Immunomedics says new data for lead drug IMMU-132 in triple-negative breast cancer (TNBC) keep it on course to file for accelerated approval in mid-2017.
Immunomedics' chief executive, Cynthia Sullivan, told investors at an R&D day yesterday that the prospects for the program "continue to improve as more confirmed results become available for the patients enrolled into our TNBC clinical trial."
The positive assessment comes after a difficult period for the program. Last year, Immunomedics' stock dipped after it reported preliminary data from its phase 2 trial in TNBC, and some investors have expressed concerns that manufacturing (CMC) issues could hold up the project.
Immunomedics took great pains to play down those anxieties at its R&D day, and analysts at Jefferies reckon that IMMU-132—also known as sacituzumab govitecan—"continues to look approvable in the U.S. based on phase 2 data" in TNBC, adding that there is "no apparent 'smoking gun' for CMC."
According to the latest data, median overall survival in patients on the drug is now almost 19 months, which lead investigator Linda Vahdat, M.D., of Weill Cornell Medical College described in a statement as "excellent results in this very advanced and heavily pre-treated group of patients who have exhausted virtually all therapeutic options."
Typically, median overall survival in patients receiving first-line therapy for TNBC is around 12 months. The latest crop of data in 85 patients also reveals that 81% of patients treated with the drug experienced tumor shrinkage with the proportion deemed to have a clinical benefit—defined as complete and partial remissions and stable disease—reaching 44% after six months, according to Immunomedics.
Vahdat was effusive about the drug, saying that she had "never seen these types of responses before" in this patient group and "if there was no alopecia, this would be a perfect therapy."
IMMU-132 is an antibody-drug conjugate, with the antibody portion of the drug latching on to tumors in order to dump a toxic payload that kills the malignant cells. It targets a receptor called Trop-2, which is found in multiple types of cancer, and Immunomedics also presented new results from trials of the drug in urothelial and lung cancers.
Immunomedics is in the throes of seeking a partner for IMMU-132, but there was little news on progress at the meeting, although the company said multiple parties were interested in licensing the drug. The company is hoping to make an announcement on that front prior to starting its phase 3 trial, which is due to get underway in the next few months.
On a sourer note for the biotech, Immunomedics is currently facing a shareholder revolt, with venBio striving to get four new directors onto the company's board at its next annual meeting on Feb. 16.
venBio—which says it owns around 9.9% of the company's stock and is its largest stockholder—claims Immunomedics' nominated candidates do not have the right experience to bring IMMU-132 forward.