Results show that adding Welireg (belzutifan) to Keytruda after surgery significantly lowers the risk of cancer coming back in patients with clear cell renal cell carcinoma.
The study found that the combination reduced the risk of recurrence or death by 28% compared with Keytruda alone. After 24 months, 81% of patients who received both drugs were cancer-free, compared with 74% of those who received only Keytruda. This is the first phase 3 trial to show that a drug combination works better than Keytruda alone as post-surgery treatment for this type of kidney cancer.
However, the combination caused more side effects. Common problems included fatigue, nausea, and joint pain. Patients taking Welireg had much higher rates of anemia (84% compared with 12%) and low oxygen levels (7%). Serious side effects were also more common with the combination (52% versus 30%), but researchers said most side effects could be managed, and only a small number of patients stopped treatment completely.
Although the results clearly show better disease-free survival, it is still too early to know whether the combination helps patients live longer. Longer follow-up is needed, but the findings suggest the treatment could become a new standard option for patients at high risk of kidney cancer returning.