Keytruda Improves in Complete Response Rate in High-Risk Breast Cancer

Presurgical Keytruda plus chemotherapy improved outcomes for patients with high-risk, early-stage ER-positive, HER2-negative breast cancer, trial results showed.

The use of Keytruda (pembrolizumab) combined with chemotherapy before surgery may enhance pathological complete response (pCR) rates (the vacancy of invasive cancer cells within the breast/lymph nodes following the end of neoadjuvant therapy) compared with neoadjuvant placebo plus chemotherapy for patients with high-risk, early-stage breast cancer, according to findings from the phase 3 KEYNOTE-756 trial, announced by Merck, the manufacturer of Keytruda.

“This is the first positive phase 3 study evaluating an immunotherapy-based regimen for patients with high-risk, early-stage ER-positive, HER2-negative breast cancer, and an important milestone in our efforts to advance research in early-stage breast cancer,” Dr. Gursel Aktan, vice president, global clinical development at Merck Research Laboratories, said in a press release issued by Merck.

Medical professionals are looking into the cancer to find proper treatments, as breast cancer affects millions of individuals each year.

“Worldwide, more than two million people are diagnosed with breast cancer each year, and it is critically important that breast cancer is found and treated early, especially for patients with high-risk disease. While we wait for event-free survival data, these initial pCR results provide a potentially encouraging signal and may have important therapeutic implications for patients with high-risk, early-stage ER-positive, HER2-negative breast cancer,” explained Dr. Aditya Bardia, attending physician, medical oncology, Massachusetts General Hospital, director, breast cancer research, Massachusetts General Cancer Center, Associate professor, Harvard Medical School and co-principal investigator, in the release.

Patients with triple-negative breast cancer may now benefit from Keytruda, as it has been approved for two indications for this patient population. Patients can also benefit from Keytruda after surgery, by its continuation as a single agent, based on results from the trial and KEYNOTE- 522.

An FDA-approved test is also available Keytruda combined with chemotherapy for patients with locally recurrent unresectable or metastatic triple-negative breast cancer through advances from KEYNOTE-355, according to Merck.

Both KEYNOTE-355 and KEYNOTE-522s’ trials led to the approval of Keytruda-based regimens.

The final results of KEYNOTE-756 are yet to be announced and will be revealed shortly in a forthcoming medical meeting.

"We look forward to sharing the detailed results with the medical community and thank the patients and investigators for their important contributions to this study,” Aktan said.

The phase 3 study has become the first successful trial with an immunotherapy regimen to see improvements in pCR rates before main treatment takes place. Merck plans to continue the trial to investigate the endpoint of event-free survival (the extent of time to which a patient no longer has cancer/ the cancer worsens).

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