Synta Presents Positive Interim Results From ENCHANT-1 Trial Of Ganetespib

(RTTNews) - Synta Pharmaceuticals Corp. (SNTA) announced presentation of results from the ENCHANT-1 trial, a single-arm multi-center Phase 2 proof-of-concept study designed to evaluate ganetespib, the Company's lead drug candidate, administered as monotherapy for the treatment of metastatic breast cancer.

According to the company, the ENCHANT-1 trial is designed to evaluate the efficacy and safety of ganetespib monotherapy for treatment of HER2+ (Cohort A) or triple-negative (Cohort B) breast cancer (TNBC) patients previously untreated for locally advanced or metastatic disease. A third cohort was recently added to evaluate ganetespib in ER/PR+, HER2- (HER2-negative) patients.

The company noted that Target enrollment is 35 patients in each cohort, with an interim analysis planned at N=15. At the time of interim analysis conducted earlier this year, five patients were enrolled into the HER2+ cohort and 15 patients were enrolled into the TNBC cohort. Of these, four patients in the HER2+ cohort and 11 patients in the triple-negative cohort were evaluable by independent review for objective response, per proctocol.

Of the four patients in the HER2+ cohort evaluable for objective RECIST response by independent review, three patients (75%) achieved an objective response, including one complete radiological response (CR) and two partial responses or PR. One patient (25%) in this cohort achieved stable disease or SD.

Of the 11 patients in the TNBC cohort evaluable for objective RECIST response by independent review, two patients achieved PR (18%) and five patients achieved stable disease (SD, 45%), for a total disease control rate of 64%. As previously reported, one of the responding patients was adjudicated a clinical complete response at week 12 after receiving only three cycles of ganetespib therapy. Her disease was restaged to operable and she underwent a total mastectomy with curative intent. She is now receiving adjuvant chemotherapy.

At the week 3 PET assessment for metabolic response, three of the four patients (75%) evaluable by independent review in the HER2+ cohort achieved a metabolic response. In the triple-negative cohort, four of the 11 patients (36%) evaluable by independent review achieved a week 3 metabolic response.

"Results from ENCHANT-1 to date, while early, have demonstrated that ganetespib is clinically active as a single-agent in both HER2+ and triple-negative metastatic breast cancers.......The results suggest the exciting potential to realize a new category of treatment option for patients with advanced breast cancer, and we are looking forward to vigorously advancing development of ganetespib in breast cancer in order to bring this option to patients," said Iman El-Hariry, Vice President of Clinical Research at Synta.