Eisai & MSD submit the LENVIMA + WELIREG combination for RCC in Japan

JAPAN—Eisai Co., Ltd. and MSD K.K., a subsidiary of Merck & Co., Inc., have submitted an application in Japan to expand the approved use of LENVIMA® (lenvatinib), an oral tyrosine kinase inhibitor developed by Eisai.

The application seeks approval for LENVIMA in combination with WELIREG® (belzutifan), MSD’s first-in-class oral HIF-2α inhibitor, to treat patients with unresectable or metastatic renal cell carcinoma (RCC) whose disease has progressed following prior therapy.

Strong clinical results drive the application

The submission draws on findings from the Phase 3 LITESPARK-011 trial, which tested the LENVIMA plus WELIREG combination in patients with advanced RCC who had previously received anti-PD-1/PD-L1 immunotherapy.

Results from the trial were presented at the 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium in February 2026.

At a pre-specified interim analysis, with a median follow-up of 29 months, the combination reduced the risk of disease progression or death by 30% compared to cabozantinib.

No new safety concerns emerged, and the combination’s side effect profile remained consistent with what had been observed when each drug was used alone.

The burden of kidney cancer

The need for better treatment options is substantial.

In 2022, approximately 435,000 people worldwide received a new kidney cancer diagnosis, and around 156,000 died from it.

In Japan alone, roughly 21,000 new cases and 7,000 deaths were recorded that same year. RCC accounts for about 85% of all kidney cancers.

Five-year survival rates remain relatively low for advanced stages — between 63% and 78% for stage III, and just 27% to 28% for stage IV patients — highlighting the continued need for more effective therapies.

Current approvals and regulatory activity

LENVIMA already holds approval in Japan in combination with KEYTRUDA® (pembrolizumab) as a first-line treatment for unresectable or metastatic RCC.

WELIREG is also approved in Japan for RCC that has progressed after chemotherapy.

Separately, the U.S. Food and Drug Administration has accepted a supplemental New Drug Application for the LENVIMA and WELIREG combination in adults with advanced clear-cell RCC following prior PD-1 or PD-L1 therapy, with a PDUFA target action date of October 4, 2026.

Eisai and MSD have maintained a collaboration on LENVIMA in Japan since October 2018 and continue working jointly to expand access for patients with cancer.