The U.S. Food and Drug Administration (FDA) has rejected Immunomedics’ application for accelerated approval of sacituzumab govitecan as third-line treatment for advanced triple-negative breast cancer (TNBC), the company announced.
The issues pointed out by the FDA were “exclusively focused on Chemistry, Manufacturing and Control matters,” Michael Pehl, president and CEO of Immunomedics, said in a press release. Thus, no new preclinical and clinical data will need to be generated.
The company is now planning a meeting with the FDA to discuss the agency’s requirements and timelines for a new Biologics License Application submission and approval of this investigational TNBC therapy.
“We believe in sacituzumab govitecan’s potential to be a viable treatment option for these patients,” Pehl said. ”We will work closely with the FDA with the goal of bringing this important medicine to patients as soon as possible.”
Sacituzumab govitecan is a compound that combines an antibody against the TROP-2 protein — found in many tumor types, including in more than 90% of TNBC patients — with a toxic payload. Once bound to its target, sacituzumab govitecan releases the toxic compound into cancer cells, triggering their death.
Immunomedics’ application was supported by data from a Phase 1/2 trial (NCT01631552), where sacituzumab govitecan reduced tumor burden in 34% of metastatic TNBC patients — 3% saw their cancer disappear.
The trial included 110 patients who had received at least two prior treatments for their metastatic disease. Responses lasted a median of 7.6 months and patients lived without disease progression for a median of 5.5 months — although 11 patients lived without disease worsening for more than 12 months. The median overall survival was 12.7 months.
Treatment was also well-tolerated, with no treatment-related deaths and two patients discontinuing due to toxicity. The most common serious adverse events were low levels of blood cells, such as neutrophils, leukocytes, and red blood cells.
Immunomedics is now conducting a larger study — the ASCENT Phase 3 trial (NCT02574455) — to confirm that sacituzumab govitecan is better at delaying disease worsening or death than standard treatments.
The trial is recruiting around 490 participants with metastatic TNBC who failed to respond or relapsed after at least two prior treatments. Patients are enrolled at sites in the United States, Canada, France, Belgium, Spain, the United Kingdom, and Germany. Participating centers in the U.S. can be found here.