Roche wins first US approval of immunotherapy for breast cancer – STAT

Source: Roche wins first US approval of immunotherapy for breast cancer – STAT

Roche’s cancer immunotherapy Tecentriq (atezolizumab), a PD-L1 inhibitor, scored its fifth Food and Drug Administration approval on Friday, for advanced triple-negative breast cancer, but the fifth was a first: Before this decision, no immunotherapies had been approved for any form of breast cancer.

The approval, as is typical, was narrow: for locally advanced or metastatic triple-negative breast cancer expressing PD-L1, the molecule that locks onto PD-1 receptors on the surface of T cells. (Triple-negative means the tumor cells do not have estrogen receptors, progesterone receptors, or HER2, all of which fuel uncontrolled cell proliferation but can be blocked with drugs such as Herceptin.)

The PD-L1/PD-1 handshake blocks T cells from attacking the tumor. The first drugs that prevent the handshake, such as Bristol-Myers Squibb’s nivolumab and Merck’s pembrolizumab, target PD-1. Tecentriq binds with PD-L1, preventing the T-cell-sidelining handshake.

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For all the attention immunotherapies have received, especially for apparently curing what had previously been always-fatal melanoma, they help only a minority of patients. That was clear from the “IMpassion 130” clinical trial of Tecentriq for breast cancer, published last year. There, 451 patients received either Tecentriq plus the chemotherapy paclitaxel (Celgene’s Abraxane) or a placebo plus paclitaxel. The Tecentriq group had a median progression-free survival (the time before their disease spread or otherwise worsened, including fatally) of 7.2 months. The paclitaxel-alone group had a median PFS of 5.5 months.

In the patients whose tumors had PD-L1 molecules and who’d be expected to benefit more than those who don’t, median progression-free survival was 7.4 months, or only a week more than all of the Tecentriq patients. PD-L1 patients who received paclitaxel alone had median progression free survival of 4.8 months. There are not enough data to determine whether Tecentriq caused patients to live longer.

Data on overall survival aren’t final, but at last report the Tecentriq patients with PD-L1-positive tumors had a median overall survival of 25 months, compared to 15.5 months for chemo-only patients. “We expect the final survival analysis this year,” said medical oncologist and breast cancer specialist Dr. Hope Rugo of the University of California, San Francisco, an investigator on the IMpassion trial. “But we’ve never seen anything that changes survival like that in triple-negative patients.”

She also suspects that, as with melanoma patients who receive checkpoint inhibitors, some triple-negative breast cancer patients will not benefit from Tecentriq, but some will be cured.

Although the FDA approval was based on progression-free survival and on the fact that patients with triple-negative breast cancer have essentially no options, continued approval for triple-negative breast cancer “may be contingent upon verification and description of clinical benefit in a confirmatory trial(s),” Genentech, the Roche division that developed Tecentriq, said in a statement.

As is true of most immunotherapies, Tecentriq came with immune-system-related side effects, with more than 20 percent of patients suffering hair loss, tingling or numbness in the hands and feet, nausea, diarrhea, low red blood cells, constipation, or low white blood cells.

The American Cancer Society projects that about 40,000 people in the U.S. will be diagnosed with triple-negative breast cancer in 2019.

Sharon Begley

Senior Writer, Science and Discovery

Sharon covers science and discovery.

Published at Fri, 08 Mar 2019 23:09:44 +0000