Rob Clark

Pharmaceutical giant Wyeth has accused Merck Sharp & Dohme of a “baseless” patent invalidity case, saying on the second day of trial over the world’s best selling vaccine that the development of its patented Prevnar 13 pneumococcal shot was anything but obvious, as its rival contends.

A showdown between global pharmaceutical giants over the world’s best selling vaccine began Monday in Federal Court, with Merck Sharp & Dohme claiming three patents for Prevnar 13 sold by Pfizer’s Wyeth are invalid and that its own vaccine offers greater protection against pneumococcal bacteria.