Nektar Therapeutics stock falls as NKTR-102 fails Phase III breast cancer study

Nektar Therapeutics (Nasdaq: NKTR) has announced that its Phase III study of NKTR-102 (etirinotecan pegol) in advanced breast cancer did not achieve statistical significance, causing its  shares to fall up to 13.5%.

The BEACON study evaluating single-agent NKTR-102 in patients with advanced breast cancer compared it to an active control arm of a single chemotherapy agent of physician’s choice (TPC) in patients heavily pre-treated with a median of three prior therapies for metastatic disease. NKTR-102 provided a 2.1-month improvement in median overall survival over TPC.

The therapy did, however, show greater improvement in certain pre-specified subgroups. In a pre-specified subgroup of patients with a history of brain metastases, NKTR-102 showed an improvement of 5.2 months in median overall survival, and in the subgroup of patients with baseline liver metastases at study entry, it showed an improvement of 2.6 months in median overall survival. In these patients with baseline liver metastases, the proportion of patients with 12-month survival was 46.9% in the NKTR-102 arm as compared to 33.3% in the control arm.