MSD has revealed that its cancer blockbuster Keytruda (pembrolizumab) significantly prolonged progression-free survival (PFS) when added to chemo in a triple-negative breast cancer trial.

In the Phase III KEYNOTE-355 trial, the drug was compared in combination with one of three different chemotherapies, to placebo plus one of the three chemotherapy regimens, in patients with locally recurrent, inoperable or metastatic triple-negative breast cancer.

Roger Perlmutter, president of MSD Research Laboratories said that it is “very encouraging” that the drug 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 company reminds that in addition to KEYNOTE-355 and KEYNOTE-522, Keytruda is also being evaluated in the same indication in the ongoing KEYNOTE-242 trial.

Last year, Roche's Tecentriq (atezolizumab), in combination with chemotherapy, became the first immunotherapy regimen to be approved in breast cancer.

Earlier this week, The National Institute for Health and Care Excellence (NICE) released a draft guidance rejecting Keytruda when used in combo with Pfizer’s Inlyta (axitinib) to treat advanced renal cell carcinoma (RCC).

NICE already routinely commissions various drugs for first-line treatment of RCC, including Aveo’s Fotivda (tivozanib), Pfizer’s Sutent (sunitinib) and an Opdivo (nivolumab) Yervoy (ipilimumab) combination - the latter being through the Cancer Drugs Fund.

Triple-negative breast cancer is cancer that tests negative for estrogen receptors, progesterone receptors, and excess HER2 protein. These results mean the growth of the cancer is not fuelled by the hormones estrogen and progesterone, or by the HER2 protein.