FDA Approves Keytruda/Chemo for Triple-Negative Breast Cancer

The Food and Drug Administration (FDA) approved Keytruda (pembrolizumab) plus chemotherapy (carboplatin and paclitaxel then doxorubicin or epirubicin and cyclophosphamide) for the treatment of patients with high-risk, early-stage triple-negative breast cancer (TNBC), according to Merck, the manufacturer of the immunotherapy agent.

Per the approval, the Keytruda/chemotherapy regimen should be given before breast cancer surgery (the neoadjuvant setting) and then the anti-PD-1 therapy should be given alone after surgery (the adjuvant setting).

“We are proud to offer a new treatment option for patients faced with this challenging cancer. This neoadjuvant and adjuvant combination with Keytruda is the first immunotherapy regimen to be approved in high-risk early-stage TNBC, marking a meaningful milestone for the breast cancer community,” Dr. Vicki Goodman, vice president of clinical research at Merck Research Laboratories, said in a press release.

The approval is based on findings from the KEYNOTE-522 clinical trial, which demonstrated that Keytruda plus chemotherapy before surgery and continued as a single agent after surgery significantly improved event-free survival (the time where patients survived and had no cancer-related progression) compared to just neoadjuvant chemotherapy. Additionally, trial results showed that the newly approved regimen resulted in a 37% decrease in the risk of disease progression before definitive surgery, local or distant recurrence, another cancer or any-cause death.

“Even when TNBC is diagnosed early, 30% to 40% of patients will suffer cancer recurrence after standard neoadjuvant chemotherapy and surgery,” Dr. Joyce O’Shaughnessy, chair of Breast Cancer Research ay Baylor University Medical Center, Texas Oncology, U.S. Oncology in Dallas, said in the release. “Therefore, there is a high unmet need for new treatment options. Today’s approval is very welcome news and has the potential to change the treatment paradigm by now including an immunotherapy as part of the regimen for patients with high-risk early-stage TNBC.”

The approval also marks a welcome new treatment option for subgroups of patients who are disproportionately affected by TNBC. “Triple-negative is a difficult-to-treat type of breast cancer that unfortunately is more common in the U.S. in younger women and in Black women,” Goodman said in the release.

In November 2020, Keytruda plus chemotherapy was granted an accelerated approval for patients who had locally recurrent or unresectable (not eligible for surgery) metastatic TNBC, whose tumors expressed PD-L1 – the biomarker that Keytruda inhibits, thus activating the immune system to attack the cancer. Now, the FDA converted the accelerated approval to a full approval.

Since Keytruda kickstarts the immune system to find and fight cancer cells, patients should be aware of the treatment’s immune-related side effects, which could be fatal and may include: pneumonitis, colitis, hepatitis, endocrinopathies (hormone problems), nephritis, dermatologic reactions, solid organ transplant rejection and complications of allogeneic hematopoietic stem cell transplantation. It is recommended that patients should talk to their health care team immediately if they experience any side effects from Keytruda, which can occur at any time during or after treatment.

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