To further posit on my above post, the insurance industry tried to argue in the 1970s that Mccarran-Ferguson, a law which provides limited exemptions to 15 USC for insurance firms, shielded them -- and pharmacies -- from prosecution under these laws.

The case went to the Supreme Court and the insurance and pharamacy firms lost.
https://supreme.justia.com/cases/federal....

Now Sen. Rand Paul has introduced legislation that would exempt the healthcare industry from all federal antitrust laws.  Here is the text that I found via Google:

(a) Application of the Federal Antitrust Laws to Health Care 
Professionals Negotiating With Health Plans.--
(1) In general.--Any health care professionals who are 
engaged in negotiations with a health plan regarding the terms 
of any contract under which the professionals provide health 
care items or services for which benefits are provided under 
such plan shall, in connection with such negotiations, be 
exempt from the Federal antitrust laws.