encountered as 3 patients developed grade 4 and 1 patient developed grade 3 myalgia. Four patients were removed from the study during cycle 1 for rapid disease progression or myalgia. Eleven patients could be evaluated for response. Five patients had stable disease, two had a mixed response, and four had progressive disease. Ten patients received second-line chemotherapy after leaving the study. Median survival was 31 weeks (95% confidence interval: 5.4-49.3). Correlative data showed a trend towards decreased plasma IL-6 and TNF-α after each cycle of therapy presumably due to the dexamethasone premedication and/or paclitaxel. Conclusions: This drug combination showed no significant clinical response and was associated with reproducible toxicity. The predominance of myalgia in the absence of elevated serum cytokines suggests a non-inflammatory etiology of this toxicity.