bluebird bio (BLUE) reported Wednesday that its phase 2/3 Starbeam study of its investigational Lenti-D gene therapy in boys 17 years of age and under with cerebral adrenoleukodystrophy (CALD), has met its enrollment goal; it also reported initial data from ALD-103, the ongoing observational study of outcomes from allogeneic hematopoietic stem cell transplant (allo-HSCT) in boys 17 years of age and under with CALD.
The phase 2/3 Starbeam study had a total study population of 31 patients, as reflected by reported data as of April 25. Of these 31 patients, 29 have received Lenti-D and the median follow-up for all treated patients was 34 months. The primary efficacy endpoint of the Phase 2/3 Starbeam study is the proportion of patients who are alive and free of major functional disabilities (MFD) at month 24. Of the 17 patients treated with Lenti-D who completed 24 months of follow-up, 15 patients (88 percent) were alive and MFD-free. An additional 12 patients have received Lenti-D in the Phase 2/3 Starbeam study. While these patients have not reached the primary endpoint of 24-month follow-up, there have been no MFDs reported as of April 25.
Meanwhile, initial results from the ALD-103 study showed that Allo-HSCT has been successfully used to treat CALD but may be associated with adverse immunologic complications. The ongoing observational study ALD-103 is designed to assess safety and efficacy outcomes of this treatment option in boys 17 years of age or younger with CALD.
As of April 25, 41 pediatric patients were enrolled in the ALD-103 study and had undergone allo-HSCT. Thirty-one patients received cells from unrelated donors and 10 received cells from a related donor. Initial results were in line with safety and efficacy outcomes reported in the literature for allo-HSCT in patients with CALD.
There were six transplant-related deaths at one year; none of these patients had a matched sibling donor. Engraftment failure was reported in five patients; none of these patients had a matched sibling donor and all received a second transplant.