HQ Team
July 29, 2023: Merck & Co., Inc., announced it has met one of the primary goals during a late-stage trial of its breast cancer therapy, Keytruda.
In the phase III trial, the therapy demonstrated a “statistically significant improvement” in pathological complete response (pCR) rate compared to neoadjuvant placebo plus chemotherapy.
A pCR is defined as a lack of all signs of cancer in the tissue samples analyzed following completion of neoadjuvant therapy and definitive surgery.
A neoadjuvant therapy refers to treatment, such as chemotherapy or hormone therapy, administered prior to the primary cancer treatment, such as surgery. In certain breast cancers, neoadjuvant therapies reduce recurrences by 50%.
Independent committee
Based on the recommendation of an independent Data Monitoring Committee, the trial will continue without changes to evaluate the other dual primary endpoint of event-free survival as per the trial design, according to Merck.
The safety profile of Keytruda in the late-stage trial was consistent with that observed in previously reported studies and no new safety signals were identified.
The investigation was the first positive phase III study evaluating an immunotherapy-based regimen for patients with high-risk, early-stage breast cancer, said Dr. Gursel Aktan, vice president, of global clinical development, Merck Research Laboratories.
“We look forward to sharing the detailed results with the medical community,” he said.
Breast cancer is one of the leading causes of cancer-related death in women worldwide, with more than two million patients diagnosed and approximately 685,000 deaths from the disease globally in 2020.
Types of breast cancer
In the U.S., it is estimated there will be about 298,000 patients diagnosed with breast cancer and 43,700 deaths from the disease in 2023.
The are many different types of breast cancer and various subtypes. Of all breast cancer patients, about 70% will be diagnosed with hormone receptor-positive, HER2-negative disease.
Cancer recurrence following surgery for this type of cancer is most common within five years, and patients with high-risk features have a greater chance of recurrence.
It is “critically important that breast cancer is found and treated early, especially for patients with high-risk disease,” said Dr. Aditya Bardia, attending physician, medical oncology, Massachusetts General Hospital.
“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.”
The trial enrolled 1,240 patients. There are currently more than 1,600 trials studying Keytruda across a wide variety of cancers and treatment settings, according to Merck.
