Merck (MSD) has reported positive results from the Phase III KEYNOTE-355 clinical trial of Keytruda and chemotherapy combination in patients with metastatic triple-negative breast cancer (mTNBC).
The randomised, two-part KEYNOTE-355 study compared Merck’s anti-PD-1 therapy in combination with nab-paclitaxel, paclitaxel or gemcitabine/carboplatin to placebo plus one of the three chemotherapies.
Participants had locally recurrent inoperable mTNBC not previously treated with chemotherapy in the metastatic setting.
The open-label part of the trial investigated the safety and tolerability of the drug combination in 30 subjects, while the second double-blinded part assessed overall survival and progression-free survival as the dual primary endpoints in a total of 847 patients.
In addition, the trial monitored the secondary endpoints of objective response rate, duration of response, disease control rate, and safety.
Data showed that the endpoint of progression-free survival was reached, with a statistically significant and clinically meaningful improvement in the measure versus chemotherapy alone.
Following interim analysis, an independent Data Monitoring Committee (DMC) recommended that the trial continue without changes.
Safety data showed a profile consistent with previous results, with no new safety signals.
Merck Research Laboratories president Dr Roger Perlmutter said: “Triple-negative breast cancer is an aggressive malignancy. It is very encouraging that Keytruda in combination with chemotherapy has now demonstrated positive results as both a first-line treatment in the metastatic setting with this trial, and as neoadjuvant therapy in the KEYNOTE-522 trial.”
The drug’s breast cancer clinical development programme involves multiple internal and external collaborative studies.
In July last year, Merck reported positive data from the Phase III KEYNOTE-522 trial of Keytruda plus chemotherapy in triple-negative breast cancer patients.