X-ray cancer immunotherapy Tecentriq (atezolizumab), a PD-L1 inhibitor, received 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 type of breast cancer.
The approval was, as usual, 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 that the tumor cells do not have estrogen receptors, progesterone receptors or HER2, all of which burn uncontrolled cell proliferation, but can be blocked with drugs such as Herceptin.)
For all the attention immunotherapies have received, especially to apparently cure what had previously been fatal melanoma, they only help a minority of patients. It was evident from the "IMpassion 130" clinical study of Tecentriq for breast cancer, published last year. 451 patients received either Tecentriq plus chemotherapaclitaxel (Celgen's Abraxane) or placebo plus paclitaxel. The Tecentriq group had a median progression-free survival (time before their disease spread or otherwise worsened, including fatal) by 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 are expected to benefit from more than those who did not, progression-free survival was 7.4 months, or only one week more than all Tecentriq patients. PD-L1 patients who received paclitaxel alone had median progressive free survival of 4.8 months. There is not enough data to determine if Tecentriq caused patients to live longer.
Survival data is not definitive, but ultimately Tecentriq patients with PD-L1 positive tumors reported an average total 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 at the IMpassion trial. "But we have never seen anything that changes survival like that in triple-negative patients."
She also suspects that some triple-negative breast cancer patients, such as with melanoma patients receiving control point inhibitors, will not benefit from Tecentriq, but some will be cured.
Although the FDA approval was based on progression-free survival and that patients with triple-negative breast cancer have no potential, continued triple-negative breast cancer approval "may be subject to verification and description of clinical benefit in a confirmatory attempts, "Genentech, the Roche division that developed Tecentriq, said in a statement.
As is the case with most immunotherapies, Tecentriq came with immune system-related side effects, with more than 20 percent of patients suffering from hair loss, tingling or numbness in the hands and feet, nausea, diarrhea, low red blood cells, constipation or low whites. blood cells.
Americ a cancer association project that around 40,000 people in the United States will be diagnosed with triple-negative breast cancer in 2019.