Medical Malpractice Insurance Antitrust Act of 2005 - Provides that: (1) nothing in the McCarran-Ferguson Act shall be construed to permit commercial insurers to engage in any form of price fixing, bid rigging, or market allocations in connection with the conduct of the business of providing medical malpractice insurance; and (2) such provision shall not apply to the information gathering and rate setting activities of any state insurance commissions or any other state regulatory body with authority to set insurance rates.