There's no evidence to suggest that granting makers of biologic drugs 12 years of market monopoly would “guarantee higher drug prices” for these drugs. In fact, shortening the monopoly period is likely to raise the price of biologics.
 

Academic research shows that a biologic producer needs more than 12 years of exclusive sales to break even on the development costs of a new drug. If a firm faces competition from biosimilars any earlier, it would probably raise prices for its innovator biologics, as it must recoup its initial investment within a much smaller monopoly window. As a result, cutting-edge medicines would become even less affordable.