Merck’s Keytruda in combination with chemotherapy has achieved the primary endpoint of progression-free survival (PFS) as first-line treatment for metastatic triple-negative breast cancer (mTNBC) in the phase 3 KEYNOTE-355 trial.
Keytruda plus chemotherapy achieved one of its dual primary endpoints of PFS in patients with mTNBC whose tumours expressed PD-L1.
Keytruda, an anti-PD-1 therapy, works by blocking the ability of the body’s immune system to help identify and kill tumour cells.
It is a humanised monoclonal antibody that inhibits the interaction between PD-1 and its ligands, PD-L1 and PD-L2, helping to activate T lymphocytes that may affect both tumour cells and healthy cells.
The first-line treatment with Keytruda plus chemotherapy (nab-paclitaxel, paclitaxel or gemcitabine/carboplatin) showed a statistically significant and clinically meaningful improvement in PFS compared against chemotherapy alone in these patients in an interim analysis conducted by an independent Data Monitoring Committee (DMC).
The Keytruda breast cancer clinical development programme includes various internal and external collaborative studies.
KEYNOTE-355 is a randomised, two-part and phase 3 trial designed to assess Keytruda in combination with one of three different chemotherapies compared with placebo plus one of the three chemotherapy regimens to treat locally recurrent inoperable or mTNBC, which has not been earlier treated with chemotherapy in the metastatic setting.
The trial’s part one was open-label and assessed the safety and tolerability of Keytruda in combination with either nab-paclitaxel, paclitaxel or gemcitabine/carboplatin in 30 patients.
The part 2 was double-blinded, with dual primary endpoints of OS and PFS in all participants, as well as in participants whose tumours expressed PD-L1. In addition, the secondary endpoints comprise of objective response rate (ORR), duration of response (DOR), disease control rate (DCR) and safety.
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.
“We look forward to sharing these findings with the medical community at an upcoming congress and discussing them with the FDA and other regulatory authorities.”
In September 2019, Merck and Eisai have announced that the US Food and Drug Administration (FDA) has approved Keytruda (pembrolizumab) plus Lenvima (lenvatinib) to treat patients with certain types of endometrial carcinoma.