Voxelotor was generally well tolerated at a 900-mg once-daily oral dose. One patient developed grade 2 diarrhea after increasing the dose to 1,500 mg, but symptoms resolved after returning to the 900-mg dose. Another patient had transient mild diarrhea on 900 mg of voxelotor; the symptoms resolved without changing or stopping the drug, Dr. Bronté said. There were no serious treatment-related adverse events.
Among this seriously ill population, two patients died after beginning voxelotor treatment, but both deaths were judged to be unrelated to the treatment. Dr. Bronté reported that the two deceased patients, one of whom was on voxelotor for 16 months and the other for 7 months, did experience reduced transfusion needs and reduced VOC-related hospitalizations while on the drug, experiences that were similar to the surviving members of the cohort.
“Voxelotor administered via compassionate use demonstrated large improvements in anemia and hemolysis, including in patients with lower baseline hemoglobin than studied in clinical trials to date,” Dr. Bronté said.
Taken together with clinical improvements and improved patient-focused outcomes among a severely affected population, “these data … support ongoing investigation in controlled clinical trials to confirm the benefits of voxelotor in a broad range of patients with SCD,” she said.
The study was supported by Global Blood Therapeutics, the manufacturer of voxelotor. Dr. Bronté reported having no other conflicts of interest.