Ipilimumab and Nivolumab Show Promise in Treating Rare Desmoid Tumors

Key Insights

• A Phase II basket trial evaluated the efficacy of dual anti-CTLA-4 and anti-PD-1 blockade with ipilimumab and nivolumab in patients with desmoid tumors.
• The study reported an overall response rate of 18.8% and a clinical benefit rate of 62.5% among the treated patients.
• Median progression-free survival was 19.4 months, suggesting a potential new treatment option for individuals with desmoid tumors.

A recent Phase II trial has indicated that the combination of ipilimumab and nivolumab, dual anti-CTLA-4 and anti-PD-1 immune checkpoint inhibitors, may offer a new treatment avenue for patients with rare desmoid tumors. The study, which involved 16 patients with histologically confirmed desmoid tumors who had no other viable treatment options, demonstrated an overall response rate (ORR) of 18.8% and a clinical benefit rate (CBR) of 62.5%. These findings suggest a potential advancement in the treatment of this rare neoplasm.

Study Details and Findings

The trial included patients with a median age of 37 years (range 20-82) from various centers in the United States. All patients had desmoid tumors confirmed through histology and lacked alternative treatments that could improve overall survival (OS) or had contraindications to such treatments. The ORR was 18.8% (3 out of 16 patients), with three patients experiencing a partial response (PR) and seven showing evidence of tumor shrinkage. The median progression-free survival (PFS) was 19.4 months (95% CI 8.3 months-not reached).

Current Treatment Landscape and Unmet Needs

Desmoid tumors, originating from fibroblasts, are extremely rare. The current standard of care typically involves active surveillance, with surgery reserved for specific cases. Systemic therapy, including chemotherapy and tyrosine kinase inhibitors, is indicated for unresectable disease. This trial addresses the need for more effective treatments, particularly for patients who do not respond to existing therapies or are not candidates for surgery.

Implications and Future Directions

The results of this Phase II trial suggest that ipilimumab and nivolumab could be a valuable addition to the treatment options for desmoid tumors. While the ORR was modest, the CBR and PFS indicate a meaningful clinical benefit for a significant proportion of patients. Further research, including larger clinical trials, is warranted to confirm these findings and to better understand the long-term efficacy and safety of this treatment approach.