On March 27, 2026 Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, "Eisai") and MSD K.K. (Headquarters: Tokyo, Representative Director: Prashant Nikam, "MSD"), a subsidiary of Merck & Co., Inc., Rahway, NJ, USA, reported that an application for LENVIMA (lenvatinib), an orally available multiple receptor tyrosine kinase inhibitor (TKI) discovered by Eisai, has been submitted in Japan for the additional dosage and administration in combination with WELIREG (belzutifan), the first-in-class oral hypoxiainducible factor-2 alpha (HIF-2α) inhibitor from MSD, for the treatment of unresectable or metastatic renal cell carcinoma that has progressed after chemotherapy.
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This application is based on the results of the Phase 3 LITESPARK-011 trial evaluating the dual regimen of LENVIMA plus WELIREG for the treatment of patients with advanced renal cell carcinoma (RCC) whose disease progressed on or after treatment with anti-programmed death receptor-1 (PD-1)/ programmed death-ligand 1 (PD-L1) therapy. The data from this trial were presented at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Genitourinary (GU) Cancers Symposium in February 2026. At a pre-specified interim analysis with a median follow-up of 29.0 months (range, 19.3-49.2), the LENVIMA plus WELIREG combination therapy demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS), one of the primary endpoints, reducing the risk of disease progression or death by 30% (HR=0.70 [95% CI, 0.59-0.84]; p=0.00007) compared to cabozantinib. The safety profile of this combination was consistent with those reported for each agent administered as monotherapy, and no new safety signals were identified.
In 2022, approximately 435,000 people worldwide were newly diagnosed with kidney cancer, and about 156,000 people died from the disease. 1 In Japan, it is estimated that roughly 21,000 people were newly diagnosed and about 7,000 died in 2022.2 RCC accounts for approximately 85% of kidney cancers3, and the five-year survival rates for patients with stage III and IV RCC have been reported as 63%–78% and 27%–28%4, respectively, indicating that the disease still has a high unmet medical needs.
LENVIMA is approved in combination with KEYTRUDA (pembrolizumab) in Japan for the first-line treatment of unresectable or metastatic RCC. WELIREG is approved in Japan for the treatment of unresectable or metastatic RCC that has progressed following cancer chemotherapy. Additionally, supplemental New Drug Applications (sNDA) for the LENVIMA and WELIREG combination therapy for the treatment of adult patients with advanced RCC with a clear cell component following a PD-1 or PDL1 inhibitor has been accepted by the U.S. Food and Drug Administration (FDA), with a PDUFA (Prescription Drug User Fee Act) target action date set for October 4, 2026.
Eisai and MSD have been collaborating through the provision of information on LENVIMA in Japan since October 2018, and will work together to expedite the maximization of contribution to patients with cancer.
About LENVIMA (lenvatinib)
LENVIMA, discovered and developed by Eisai, is an orally available multiple receptor tyrosine kinase inhibitor that inhibits the kinase activities of vascular endothelial growth factor (VEGF) receptors VEGFR1 (FLT1), VEGFR2 (KDR), and VEGFR3 (FLT4). LENVIMA inhibits other kinases that have been implicated in pathogenic angiogenesis, tumor growth, and cancer progression in addition to their normal cellular functions, including fibroblast growth factor (FGF) receptors FGFR1- 4, the platelet derived growth factor receptor alpha (PDGFRα), KIT, and RET. In syngeneic mouse tumor models, LENVIMA decreased tumor-associated macrophages, increased activated cytotoxic T cells, and demonstrated greater antitumor activity in combination with an anti-PD-1 monoclonal antibody compared to either treatment alone. LENVIMA has been approved for the indications below.
Thyroid cancer
– Indication as monotherapy
(Approved mainly in Japan, the United States, Europe, China and Asia)
Japan: Unresectable thyroid cancer
The United States: The treatment of patients with locally recurrent or metastatic, progressive, radioiodine-refractory differentiated thyroid cancer (DTC)
Europe: The treatment of adult patients with progressive, locally advanced or metastatic, differentiated (papillary/follicular/Hürthle cell) thyroid carcinoma (DTC), refractory to radioactive iodine (RAI)
Hepatocellular carcinoma
– Indication as monotherapy
(Approved mainly in Japan, the United States, Europe, China and Asia)
Japan: Unresectable hepatocellular carcinoma
The United States: The first-line treatment of patients with unresectable hepatocellular carcinoma (HCC)
Europe: The treatment of adult patients with advanced or unresectable hepatocellular carcinoma (HCC) who have received no prior systemic therapy
– Indication in combination with KEYTRUDA (generic name: pembrolizumab) and transarterial chemoembolization (Approved in China)
Thymic carcinoma
– Indication as monotherapy (Approved in Japan)
Japan: Unresectable thymic carcinoma
Renal cell carcinoma (In Europe other than the United Kingdom, the agent was launched under the brand name Kisplyx)
– Indication in combination with everolimus
(Approved mainly in the United States, Europe and Asia) The United States: The treatment of adult patients with advanced renal cell carcinoma (RCC) following one prior anti-angiogenic therapy
Europe: The treatment of adult patients with advanced renal cell carcinoma following one prior vascular endothelial growth factor (VEGF) targeted therapy
– Indication in combination with KEYTRUDA
(Approved mainly in Japan, the United States, Europe and Asia)
Japan: Radically unresectable or metastatic renal cell carcinoma
The United States: The first-line treatment of adult patients with advanced renal cell carcinoma
Europe: The first-line treatment of adult patients with advanced renal cell carcinoma
Endometrial carcinoma
– Indication in combination with KEYTRUDA
(Approved mainly in Japan, the United States, Europe and Asia)
Japan: Unresectable, advanced or recurrent endometrial carcinoma that progressed after cancer chemotherapy
The United States: The treatment of patients with advanced endometrial carcinoma that is pMMR or not microsatellite instability-high (MSI-H), as determined by an FDA-approved test, who have disease progression following prior systemic therapy in any setting and are not candidates for curative surgery or radiation
Europe: The treatment of adult patients with advanced or recurrent endometrial carcinoma (EC) who have disease progression on or following prior treatment with a platinum-containing therapy in any setting and are not candidates for curative surgery.
