Merck's Keytruda Secures Dual Approvals in Japan for Breast and Colorectal Cancers

Compiled and translated by | Tom Li

Recently, MSD’s blockbuster oncology drug Keytruda (pembrolizumab) secured two additional regulatory approvals in Japan for breast cancer and colorectal cancer, bringing the total number of approved indications for the therapy in Japan to 15 across 9 tumor types.

According to reports, Japan's Pharmaceuticals and Medical Devices Agency (PMDA) has approved MSD's Keytruda for patients with unresectable or recurrent PD-L1-positive, hormone receptor-negative, and human epidermal growth factor receptor 2 (HER2)-negative breast cancer.

In the randomized, placebo-controlled phase 3 KEYNOTE-355 (NCT02819518) trial, compared with the placebo plus chemotherapy group, patients receiving Keytruda plus chemotherapy demonstrated a statistically significant 35% reduction in the risk of disease progression or death. Progression-free survival (PFS) demonstrated a statistically and clinically significant prolongation (9.7 months vs. 5.6 months), and overall survival (OS) showed statistically and clinically meaningful improvement. The trial results confirm that the Keytruda plus chemotherapy regimen provides significant therapeutic benefits for this patient population.

The second indication for MSD's Keytruda approved in Japan is colorectal cancer. The therapy is approved for the treatment of unresectable, advanced or recurrent microsatellite instability-high (MSI-H) colorectal cancer.

In the open-label, Phase 3 KEYNOTE-177 (NCT02563002) trial, 307 patients with MSI-H or dMMR unresectable or metastatic CRC were randomized. The trial results showed that first-line Keytruda monotherapy significantly reduced the risk of disease progression or death by 40% compared with chemotherapy, doubling progression-free survival (median PFS: 16.5 months vs. 8.2 months).

Keytruda is an anti-programmed death receptor-1 (PD-1) therapy that enhances the ability of the patient's immune system to detect and combat tumor cells. This therapy is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands PD-L1 and PD-L2, thereby activating T lymphocytes that may affect both tumor cells and healthy cells.

Reports indicate that so far this year, Keytruda has already generated over $8 billion in sales for MSD, and the therapy's revenue this year appears poised to significantly surpass last year's $14.4 billion. However, competition in the PD-1/PD-L1 inhibitor market remains highly intense. Key competitors to MSD's Keytruda include Bristol Myers Squibb's Opdivo (nivolumab), Roche's Tecentriq (atezolizumab), and AstraZeneca's Imfinzi (durvalumab), along with numerous investigational therapies that may receive regulatory approval in the future. Nevertheless, with the current $32 billion market projected to expand to an annual $120 billion by the end of 2027, the future market size for MSD's Keytruda remains highly substantial.

Reference: Merck’s Keytruda gains two more approvals in Japan