Monitoring Sarcoma Response to Immune Checkpoint Inhibition and Local Cryotherapy with Circulating Tumor DNA Analysis.

PURPOSE: Immune checkpoint inhibition has led to promising responses in soft tissue sarcomas (STS), but the majority of patients do not respond and biomarkers of response will be crucial. Local ablative therapies may augment systemic responses to immunotherapy. We evaluated circulating tumor DNA (ctDNA) as a biomarker of response in patients treated on a trial combining immunotherapy with local cryotherapy for advanced STS. PATIENTS AND METHODS: We enrolled 30 patients with unresectable or metastatic STS to a phase II clinical trial. Patients received ipilimumab and nivolumab for four doses followed by nivolumab alone with cryoablation performed between cycles 1 and 2. The primary endpoint was objective response rate (ORR) by 14 weeks. Personalized ctDNA analysis using bespoke panels was performed on blood samples collected prior to each immunotherapy cycle. RESULTS: ctDNA was detected in at least one sample for 96% of patients. Pretreatment ctDNA allele fraction was negatively associated with treatment response, progression-free survival (PFS), and overall survival (OS). ctDNA increased in 90% of patients from pretreatment to postcryotherapy, and patients with a subsequent decrease in ctDNA or undetectable ctDNA after cryotherapy had significantly better PFS. Of the 27 evaluable patients, the ORR was 4% by RECIST and 11% by irRECIST. Median PFS and OS were 2.7 and 12.0 months, respectively. No new safety signals were observed. CONCLUSIONS: ctDNA represents a promising biomarker for monitoring response to treatment in patients with advanced STS, warranting future prospective studies. Combining cryotherapy and immune checkpoint inhibitors did not increase the response rate of STS to immunotherapy.

Long-Term Remission with Ipilimumab/Nivolumab in Two Patients with Different Soft Tissue Sarcoma Subtypes and No PD-L1 Expression.

Checkpoint inhibitor therapy has been shown to improve outcomes in multiple solid malignancies; however, data are limited in soft tissue sarcoma. We present two cases of patients with advanced soft tissue sarcoma of different subtypes (dedifferentiated liposarcoma and myxofibrosarcoma) with zero percent PD-L1 expression by immunohistochemistry who were treated with ipilimumab and nivolumab followed by maintenance nivolumab. Both patients had failed multiple lines of systemic treatment and experienced long-term remission after starting ipilimumab and nivolumab. Genetic testing revealed that no genetic mutations were found in common between the two cases. One patient received concurrent cryoablation, which may have sensitized his tumor to immunotherapy. Checkpoint inhibitor therapy may improve outcomes in soft tissue sarcoma regardless of PD-L1 status, especially when combined with cryoablation. Studies are needed to evaluate whether treatment response varies by sarcoma subtype and what molecular markers can be used to guide patient selection.

Nivolumab plus ipilimumab for soft tissue sarcoma: a single institution retrospective review.

Aim: To analyze the efficacy of checkpoint inhibitors in soft tissue sarcoma. Materials & methods: We retrospectively reviewed patients with advanced soft tissue sarcoma treated with ipilimumab and nivolumab. All patients who received at least one cycle were included. Results: One patient had a complete response and five had a partial response, for an objective response rate of 15%. Clinical benefit rate was 34% with a median duration of 12.0 months (range: 4.5 to 28.9+ months [mo]). Median overall survival was 12.0 months (95% CI: 4.5-23.7+ mo). Median progression-free survival was 2.7 months (95% CI: 2.3-4.5+ mo) by Response Evaluation Criteria in Solid Tumors 1.1 and 2.9 months (2.5-6.0+ mo) by immune-related Response Evaluation Criteria in Solid Tumors. Adverse events of any grade were seen in 58% of patients, the most common being fatigue (21%) and cough (10%), 5% of patients experienced a grade 3 adverse event (AE) (hyperglycemia) or grade 4 AE (myocarditis). Conclusion: Ipilimumab/nivolumab combination showed efficacy and was well tolerated in advanced soft tissue sarcoma.