About WELIREG (belzutifan)
WELIREG, Merck & Co., Inc., Rahway, NJ, USA’s, known as MSD outside of the United States and Canada, first-in-class hypoxia-inducible factor 2 alpha (HIF-2α) inhibitor, is an orally administered small-molecule designed to reduce transcription and expression of HIF-2α target genes associated with cellular proliferation, angiogenesis and tumor growth. By inhibiting HIF-2α signaling, WELIREG aims to disrupt key pathways certain tumors may use to adapt to low-oxygen conditions, including those that help promote abnormal blood vessel formation and support tumor survival. WELIREG has demonstrated antitumor activity in certain von Hippel-Lindau (VHL) diseaseassociated tumors, renal cell carcinoma and in pheochromocytoma or paraganglioma. As part of a broader clinical program, Merck & Co., Inc., Rahway, NJ, USA continues to research WELIREG monotherapy and combination approaches for people with genitourinary, breast and gynecologic cancers across a range of treatment settings to further define where HIF-2α inhibition may provide clinical benefit and to better understand which patients are most likely to respond. WELIREG has been approved in Japan for the treatment of certain von Hippel–Lindau (VHL) disease–associated tumors, as well as for unresectable or metastatic renal cell carcinoma that has progressed after chemotherapy.
LITESPARK-011 Results
Data from LITESPARK-011 (ClinicalTrials.gov, NCT04586231) were presented at the ASCO (Free ASCO Whitepaper) GU Symposium held in February 2026. LITESPARK-011 is a randomized, open-label Phase 3 trial (ClinicalTrials.gov, NCT04586231) evaluating WELIREG in combination with LENVIMA compared to cabozantinib for the treatment of patients with advanced clear cell RCC that has progressed on or after anti-PD-1/L1 therapy. The dual primary endpoints are progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) as assessed by blinded independent central review (BICR), and overall survival (OS). Secondary endpoints include objective response rate (ORR) per RECIST v1.1 as assessed by BICR, duration of response (DOR) per RECIST v1.1 as assessed by BICR, and safety. The trial enrolled 747 patients who were randomized to receive WELIREG (120 mg orally once daily) plus LENVIMA (20 mg orally once daily) or cabozantinib (60 mg orally once daily).
At a pre-specified second interim analysis with a median follow-up of 29.0 months (range, 19.3- 49.2), WELIREG plus LENVIMA demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of PFS, reducing the risk of disease progression or death by 30% (HR=0.70 [95% CI, 0.59-0.84]; p=0.00007) compared to cabozantinib. For WELIREG plus LENVIMA, the median PFS was 14.8 months (95% CI, 11.2-16.6) versus 10.7 months (95% CI, 9.2-11.1) for cabozantinib. A trend toward improvement in overall survival (OS), the trial’s other primary endpoint, was also observed for WELIREG plus LENVIMA (HR=0.85 [95% CI, 0.68-1.05]; p=0.06075). The median OS was 34.9 months (95% CI, 27.5-NR) for WELIREG plus LENVIMA versus 27.6 months (95% CI, 24.0-31.4) for cabozantinib. The trial is continuing, and OS will be evaluated at a subsequent analysis per the clinical trial protocol. Regarding secondary endpoints, at the first interim analysis with a median follow-up of 19.6 months (range, 9.9-39.8), WELIREG plus LENVIMA met ORR, demonstrating a statistically significant improvement compared to cabozantinib. A confirmed ORR of 52.6% (95% CI, 47.3-57.7) was observed for WELIREG plus LENVIMA versus 39.6% (95% CI, 34.6-44.8) for cabozantinib. At the second interim analysis with a median follow-up of 29.0 months, the median DOR was 23.0 months (95% CI, 2.0-44.3+) for WELIREG plus LENVIMA versus 12.3 months (95% CI, 1.8+-35.9+) for cabozantinib. WELIREG plus LENVIMA was administered to 370 patients and cabozantinib was administered to 371 patients. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 71.6% of patients receiving WELIREG plus LENVIMA versus 65.8% of patients receiving cabozantinib. Adverse events led to treatment discontinuation in 11.1% of patients receiving WELIREG plus LENVIMA and in 11.3% of patients receiving cabozantinib, respectively. Serious adverse events were observed in 51.6% of patients receiving WELIREG plus LENVIMA versus 43.9% of patients receiving cabozantinib, and AEs led to death in 5.4% of patients (two were treatment-related: thrombotic microangiopathy [n=1] and pneumonitis [n=1]) versus 3.2% (one was treatment-related: hemoptysis [n=1]) of patients, respectively.
(Press release, Eisai, MAR 27, 2026, View Source [SID1234663976])