On June 12, 2026, the U.S. Food and Drug Administration (FDA) approved belzutifan (Welireg, Merck & Co., Inc.) in combination with pembrolizumab (Keytruda) or pembrolizumab and berahyaluronidase alfa-pmph (Keytruda Qlex) for the adjuvant treatment of adults with renal cell carcinoma with a clear cell component (ccRCC) at intermediate-high or high risk of recurrence following nephrectomy, or following nephrectomy and resection of metastatic lesions. This marks a new combination strategy in the post-surgical management of high-risk ccRCC, adding a HIF-2α inhibitor to established checkpoint blockade.

Clinical Takeaway

The FDA approval of belzutifan plus pembrolizumab in the adjuvant ccRCC setting is supported by a statistically significant improvement in disease-free survival (DFS) from the LITESPARK-022 trial, representing the first approved combination of a HIF-2α inhibitor and a PD-1 checkpoint inhibitor in this context. The regimen targets patients at the highest risk of disease recurrence following definitive surgical management.

Drug Profile & Mechanism

  • Belzutifan (Welireg): A first-in-class oral hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor that blocks the HIF-2α/ARNT heterodimer, reducing transcription of downstream targets involved in tumor proliferation, angiogenesis, and survival — pathways commonly dysregulated in ccRCC due to VHL loss.
  • Pembrolizumab (Keytruda): A humanized anti-PD-1 monoclonal antibody that restores anti-tumor T-cell immunity by blocking the PD-1/PD-L1 interaction.
  • Pembrolizumab and berahyaluronidase alfa-pmph (Keytruda Qlex): A subcutaneous coformulation of pembrolizumab with a recombinant hyaluronidase, offering an alternative to intravenous administration.

Target Population

  • Indication: Adult patients with renal cell carcinoma with a clear cell component (ccRCC)
  • Risk criteria: Intermediate-high or high risk of recurrence following nephrectomy, or following nephrectomy and resection of metastatic lesions
  • Setting: Adjuvant (post-surgical, no evidence of disease)

Study Design: LITESPARK-022

  • Trial: LITESPARK-022 (NCT05239728)
  • Design: Multicenter, double-blind, randomized controlled trial
  • Enrollment: 1,841 patients with prior nephrectomy for ccRCC who were at intermediate-high or high risk of recurrence, or who had resected metastases with no evidence of disease
  • Randomization: 1:1 to belzutifan plus pembrolizumab (experimental arm) or placebo plus pembrolizumab (control arm)
  • Treatment duration:
    • Belzutifan or placebo: up to 54 weeks
    • Pembrolizumab: up to 12 months
    • Treatment continued until disease recurrence or unacceptable toxicity

Endpoints

  • Primary endpoint: Investigator-assessed disease-free survival (DFS), defined as time from randomization to recurrence, metastasis, or death
  • Key secondary endpoint: Overall survival (OS) — data not yet mature at the time of the prespecified interim analysis

Efficacy Outcomes

  • At a prespecified interim analysis, belzutifan plus pembrolizumab demonstrated a statistically significant improvement in DFS versus placebo plus pembrolizumab
  • Events: 186 events in the belzutifan plus pembrolizumab arm vs. 246 events in the placebo plus pembrolizumab arm
  • Hazard ratio (HR): 0.72 (95% CI: 0.59–0.87)
  • P-value: 0.0003
  • Median DFS: Not reached in either arm
  • Overall survival: Data were not mature at the protocol-specified interim analysis

Safety

Clinicians should be aware of the distinct safety profiles of each agent in the combination regimen:

  • Belzutifan (Welireg) — Boxed Warning:
    • Embryo-fetal toxicity
  • Belzutifan — Warnings and Precautions:
    • Anemia
    • Hypoxia
  • Pembrolizumab (Keytruda / Keytruda Qlex) — Warnings and Precautions:
    • Immune-mediated adverse reactions
    • Infusion-related reactions
    • Complications of allogeneic hematopoietic stem cell transplantation
    • Embryo-fetal toxicity

Healthcare professionals should refer to the full prescribing information for Welireg, Keytruda, and Keytruda Qlex on Drugs@FDA for complete safety and monitoring guidance. All serious adverse events should be reported to FDA MedWatch at 1-800-FDA-1088.

Recommended Dosage

  • Belzutifan: 120 mg orally once daily until disease recurrence, unacceptable toxicity, or for up to 54 weeks
  • Pembrolizumab (IV):
    • 200 mg intravenously every 3 weeks, or
    • 400 mg intravenously every 6 weeks
    • In combination with belzutifan 120 mg orally once daily until disease recurrence, unacceptable toxicity, or for up to 12 months
  • Pembrolizumab and berahyaluronidase alfa-pmph (SC):
    • 395 mg/4,800 units subcutaneously every 3 weeks, or
    • 790 mg/9,600 units subcutaneously every 6 weeks
    • In combination with belzutifan 120 mg orally once daily until disease recurrence, unacceptable toxicity, or for up to 12 months

Key Clinical Implications

✔ Belzutifan plus pembrolizumab is now an FDA-approved adjuvant option for adults with intermediate-high or high-risk ccRCC following nephrectomy, or following nephrectomy and resection of metastatic lesions, providing clinicians a novel combination strategy in this high-risk surgical population.

✔ The 28% relative reduction in the risk of recurrence, metastasis, or death (HR 0.72; p=0.0003) observed in LITESPARK-022 supports meaningful clinical benefit, though median DFS was not reached in either arm, and overall survival data remain immature.

✔ The availability of a subcutaneous pembrolizumab coformulation (Keytruda Qlex) alongside IV pembrolizumab offers scheduling and administration flexibility for patients and oncology practices.

✔ Clinicians should counsel patients — particularly women of reproductive potential — about the embryo-fetal toxicity warnings associated with both belzutifan and pembrolizumab, and monitor for belzutifan-specific toxicities, including anemia and hypoxia throughout the treatment course.

✔ This approval was granted Priority Review and reviewed under Project Orbis with the Australian Therapeutic Goods Administration (TGA) and Health Canada; regulatory reviews at those agencies are ongoing, signaling broader international interest in this regimen.

Bottom Line

The FDA approval of belzutifan plus pembrolizumab represents a significant advance in the adjuvant management of high-risk ccRCC, combining HIF-2α inhibition with checkpoint blockade for the first time in the post-nephrectomy setting. With a statistically significant DFS benefit (HR 0.72; p=0.0003) demonstrated in a large, randomized, double-blind trial of 1,841 patients, this regimen offers a new evidence-based option for patients at the greatest risk of recurrence. Oncology clinicians should familiarize themselves with the distinct safety profiles of each component, particularly anemia, hypoxia, and immune-mediated adverse events, to optimize patient selection and toxicity management. Longer-term follow-up for overall survival maturation will be important for fully characterizing the clinical benefit of this combination.

Sources:

  • U.S. Food and Drug Administration. (2026). FDA approves belzutifan plus pembrolizumab for adjuvant treatment of renal cell carcinoma. FDA Oncology Center of Excellence — Resources and Information on Approved Drugs. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-belzutifan-pembrolizumab-adjuvant-treatment-renal-cell-carcinoma