Genticel crashes after HPV immunotherapy misses interim efficacy endpoint

A human papillomavirus (HPV)-focused immunotherapy in development at Genticel (EPA:GTCL) has failed to outperform the placebo in an interim review of data from a Phase II trial. The news spooked investors, triggering an almost 30% collapse in the share price of Genticel on Euronext Paris.

After 12 months of the trial, Genticel was unable to tell whether the immunotherapy, GTL001, was any more effective than placebo at clearing infections with HPV 16 or 18. Of the 117 people to take GTL001 in the trial, 57 experienced viral clearance at 12 months. However, with 46 of the 116 people in the placebo arm also clearing the virus, a 40% rate that is at the lower end of those generated in previous studies, the performance of GTL001 fell short of statistical significance. Investors viewed the data as a blow to Genticel's chances of establishing GTL001 in the cancer prevention pathway.

Labège, France-based Genticel is publicly presenting a more optimistic viewpoint. The company picked out the performance of two prospectively defined subgroups--participants who had normal cytology or were aged under 30 years old--as positives to take away from the interim review. Clearance rates in the treatment arms of these subgroups were notably higher than those obtained from the whole population, resulting in GTL001 statistically outperforming the placebo in these patients. Genticel thinks the subgroup data bodes well for when it performs the 18-month review.

Margaret Stanley, a professor at the University of Cambridge and adviser to Genticel, looked to the experience of Dendreon's Provenge, the pioneering immunotherapy also known as sipuleucel-T, for reasons to be optimistic about the 18-month data. "It has been noted with both other experimental and licensed onco-immune therapies, including the autologous cellular immunotherapy, sipuleucel, that clinical activity is observed following a significant lag period," Stanley said in a release. "Therefore, I look forward to the availability of the 18-month clearance data."

- read the release (PDF)