A phase II evaluation of nintedanib (BIBF-1120) in the treatment of recurrent or persistent endometrial cancer: an NRG Oncology/Gynecologic Oncology Group Study

Introduction: Patients presenting with advanced, recurrent, or metastatic endometrial cancer have limited treatment options. On behalf of the Gynecologic Oncology Group, we conducted this phase II trial of nintedanib (BIBF 1120), a potent small molecule triple receptor tyrosine kinase inhibitor of PDGFR α and β, FGFR 1/3, and VEGFR 1-3, in this population.

Objectives: The primary objectives were to estimate event-free survival (EFS) at 6 months and the proportion of patients who have an objective tumor response. In addition, we sought to determine the nature and degree of toxicity. Secondary objectives were to estimate progression-free and overall survival.

Methods: This was a two-stage, single-arm phase II study. Eligible patients were treated with single-agent nintedanib at a dose of 200mg twice daily.

Results: Of 37 patients enrolled, 32 were eligible. There were zero complete and three partial responses for an overall response rate of 9.4% (90% 2-sided CI=2.6-22.5%). Seven patients (21.9%; 90% 2-sided CI=10.7-37.2%) were EFS at 6 months, with one patient continuing on study at the time of this writing. Serious toxicity included the following grade 3 events: gastrointestinal toxicity (5), neutropenia (1), edema (1), hypertension (1), and liver function abnormalities (5).

Conclusions: Nintedanib lacked sufficient activity as a single agent to warrant enrollment to second stage. However, preclinical data indicate it may be synergistic with paclitaxel in a population of patients enriched for specific p53 mutations that result in loss of function. Subsequent studies may evaluate this agent in combination with paclitaxel.