Geron Corp. (GERN) announced that, on the basis of an unplanned interim analysis, it is discontinuing its randomized Phase 2 study of imetelstat in metastatic HER2-negative breast cancer because median progression-free survival or PFS in the imetelstat arm was shorter than in the comparator arm.
The company also announced that it is continuing its randomized Phase 2 study of imetelstat in advanced non-small cell lung cancer or NSCLC.
However, the company said that although a separate interim analysis of the NSCLC study suggested a modest trend of efficacy in favor of the imetelstat arm, the pre-specified success criteria in this trial are unlikely to be met, and, as a consequence, it is doubtful that Geron will take imetelstat forward into Phase 3 development for NSCLC.
The study in metastatic HER2-negative breast cancer was a randomized, controlled trial of 166 patients in which imetelstat was evaluated in combination with paclitaxel, compared to paclitaxel alone. The primary efficacy endpoint was an estimate of PFS.
In this trial, a scheduled periodic review conducted by Geron's Internal Safety Monitoring Committee reported a greater number of deaths and number of patients discontinuing paclitaxel in the imetelstat arm compared to the control arm.
Based on these observations, an unplanned interim analysis of efficacy was performed that showed a median PFS of 6.2 months for patients receiving treatment with imetelstat in combination with paclitaxel, compared to 8.0 months for patients receiving paclitaxel alone (hazard ratio = 1.62; p = 0.028).
The company said it is evaluating imetelstat in two hematologic malignancies: essential thrombocythemia or ET and multiple myeloma. Using biomarkers, these two studies are designed to evaluate whether inhibiting telomerase will selectively reduce the proliferation of the malignant progenitor cells responsible for these diseases. In the ET trial, the company is also evaluating clinical and hematological responses. Geron continues to expect to release top-line results from these studies in the fourth quarter of this year.
by RTT Staff Writer
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