Tomostrocel (MSC-FFM) in multi-refractory aGvHD: A real-world analysis

Results from a retrospective analysis of prospectively collected surveillance data evaluating tomostrocel, a mesenchymal stromal cell (MSC) product, in adults with multi-refractory acute graft-versus-host disease (aGvHD; N = 317) treated at European transplant centers between 2017 and 2025 were published in Transplantation and Cellular Therapy by Verbeek et al. aGvHD was mostly severe (Grade 3, 37%; Grade 4, 55%) and the lower gastrointestinal (GI) tract was the predominant site of involvement. Patients had received a median of three prior lines of therapy (LoT), including ruxolitinib in 75% of cases, and were followed for 24 months from first administration of tomostrocel. Response rates, overall survival (OS), and adverse reactions were evaluated. 

Key data: At Day 28, the overall response rate (ORR) was 45% (95% confidence interval [CI], 40–51), including a complete response (CR) in 12% of patients. Median OS was 4.3 months, and OS at 6, 12, and 24 months was 44%, 33%, and 28%, respectively. Response and survival were comparable regardless of prior ruxolitinib exposure; Day 28 ORR was 47% in patients who had received ruxolitinib (n = 239) vs 39% in those who had not (n = 78), and 24-month OS was 29% vs 25%, respectively. Adverse drug reactions were reported in 1.6% of patients, including three serious infectious events.

Key learning: In this real-world analysis, tomostrocel demonstrated promising efficacy and a well-tolerated safety profile in heavily pretreated adults with multi-refractory aGvHD. Despite the inherent limitations of real-world data, these findings support further investigation of tomostrocel as a treatment option for this patient population, with further evaluation underway in two randomized controlled trials (NCT04629833, NCT06075706).