Phase 3 ASCENT Trial in Metastatic TNBC Meets Primary End Point of PFS

July 6, 2020
Kristie L. Kahl

The phase 3 ASCENT trial designed to evaluate sacituzumab govitecan-hziy in patients with brain metastasis-negative, metastatic triple-negative breast cancer met its primary end point of progression-free survival.

The phase 3 ASCENT trial – designed to evaluate sacituzumab govitecan-hziy (Trodelvy) in patients with brain metastasis-negative, metastatic triple-negative breast cancer (mTNBC) who have previously received at least 2 prior therapies for metastatic disease – met its primary end point of progression-free survival (PFS), according to Immunomedics, Inc.

Moreover, the trial reached its secondary end points of overall survival (OS) and objective response rate (ORR). Sacituzumab govitecan-hziy is the first antibody drug conjugate to demonstrate improved outcomes in those with relapsed or refractory mTNBC who received 2 prior therapies.

“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,” study principal investigator Aditya Bardia, MD, MPH, director of precision medicine at the Center for Breast Cancer at Massachusetts General Cancer Center and assistant professor of medicine at Harvard Medical School, said in a press release.

“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,” he added. “Importantly, 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.”

The international, open-label confirmatory phase 3 study (NCT02574455) was designed under an FDA Special Protocol Assessment to validate the safety and efficacy activity of sacituzumab govitecan-hziy to support its accelerated approval.

Patients were randomized to receive either sacituzumab govitecan-hziy or a physician’s choice of chemotherapy. The primary end point was PFS, while secondary end points included OS, ORR, duration of response (DOR), time to onset of response, and other measures of safety and tolerability.

The agent demonstrated a statistically significant improvement in PFS compared to chemotherapy (HR, 0.41; 95% CI, 0.32-0.52), with a median PFS of 5.6 months (95% CI, 4.3-6.3), compared to 1.7 months (95% CI, 1.5-2.6) for chemotherapy (P < .0001).

The safety profile of sacituzumab govitecan-hziy in the trial appeared to be consistent with the FDA-approved label for the drug. Neutropenia and diarrhea were the most common grade 3/4 adverse events. Moreover, no new safety signals were observed.

Full results will be presented at an upcoming medical conference, according to Immunomedics.

Trodelvy was recently approved by the FDA as a third-line treatment for adult patients with mTNBC under the FDA’s Accelerated Approval Program, based on the ORR and DOR reported from a single-arm, multicenter phase 2 study. The supplemental biologics license application submission for sacituzumab govitecan-hziy is seeking full approval later this year.

“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. These results provide important additional information for patients and their treating physicians to understand the definitive benefits they are deriving,” Behzad Aghazadeh, PhD, executive chairman of Immunomedics, said in the release. “Importantly, the strong ASCENT data reinforce the promise of our unique ADC technology and embolden us to continue our work to change the treatment paradigm for patients with difficult-to-treat cancers.”

Reference:

Immunomedics. Immunomedics Announces Positive Results from Phase 3 ASCENT Study of TRODELVY. Published July 6, 2020. https://www.immunomedics.com/our-company/news-and-events/immunomedics-announces-positive-results-from-phase-3-ascent-study-of-trodelvytm/. Accessed July 6, 2020.