Three Democratic members of the US House are pressing the US Federal Trade Commission to conduct an in-depth analysis of the proposed $29 billion acquistion of Medco Health Solutions by Express Scripts. The move comes shortly after the agency already asked the pharmacy benefit managers for additional information about the deal, which was announced two months ago (see this).

“If combined, the newly merged PBMs would control one-third of total 2011 PBM market share and 60 percentof the market share for mail-order drugs. One analyst noted that the merger would shift the balance of competition in the PBM market, changing a market with “three equal competitors” into one with “one huge player and a distant second and third,” wrote California’s Henry Waxman, New Jersey’s Frank Pallone and Colorado’s Diana DeGette in a September 9 letter (look here).

“Changing industry dynamics raise additional questions about this merger and its impact on consumers and healthcare costs. Expensive specialty drugs are the fastest-growing areas of the pharmaceutical market, and their distribution occurs primarily through large, mail-order service by PBMs,” they continued. “…The proposed merger would affect hundreds of millions of Americans with private health insurance and have a potentially significant impact on drug cost for government programs lncluding Medicare Part D, Medicaid, the Federal Employee Health Benefits Plan, and TriCare” (We should note that Medco recently lost the Federal Employees Health Benefits Program to CVS Caremark).

The FTC is under pressure to further scrutinize the proposed deal, given criticism that the agency was too lax when the CVS pharmacy chain purchased Caremark, the other large PBM in the triumvirate that dominates the US market. There was no so-called second request by the FTC during that review, although a subsequent investigation into the combination remains ongoing.

Not surprisingly, various rivals strenuously oppose the Express Scripts deal to buy Medco, including the National Community Pharmacists Association (read here) and Independent Specialty Pharmacy Coalition (see this).

UPDATE: An Express Scripts spokesman send us this: “Although the timeline for the antitrust review process is not fixed, we are confident of a positive review and we anticipate the merger will close, as expected, in the first half of 2012. As the FTC has noted on several occasions, PBMs use their resources to effectively lower the cost of quality prescription drug care – that’s in the best interest of consumers.”