DESIGNATE siplizumab dose-finding study in recent-onset T1D
Terminated Phase 1/2 anti-CD2 antibody study in recent-onset T1D. Enrollment was held after greater-than-anticipated lymphocyte depletion; the partner then stopped development of siplizumab in autoimmunity.
Primary endpoints
- Number of participants with the specified T-cell phenotype response by week 12
Results so far
Eight adults were randomized, seven received siplizumab, and six had the two consecutive doses and viable samples required for the primary per-protocol analysis, versus 160 participants planned. Three of six met the composite T-cell phenotype-response definition (one at each of 0.08, 0.12, and 0.18 mg/kg; none at 0.22 mg/kg). This is an immune-phenotype signal, not clinical efficacy; the C-peptide and insulin-use outcomes were not posted and planned analyses were not produced because the sample was too small. There were no deaths or serious adverse events among the seven treated adults, but all seven had decreased CD4 lymphocytes recorded as a nonserious adverse event. The study had been held for greater-than-anticipated lymphodepletion before the pharmaceutical partner ended siplizumab development in autoimmunity.