Immunomedics has announced that its Phase 3 ASCENT trial of Trodelvy (sacituzumab govitecan) met its main goal of demonstrating that the medication is superior to standard chemotherapy at delaying disease progression and prolonging the survival of people with metastatic triple-negative breast cancer (mTNBC).
The biopharmaceutical company had closed ASCENT (NCT02574455) early, in April, due to the strong evidence already gathered of Trodelvy’s ability to halt disease progression in these patients.
“The results of the global Phase 3 ASCENT study confirm our initial observations that sacituzumab govitecan has the potential to change the standard management of mTNBC,” Aditya Bardia, MD, MPH, principal investigator of ASCENT, said in a press release. Bardia also is director of precision medicine at the Center for Breast Cancer at the Massachusetts General Hospital Cancer Center and an assistant professor of medicine at Harvard Medical School,
“Based on these data, sacituzumab govitecan has set a new benchmark in scientific and clinical innovation for patients with mTNBC by offering a novel alternative to the common drugs currently in clinical practice,” Bardia said.
Trodelvy is a targeting agent called an antibody-drug conjugate, which is made up of an antibody targeting TROP-2 — a protein found in different types of tumors, including more than 90% of those in TNBC patients — that is linked to a toxic compound. Once the antibody binds to cancer cells that produce the TROP-2 protein, the toxic compound is released, eliminating them.
The U.S. Food and Drug Administration recently approved Trodelvy, under its accelerated approval program, as a third-line treatment for people with mTNBC.
That approval was based on data from 108 TNBC patients who participated in the Phase 1/2 IMMU-132 trial (NCT01631552). Those findings showed that Trodelvy was able to shrink tumors in 33% of the paticipants and elicit responses lasting a median of 7.7 months.
Trodelvy’s continued approval was pending confirmation of these findings in a larger, Phase 3 confirmatory trial. ASCENT was designed under the FDA’s special protocol assessment (SPA) to validate earlier safety and efficacy data and thereby support Trodelvy’s accelerated approval.
The main goal of the study was to assess if Trodelvy could be superior to standard chemotherapy at delaying disease progression or death in individuals with advanced TNBC who had received at least two prior lines of treatment.
The secondary goals included assessing the therapy’s effect on patients’ overall survival, treatment response, and duration of response.
Top-line data from ASCENT, now announced by the company, showed that the study indeed met its main goal, with Trodelvy prolonging the time patients lived without showing signs of disease progression from a median of 1.7 to 5.6 months.
Trodelvy also was found to be superior to standard chemo at prolonging the time patients lived and eliciting treatment responses.
“It is gratifying to see the final confirmatory results of Trodelvy in a randomized study supporting the previously reported Phase 2 data that formed the basis of the accelerated approval of Trodelvy,” said Behzad Aghazadeh, executive chairman of Immunomedics.
The medication’s safety profile also was found to be consistent with previous studies and with its approved prescribing information. Neutropenia, or low white blood cell counts, and diarrhea were the most common severe (grade 3) or life-threatening (grade 4) adverse events observed. No new safety concerns were identified in ASCENT.
“The ASCENT topline data also validate the manageable safety profile of sacituzumab govitecan, rendering it a good partner candidate for combination with other therapies, including immunotherapy,” Bardia said.
Immunomedics is now planning to submit a supplemental biologics licence application (sBLA) to the FDA later this year requesting full approval of Trodelvy for this indication.
“Given the poor prognosis associated with mTNBC, we are excited that Trodelvy demonstrated improved clinical outcomes for these patients,” said Loretta M. Itri, chief medical officer of Immunomedics.
“We look forward to presenting full results at an upcoming medical conference, as well as sharing them with the FDA in support of the full approval of Trodelvy in this difficult-to-treat cancer,” Itri added.