On Thursday, April 27th, legal data analytics firm Lex Machina released a Hatch-Waxman/ANDA litigation report detailing trends and key findings from pharmaceutical cases filed in U.S. district courts between January 1st, 2009, and March 31st, 2017. More than eight years worth of data shows that patent infringement case filings in response to abbreviated new drug applications (ANDAs) filed with the U.S. Food and Drug Administration (FDA) declined in 2016 for the first time in three years. According to Lex Machina data scientist Brian Howard, litigation filed in response to ANDA filings with the FDA follows very different dynamics than other patent litigation. “The filing of these cases is not permissive in the same way that a typical case in district court is,” Howard said. “There’s a strict period in which action has to be brought or the rights are lost.” Federal regulatory code governing FDA market approval for generic drug ANDAs mandates that a pharmaceutical patent owner must bring suit within 45 days of the ANDA filing or the FDA can approve the generic for sale on the market.

Although other Lex Machina reports have pointed out the effects that high-volume plaintiffs have on volatility in overall patent infringement litigation, no such designation is made in the company’s ANDA report. Again, this has to do with the non-permissive nature of ANDA litigation and the dynamics behind why generic drug makers file ANDAs in the first place. “ANDA litigation, in some sense, has a clumsiness to it,” Howard said. “When a drug is likely to go off-market, typically more than one generic maker will want to make a generic.” Lex Machina has also scraped data from the FDA’s Orange Book in order to create word clouds which indicate the pharmaceuticals which have spawned the most ANDA case filings. The antipsychotic drug Abilify has been at the center of 63 ANDA cases since 2009, the single-largest amount of case filings over generic versions of a branded drug, just slightly ahead of the pain relief drug Oxycontin (59 cases since 2009).

As Lex Machina’s ANDA report points out, the top parties in ANDA litigation tend to primarily be either claimants or claim defendants; there aren’t many companies who play both sides of the fence in this space. The top party in ANDA litigation is Irish-American pharmaceutical giant Allergan (NYSE:AGN), a corporation which includes Actavis and Watson as subsidiaries. Since 2009, those entities have been seen in 427 ANDA cases and have shown up as a claim defendant in 85 percent of cases. Second-place Mylan (NASDAQ:MYL) of Canonsburg, PA, has been involved in 290 ANDA cases since 2009 and has been a claim defendant in each case. The party with the largest number of ANDA case filings who has served primarily as a claimant is UK-based drugmaker AstraZeneca (NYSE:AZN), which has been a claimant in 100 percent of the 156 ANDA cases it has been a party to since 2009.

The bases for findings of patent invalidity are also different when comparing ANDA cases to all other patent infringement litigation. Nearly 70 percent of the ANDA cases which find patent invalidity do so on Section 103 grounds for obviousness. By contrast, slightly more than 55 percent of patent invalidity findings in other patent litigation reach invalidity on Section 102 grounds for anticipation/novelty. “So much of ANDA litigation is focused on patents covering not just the ingredients but what effect the pharmaceutical has,” Howard said. Given that there’s a larger proportion of patents focused on the effects, it seemingly could be the case that obviousness arguments are easier to make if pointing out that the patent covers the reformulation of a drug which already existed.