The U.S. Food and Drug Administration (FDA) is reviewing Genentech’s request for Tecentriq (atezolizumab) to be approved, in combination with the chemotherapy Abraxane (nab-paclitaxel), as a first-line treatment for certain triple-negative breast cancer patients.

The supplemental Biologics License Application (sBLA), which covers surgery-ineligible patients with locally advanced or metastatic triple negative breast cancers (TNBCs) that produce the PD-L1 factor, was priority review status. A decision is expected by March 12.

“Tecentriq in combination with nab-paclitaxel [Abraxane] has the potential to meaningfully advance treatment for people with PD-L1-positive, metastatic triple-negative breast cancer. People need more options for this type of breast cancer, which is particularly difficult to treat,” Sandra Horning, MD, chief medical officer and head of Global Product Development, said in a press release.

If approved, the combination will be the first cancer immunotherapy for PD-L1-positive, metastatic TNBC.

Tecentriq, developed by Genentech, is an antibody that selectively targets PD-L1, a protein produced by cancer cells to evade immune surveillance. It is approved for some patients with metastatic urothelial carcinoma (bladder cancer) or non-small cell lung cancer.

Abraxane is a kind of injectable nanoparticle in which the chemotherapy paclitaxel is bound to the protein albumin, which works as a delivery vehicle. The approach is approved for metastatic breast cancer, non-small cell lung cancer, and pancreatic cancer.

The application is supported by results from the IMpassion130 trial Phase 3 trial (NCT02425891), where the combination led to longer survival times and delayed disease worsening or death in PD-L1-positive TNBC patients, compared to Abraxane alone.

IMpassion130 recruited 902 patients across 41 countries in Europe, the U.S., Canada, Asia, Latin America, and Australia. Participants were randomly assigned Tecentriq or a placebo — given every two weeks — along with weekly Abraxane at a schedule of three weeks on, one week off.

Treatment was given until patients experienced signs of unacceptable toxicity or disease progression.

The trial’s main goals were to determine if the Tecentriq combination was better than Abraxane alone at delaying disease progression and extending survival in TNBC patients regardless of their PD-L1 status, and in a subpopulation of patients whose tumors produced the PD-L1 factor.

In the entire study population, Tecentriq-Abraxane combo extended the median time to disease progression or death to 7.2 months from 5.5 months with Abraxane alone. The combination also prolonged median overall survival from 17.6 to 21.3 months, but the difference did not reach statistical significance.

Almost half (40.9%) of enrolled patients had PD-L1–positive tumors, and they seemed to benefit most from the combo treatment. These patients lived for a median of 25 months, and were alive and progression-free a median of 7.5 months, compared to 15.5 months survival and 5 months progression-free survival in the Abraxane (control) group.

Their risk of death or disease worsening was reduced by 38%.

Combo treatment also led to a higher number of patients showing tumor shrinkage (objective response rate) compared to the control group — 56.0% vs. 45.9%.

Again, this effect was more pronounced in the PD-L1–positive group, where 58.9% of patients also given Tecentriq saw their tumors shrink, compared to 42.6% in the Abraxane group.

The combo treatment was well-tolerated without any unexpected adverse effects, according to researchers. Serious adverse effects were detected at similar rates between the Tecentriq (23%) and the Abraxane group (18%). These side effects were consistent with the toxic effects of Tecentriq and Abraxane known from prior studies.

“We are working closely with the FDA to bring this Tecentriq combination to people with PD-L1-positive, metastatic triple-negative breast cancer as soon as possible,” Horning added.

IMpassion130 is one of the seven Phase 3 trials currently investigating Tecentriq in TNBC in both early and advanced stages of the disease.