Shares of AbbVie Inc. (ABBV) fell 4.7% on Thursday after short seller Citron Research called the company "the next great drug short" and indicated that it plans to release a series of reports "detailing the Dirty Money." (See also: How AbbVie Makes its Money.)

Citron issued a 12-month price target of $60 on Abbvie shares, reflecting a more than 33% downside from Thursday's closing price of $89.95. 

The news comes a day after U.S. Food and Drug Administration Commissioner Scott Gottlieb tore into drugmakers for allegedly blocking smaller rivals from introducing cheaper biosimilar drugs to the market. Citron called the remarks, and the "removal of safe harbor," which could threaten drug rebates, a "DIRECT hit on Abbvie's abuse of Humira." 

The FDA's Plan to Facilitate Biosimilars

The tweet referred to AbbVie's top-selling drug Humira, an anti-inflammatory therapy that has been a top target for rivals making biosimilar drugs, as noted by MarketWatch. Gottlieb spoke of companies that dangle "big rebates to lock up payers in multiyear contracts right on the eve of biosimilar entry."  

While Gottlieb's FDA has no jurisdiction over potential antitrust claims against pharmaceutical giants like AbbVie, his new Biosimilars Action Plan would make it easier for biosimilar drugs to come to market. The FDA commissioner claims that Americans could have saved $4.5 billion in 2017 if FDA-approved biosimilars had been available to U.S. patients. 

$ABBV the next great drug short. TGT price $60 Gottlieb's comments for biosimilars and the removal of safe harbor is a DIRECT hit on Abbvie's abuse of Humira. Citron to release a series of reports detailing the Dirty Money. POTUS, AMZN, and now FDA on the case $60 in 12 months
— Citron Research (@CitronResearch) July 19, 2018

Other Big Pharma players have been criticized for leveraging contractual negotiations so to prevent the uptake of biosimilars. Johnson & Johnson (JNJ) was accused of using this strategy to protect its rheumatoid arthritis therapy Remicade in a lawsuit filed against it by Pfizer Inc. (PFE). 

ABBV stock has fallen 8% year-to-date (YTD), compared to the S&P 500's 4.3% gain over the same period. The SPDR S&P Pharmaceuticals ETF (XPH) is up 2.5% YTD. (See also: Buy Alibaba, Not Amazon: Short-Seller Citron.)