Dynavax drops 18.8% as Merck & Co ends accord

Shares in USA-based Dynavax Technologies Corp dropped 18.8% after Merck & Co decided to end a collaboration centered on the development of a  hepatitis B vaccine.

Earlier this year, the US Food and Drug Administration placed Heplisav  on clinical hold (Marketletter March 31) and later requested a review of  safety data, as well as as all available information on a single case of  Wegener's granulomatosis reported during a Phase III trial  (Marketletter April 28).

All rights to develop and commercialize Heplisav revert to Dynavax,  which says it will continue to evaluate regulatory options for the  development of the agent indicated for adults outside the USA and for  the global end-stage renal disease market, which the company estimates  represent 70% of the total market opportunity for this vaccine.