Genentech, the US biotechnology group, launched a vigorous defence against Roche’s planned $42bn takeover on Monday, claiming that the bid sharply undervalued its worth and hinting it could undermine its innovative culture.

Arthur Levinson, Genentech’s chairman and chief executive, told investors at a meeting that the company was “on track” to meet all its goals and grow sharply in the years ahead on the back of new drug launches.