Celldex Therapeutics has reported positive results from its Phase I study of CDX-301 (recombinant human Flt3L; rhuFlt3L) conducted in healthy volunteers.
The positive data from the study conducted at Rockefeller University supports the commencement of a pilot study in hematopoietic stem cell transplantation.
Celldex clinical science vice president Dr Michael Yellin said CDX-301 is well-tolerated and can effectively mobilise hematopoietic stem cell populations as a single agent in healthy volunteers.
"Based on the safety profile and the impressive increases observed for CD34+ stem cells and dendritic cells, we believe CDX-301 holds significant promise in both the allogeneic and autologous transplant setting, including the potential for combination with other molecules that could work in synergy with CDX-301 to further enhance the mobilisation of hematopoietic stem cell populations," Yellin said.
"Published pre-clinical Flt3L studies also suggest that CDX-301 could potentially improve engraftment and reduce the risk of graph versus host disease. This may be especially important for older patients and patients who are in poor health."
The study enrolled 30 healthy volunteers across seven cohorts.
Escalating doses of CDX-301301 (from 1mcg/kg to 75mcg/kg) as a five-day regimen was assessed in the first five cohorts, while CDX-301 (at 25mcg/kg) was evaluated in the final two cohorts as seven and 10-day regimens.
Short-term dosing of five days produced a median of 10-fold increases in CD34+ cells. On day 10 of dosing, more than a 100-fold increase in dendritic cells was observed in the peripheral blood.
Transient grade 1 lymphadenopathy was observed in six volunteers (all treated at the highest dose levels of 25mcg/kg and 75mcg/kg), while CDX-301 was well-tolerated.
Volunteers did not exhibit any anti-CDX-301 antibodies at any time from commencement to the end of study follow-up.