Merck has unveiled positive results from the Phase 3 KEYNOTE-355 trial, which evaluated KEYTRUDA in combination with chemotherapy as a treatment for metastatic triple-negative breast cancer (mTNBC).

KEYTRUDA is a humanised monoclonal antibody designed to block the interaction between PD-1 and its ligands, PD-L1 and PD-L2, to activate the T lymphocytes which may affect both tumour cells and healthy cells. The drug will improve the body’s immune system to detect and fight the tumour cells.

Merck Research Laboratories senior vice president and global clinical development head Roy Baynes said: “The progression-free survival results observed in KEYNOTE-355 have the potential to impart real change for certain patients with metastatic triple-negative breast cancer in the first-line setting.

“Merck is committed to evaluating innovative treatment approaches, anchored by KEYTRUDA, across multiple settings and stages of breast cancer.

“We are encouraged by the positive results from the Phase 3 KEYNOTE-355 and neoadjuvant/adjuvant KEYNOTE-522 studies, which demonstrate the potential of KEYTRUDA in combination with chemotherapy for the treatment of triple-negative breast cancer.”

KEYNOTE-355 is a Phase 3 clinical trial evaluating KEYTRUDA plus chemotherapy

Merck has been carrying out an immuno-oncology clinical research programme, under which more than 1,200 trials are studying KEYTRUDA across a broad range of cancers and treatment settings.

KEYNOTE-355 is a randomised, double-blinded, Phase 3 clinical trial evaluating KEYTRUDA in combination with chemotherapy compared with placebo plus chemotherapy to treat locally recurrent inoperable or mTNBC that has not been previously treated with chemotherapy.

Progression-free survival (PFS) and overall survival (OS) include the dual primary endpoints of the study and the secondary endpoints include objective response rate (ORR), duration of response (DOR), disease control rate (DCR) and safety.

In the clinical trial, KEYTRUDA plus chemotherapy has demonstrated a statistically significant and clinically meaningful improvement in PFS, reducing the risk of disease progression or death compared to those received chemotherapy alone.

IOB Institute of Oncology breast cancer program head Javier Cortes said: “There is a significant need for treatment regimens that can help women with metastatic triple-negative breast cancer, an aggressive disease.

“The results of this study, demonstrate that if approved, KEYTRUDA in combination with chemotherapy may offer certain women a new option for first-line treatment.”