Immunomedics announces new data for sacituzumab govitecan (IMMU-132) to treat metastatic triple-negative breast cancer.

Immunomedics, Inc. announced new data for sacituzumab govitecan (IMMU-132) during the Company�s Investor R&D Day. IMMU-132 is Immunomedics� proprietary solid tumor therapy candidate that is advancing through development in four indications: metastatic triple-negative breast cancer (TNBC), the lead indication and for which the FDA has awarded Breakthrough Therapy Designation; urothelial cancer (UC); small-cell lung cancer (SCLC); and non-small-cell lung cancer (NSCLC). Immunomedics expects to submit a Biological License Application (BLA) to the FDA for accelerated approval of IMMU-132 in TNBC patients in mid-2017.

IMMU-132 has been studied in over 410 diverse cancer patients, with the dose of 10 mg/kg given on days 1 and 8 of repeated 21-day cycles being the established dose regimen. Some patients have been treated for more than a year.Immunomedics disclosed results in 85 assessable TNBC patients. These results will be part of the BLA submission for the accelerated approval of IMMU-132. The Company announced last month that it had achieved the goal of enrolling 100 TNBC patients, as requested by FDA for this BLA filing.

The Company reported that the objective response rate and median progression- free survival (PFS, intention-to-treat, or ITT, basis) have been maintained with these additional patient results, while the median overall survival (OS also on ITT basis) has been extended to almost 19 months. These patients experienced two complete and 23 partial responses, while an additional three patients with initial partial responses are awaiting confirmation. Overall, 81% of patients treated with IMMU-132 showed tumor shrinkage from baseline measurements. The clinical benefit rate (complete and partial remissions, and patients with stable disease) at six months or later computed to 44%. The median duration of response for those with objective responses was almost 11 months. It was emphasized that these are interim results, since 20 patients are continuing treatment; a final outcome must await analysis of all patients enrolled.The major toxicity (grade more than 3) has been neutropenia (39%) in this and most cancer patient cohorts, which has been manageable by dose reduction, dose delays, or giving a hematopoietic cytokine. Diarrhea, which is the major side effect with irinotecan, the parent drug from which SN-38 is derived, has been much less, such as a grade more than 3 of 13%.