Trial Eligibility Requirements Capture Only a Fraction of Adults With Sickle Cell Disease: Julie Kanter, MD

Current clinical trial eligibility criteria for new therapies in sickle cell disease (SCD) capture only a small fraction of the adults living with the condition, according to data presented at the European Hematology Association 2026 Congress by investigator Julie Kanter, MD, codirector of the Lifespan Comprehensive Sickle Cell Center at the University of Alabama at Birmingham, where she is also a professor in the divisions of hematology and oncology.

At the meeting, Kanter explained to The American Journal of Managed Care^® that her study, “Current Clinical Trials for New Therapies in Sickle Cell Disease Do Not Adequately Represent the Patient Population," was designed to address 2 long-standing concerns: whether current trial eligibility criteria reflect the needs of the general adult SCD population and whether acute pain crisis, the end point most trials rely on, is an appropriate measure given that many exclusion criteria have been built around it.

To answer this, the investigators linked 3 national data sources using hash tokenization to preserve patient privacy: the Globin Regional Network for Data and Discovery (GRNDaD) registry; the CDC's Sickle Cell Data Collection program; and the American Society of Hematology Research Collaborative's electronic medical record-based data hub.

Starting from 456 adults aged 18 to 65 in GRNDaD, the smallest of the 3 datasets, the researchers sequentially applied common trial exclusion criteria, including end-stage renal disease and chronic transfusion therapy, narrowing the cohort to about 160 patients. Applying a requirement of 2 to 10 or 2 to 12 patient-reported acute pain crises in the prior year reduced that number to 45 patients, or just 9.9% of the original population.

Kanter said these findings indicate that SCD remains underserved by new drug development. At the same time, therapies being created are designed for and tested in only a small fraction of the population they are meant to treat. Consequently, she framed the findings as a call for more individualized post-authorization monitoring once new drugs reach the broader SCD population, noting that any approved therapy carries inherent risk when extended beyond such a narrow trial population.

Kanter added that she was not surprised by the small number of patients represented based on her own experience in the clinic.

“I wasn't surprised because I do a lot of clinical trial work, and I'm constantly looking through patients, talking to them in clinic, trying to see who would qualify if I don't feel like their current therapies are sufficient,” she concluded.