Human Fetal Cell Therapy in Huntington's Disease: A Randomized, Multicenter, Phase II Trial.

Background: Huntington's disease is a rare, severe, inherited neurodegenerative disease in which we assessed the safety and efficacy of grafting human fetal ganglionic eminence intrastriatally.

Methods: Patients at the early stage of the disease were enrolled in the Multicentric Intracerebral Grafting in Huntington's Disease trial, a delayed-start phase II randomized study. After a run-in period of 12 months, patients were randomized at month 12 to either the treatment group (transplanted at month 13-month 14) or the control group and secondarily treated 20 months later (month 33-month 34). The primary outcome was total motor score compared between both groups 20 months postrandomization (month 32). Secondary outcomes included clinical, imaging, and electrophysiological findings and a comparison of pregraft and postgraft total motor score slopes during the entire study period (month 0-month 52) regardless of the time of transplant.

Results: Of 54 randomized patients, 45 were transplanted; 26 immediately (treatment) and 19 delayed (control). Mean total motor score at month 32 did not differ between groups (treated controls difference in means adjusted for M12: +2.9 [95% confidence interval, -2.8 to 8.6]; P = 0.31). Its rate of decline after transplantation was similar to that before transplantation. A total of 27 severe adverse events were recorded in the randomized patients, 10 of which were related to the transplant procedure. Improvement of procedures during the trial significantly decreased the frequency of surgical events.We found antihuman leucocytes antigen antibodies in 40% of the patients.

Conclusion: No clinical benefit was found in this trial. This may have been related to graft rejection. Ectopia and high track number negatively influence the graft outcome. Procedural adjustments substantially improved surgical safety. (ClinicalTrials.gov NCT00190450.) © 2020 International Parkinson and Movement Disorder Society.