PARASOL, Endpoints, and Rethinking Clinical Trials in Glomerular Disease

In this episode, the conversation broadens to the PARASOL framework and the evolving science of endpoints and trial design across glomerular diseases.

Gillespie briefly defines PARSOL, which is French for umbrella, as a unifying initiative conceived with leaders like Laurel Damashek to protect and guide the community toward better trial designs and therapeutic options across multiple diseases. PARASOL 1.0 focused on focal segmental glomerulosclerosis (FSGS), and newer extensions now target membranous nephropathy and APOL1-mediated kidney disease, with ambitions to cover many glomerular diseases over the coming decade.1,2

The core philosophy of PARASOL is collaborative data sharing. For example, rather than each company independently shouldering the burden of building evidence for regulatory endpoints, sponsors with competing drugs work together, pooling clinical trial and registry data to evaluate potential surrogate endpoints. Gillespie underscores the importance of this shift, echoing other leading voices in the field who advocate for collaboration as essential to progress in rare and complex diseases.1,2

Gillespie then gives a concise tutorial on endpoints:

• In regulatory terms, endpoints must reflect how a patient feels, functions, or survives.
• Validated surrogate endpoints (e.g., LDL cholesterol in atherosclerotic disease) have strong, long-term data linking biomarker changes to clinical outcomes.
• Reasonably likely surrogate endpoints support accelerated approval, such as proteinuria reductions in IgA nephropathy.
• Candidate surrogate endpoints, the focus of Parasol, are being evaluated for their potential to move up the hierarchy.

She notes that while some sponsors try to copy-paste the IgA nephropathy (IgAN) “recipe” to other diseases, this is inappropriate because each glomerular disease has unique pathobiology and mechanisms of action. Hence, disease-specific PARASOL projects for FSGS, membranous, APOL1, and beyond.

The episode also touches on Alport syndrome, where the ASSENT initiative is playing a similar endpoint-defining role, with roughly 45 companies interested.

Finally, Gillespie discusses practical trial challenges, including limited numbers of glomerular specialists, recruitment bottlenecks, and the need to mobilize community nephrologists. She highlights clinical trial boot camps that train new investigators and shows how collaborations with patient organizations are critical for dissemination, pricing, and implementation once drugs are approved.

Featured Experts

Barbara Gillespie, MD, Chief Medical and Strategy Officer of the International Society of Glomerular Disease and Adjunct Professor at the University of North Carolina

Tobias Huber, MD, President of the International Society of Glomerular Disease, Chair of the Center of Internal Medicine; Director of the III. Department of Medicine (Nephrology, Rheumatology, Endocrinology and Transplantation); and Director of the Hamburg Center for Kidney Health at the University Medical Center Hamburg-Eppendorf

Editors’ Note: Gillespie reports no relevant disclosures. Huber reports relevant disclosures with Boehringer Ingelheim, Novartis, Alexion, Pfizer, Retrophin-Travere, and Fresenius Medical Care.

References

1. Neuen B, Wadhwani, S. Kidney Compass: The PARASOL Initiative, with Laura Mariani, MD, MS, and Daniel Gale, PhD, MB BChir. Hcplive.com. Published December 11, 2024. Accessed March 6, 2026. https://www.hcplive.com/view/kidney-compass-the-parasol-initiative-with-laura-mariani-md-ms-and-daniel-gale-phd-mb-bchir

2. Neuen B. Kidney Compass: PARASOL Findings and Implications for FSGS. HCPLive. Published 2024. Accessed March 6, 2026. https://www.hcplive.com/view/kidney-compass-parasol-findings-and-implications-for-fsgs