Symposium | The importance of real-world data in allogeneic stem cell transplantation: A focus on cGvHD

The GvHD Hub held a virtual symposium on October 21, 2025, titled, Guidance vs practice: How can we improve treatment of steroid-refractory graft-versus-host disease (SR-GvHD)? Here, we share a presentation by Mohamad Mohty, Sorbonne University Hôpital Saint-Antoine, Paris, FR, discussing the importance of real-world data (RWD) in allogeneic stem cell transplantation with a focus on chronic GvHD (cGvHD).

Mohty provided an overview of RWD, discussing their role in regulatory decision-making, the various types of RWD, study designs, and limitations. Mohty explored whether pivotal clinical trial results can be reproduced with RWD, highlighting the consistent outcomes observed in a French compassionate use program of belumosudil. Mohty concluded the session by providing a patient case focusing on treatment selection in SR-GvHD.

Key points

• RWD are data relating to patient health status and/or healthcare delivery, which are routinely collected from a variety of sources. Real-world evidence (RWE) is clinical evidence on the use and potential benefits of a medical product, derived from analysis of RWD.¹
• RWD/RWE are clinically relevant for physicians and payers; they can allow for hypothesis generation, comparative effectiveness, treatment strategy assessments, quality of care, and effectiveness.^2,3
• In regulatory decision-making, RWD/RWE can enable analysis of real-world drug use patterns, post-authorization safety studies, detection of drug–drug interactions, and economic modeling.^2–5
  • They can also assess alternative dosing regimens for established medicines, identify target–drug combinations for randomized controlled trials, and support label expansion.^2,3,6
• Numerous types of RWD can be collected across many settings (Figure 1), which can be merged or aggregated, and collected longitudinally.^3,7

• For selecting an appropriate data source for RWD/RWE, various strengths and limitations can be considered (Table 1).

• RWD/RWD study designs include pragmatic clinical trials, prospective and retrospective observational studies, externally controlled trials, and descriptive studies.^3,9,10
• Limitations of RWD/RWE include missing data or availability of key data, completeness of available variables, lack of randomization and written protocols, and lack of monitoring and control over the quality of data collection.^3,11,12
• RWD can enhance understanding of approved drugs and reproduce clinical trial outcomes in real-world settings, strengthening confidence in their clinical use.
• Belumosudil, a Rho-associated protein kinase 2 inhibitor, was evaluated in the multicenter, phase II ROCKstar trial (NCT03640481) in patients with cGvHD who had received 2–5 prior lines of therapy. The best overall response rate (ORR; primary endpoint) at 1 year was 74% and 77% for the 200 mg once daily (n = 66) and 200 mg twice daily (n = 66) dose arms, respectively.¹³
  • The 3-year follow-up of the ROCKstar study demonstrated consistent efficacy and tolerability of belumosudil (Figure 2).^14,15

• In a French compassionate use program, 68 patients with cGvHD received belumosudil, the majority (94%) of whom had moderate–severe cGvHD and a median (range) of 3 (2–8) treatment lines prior to belumosudil at onset.¹⁶
• After a median follow-up of 337 days, belumosudil responses were observed at 3 and 6 months, with 57% of patients experiencing a complete response (CR) or partial response (PR) as their best response (Figure 3).¹⁶

• Overall survival rates at 6 and 12 months were 89.1% and 84.7%, respectively. Failure-free survival rates at 6 and 12 months were 89.1% and 80.4%, respectively.¹⁶
• Nine patients died on treatment, predominantly from GvHD, and ten patients experienced AEs (Table 2).¹⁶

• Overall, results of this French compassionate use program of real-world belumosudil were comparable with previous clinical trials.¹⁶

Patient case study

• Mohty presented a patient case of a female aged 49 years with acute myeloid leukemia in first complete remission, who underwent a peripheral blood allogeneic hematopoietic stem cell transplantation and went on to develop SR-GvHD.
  • The next-step management options discussed included ruxolitinib, extracorporeal photopheresis, and belumosudil, though treatment options may depend on country-specific approvals and individual labels.
• Mohty concludes by summarizing that RWD can provide unique insights into patient journeys, treatment strategies, and outcomes, highlighting that they complement clinical trials through assessment of effectiveness and safety in more diverse patient populations.