MSD and Dynavax: Phase III Heplisav trial meets endpoint

Merck, Sharp and Dohme and Dynavax Technologies have announced the phase III clinical trial of Heplisav (investigational heptatitis B vaccine) has met its primary endpoint.

The vaccine is currently being co-developed by MSD and Dynavax for use in patients with end-stage renal disease.

In the recent Phast study, the vaccine was evaluated following administration at zero and one month periods, compared to a three-dose regimen of existing hepatitis B vaccine Engerix-B administered at zero, one and six month intervals.

The vaccine achieved its primary endpoint of the proportion of subjects who developed hepatitis B antibodies after being administered with the compound.

In total, 95.1 per cent of patients administered with Heplisav developed protective antibodies to the disease at 12 weeks compared to 81.1 per cent taking Energix-B measured at 28 weeks.

“Heplisav is based on Dynavax’s proprietary immunostimulatory sequence (ISS) that specifically targets Toll-Like Receptor 9 (TLR9) to stimulate an innate immune response,” MSD said.

It added Heplisav combines an HBV surface antigen with ISS and aims to boost the speed of protection offered.

Under the terms of the co-development agreement between the firms announced in November 2007, Dynavax received an initial fee of $31.5 million (15 million pounds) and became eligible for a further $105 million in sales and development milestone payments.