Geron Discontinues Imetelstat Breast Cancer Trial, Expects to Halt NSCLC Development

Based on an unplanned interim analysis, Geron Corporation (NASDAQ:GERN) announced Monday morning that it will be discontinuing a Phase II study of its developmental drug Imetelstat against metastatic HER2-negative breast cancer. In the study, patients receiving the treatment along with paclitaxel had a lower Progression Free Survival (PFS) than patients receiving paclitaxel alone. After a safety monitoring committee reported a greater number of deaths in the Imetelstat arm of the trial, and an increase in the number of patients discontinuing treatment, an interim analysis was conducted that deemed the study unfit to continue. Imetelstat is, however, still in a Phase 2 trial for the treatment of Non-Small Cell Lung Cancer (NSCLC), which has shown a very slight increase in median PFS compared to the control arm (2.8 months vs. 2.6 months). Although the data for the NSCLC trial shows slight improvement, the company guides that its is unlikely the trial will reach its primary endpoints, and Imetelstat will be probably be discontinued as a treatment for NSCLC

Geron is still developing Imetelstat for two hematologic malignancies – essential thrombocythemia and multiple myeloma – which have been unaffected by the poor trial results and have yet to show negative data. The company expects to release top-line results from those studies during the fourth quarter. Besides the disappointment of fruitless R&D spending, today’s announcement comes as a blow to the Imetelstat franchise, essentially eliminating half of the potential indications for the oncology drug and millions in possible revenue. Given the severity of today’s news, share price will be weak while analysts reevaluate Imetelstat’s market opportunity and the potential of its other candidate  GRN-1005. The drug is in Phase 2 trials for NSCLC and breast cancer with metastases in the brain. It delivers paclitaxel across the blood-brain barrier, a difficulty for many cancer treatments. Ahead of the bell, GERN is down 47%.

See PropThink’s GERN coverage last week by clicking here.