Whether consolidation begets consolidation in the drug industry is often debated. What's not debatable, though, is that consolidation begets speculation about more consolidation.

That's driving up shares of several biotech companies Monday, after drug giant Pfizer announced its $14 billion deal for cancer drug developer Medivation. The deal price, of $81.50 per Medivation share in cash, is a 21 percent premium to where Medivation shares closed Friday, and is significantly higher than the $52.50 a share put on the table earlier this year by French competitor Sanofi.