MaaT Pharma has published retrospective real-world data from its CHRONOS study in the journal Bone Marrow Transplantation, providing outcomes for patients with third-line gastrointestinal acute graft-versus-host disease (GI-aGvHD).

The study analysed 59 patients across 16 European transplant centres who had steroid- and ruxolitinib-refractory disease and received a range of third-line treatment approaches excluding microbiome-based therapy.

CHRONOS is one of the largest contemporary real-world datasets describing outcomes in this heavily pretreated patient population, which is associated with poor prognosis and limited treatment options.

The study reported a day-28 gastrointestinal overall response rate of 37%, with 22% achieving complete response, and an all-organ response rate of 36%.

By day 56, response rates declined to 22% for gastrointestinal disease and 20% for all-organ response, indicating a reduction in durability of effect across available therapies.

Twelve-month overall survival was 29%, with a median overall survival of 86 days reported across the cohort.

Johannes Clausen, lead author of the study, said: “CHRONOS provides a contemporary reference point for third-line GI-aGvHD, underscoring both the gravity of this condition and the persistent lack of standardised, effective therapies.”

He added that the findings highlight the limited durability of response with currently available off-label treatment options in this high-risk population.

Most patients included in the analysis had severe disease, with a high proportion classified as grade III or IV aGvHD and resistance to both corticosteroids and ruxolitinib.

The most frequently used third-line therapies included anti-TNF agents, extracorporeal photopheresis and vedolizumab, reflecting heterogeneity in treatment approaches across centres.

The CHRONOS findings were also presented at the European Society for Blood and Marrow Transplantation annual congress and are being used to contextualise outcomes from MaaT Pharma’s ARES trial of MaaT013 (Xervyteg).

The company said the dataset provides a contemporary benchmark for outcomes in patients progressing beyond standard second-line therapy and supports interpretation of ongoing regulatory submissions in Europe.

Florent Malard, investigator on the ARES trial, said: “Acute GvHD remains a devastating disease with a profound unmet medical need.”

He added that CHRONOS offers important context for interpreting results from investigational therapies being evaluated in this setting.

The CHRONOS study forms part of a broader effort to better characterise real-world outcomes in acute GvHD following failure of established therapies, where treatment standards remain variable and outcomes are poor.