Nektar Therapeutics (NASDAQ: NKTR) today announced that enrollment is complete in the pivotal clinical study of etirinotecan pegol (NKTR-102) in patients with metastatic breast cancer. The Phase 3 study, also known as the BEACON trial, is evaluating etirinotecan pegol versus a single-agent treatment of physician's choice for the treatment of locally recurrent or metastatic breast cancer. Etirinotecan pegol is the first long-acting topoisomerase I inhibitor designed to concentrate in tumor tissue to provide sustained tumor suppression throughout the entire chemotherapy cycle.
"Strong interest in etirinotecan pegol and the BEACON study from investigators and patients has allowed us to rapidly complete our recruitment and enrollment," said Robert Medve, MD, Senior Vice President and Chief Medical Officer of Nektar Therapeutics. "We recognize the high unmet need for new treatment options in the metastatic breast cancer setting, particularly among patients with HER2-negative breast cancer whose disease has progressed following anthracycline, taxane and capecitabine therapies. The primary endpoint in the BEACON study is survival and as we have previously announced, we plan to conduct an interim futility analysis for the BEACON study in the first quarter of next year with topline survival data to be available around the end of 2014."
Positive Phase 2 data for etirinotecan pegol was previously announced and presented at the ASCO 2011 Breast Cancer Symposium (Garcia et. al., ASCO 2011). Etirinotecan pegol achieved a confirmed objective response rate by RECIST of 29 percent. In addition, 71 percent of patients in the study had no tumor progression, defined as complete response (CR), partial response (PR) and stable disease (SD), as measured by RECIST criteria. Etirinotecan pegol also demonstrated a high clinical benefit rate (CR+PR+SD greater than six months) of 46 percent (30 of 66). Six patients experienced 100 percent resolution of all target lesions, with two complete RECIST responses and four near-complete responses. Patients treated exhibited minimal alopecia, neuropathy and neutropenia, which are significant adverse events associated with existing breast cancer therapies. Side effects were generally manageable; the most common Grade 3 toxicity was diarrhea (17-23%) typically occurring after three months of therapy for both schedules.