US Patent office rejects Amgen's petition against Humira formulation patents potentially delaying market entry of ABP 501

• One strategy through which companies have been attempting to gain biosimilar market entry utilizes IPR (Inter Partes Review) Petitions
  
• IPRs offers a legal strategy whereby a biosimilar developer can test the validity of innovator patents prior to filing
  
• This strategy is increasingly being adopted.  Amgen filed IPR petitions in Jun 2015 against Humira US formulation patents: 8,916,157 and 8,916,158
• Coherus subsequently filed IPR Petitions against AbbVie patents claiming 40mg q2w dosing for rheumatoid arthritis (8,889,135, 9,017,680, 9,073,987).  Boehringer Ingelheim also attacked this dosing strategy, petitioning 8,889,135 in Dec 2015
• A legal decision on the Coherus petition is expected mid-2016, however in the meantime Amgen’s initial petitions have now been rejected by the patent office

Comments:  Amgen filed ABP 501, its biosimilar adalimumab, in the US on Nov 25th.  This is believed to be the first adalimumab biosimilar filed in the US.  Abbvie has previously commented that one of its biosimilar defense strategies will include patent defense, including a broad estate of relatively recent, method of use, dosing and formulation patents.  The patents that Amgen petitioned were two of these formulation patents and by rejecting the company's IPRs the Patent Office has maintained one barrier to Amgen finding a way through Abbvie's IP estate.  Claims in the two patents are of interest.  In particular, we understand that these patents claim formulations which support a longer shelf life, stability if frozen, an absence of citric acid and the possibility of neutral pH.  These properties are distinct from the Humira formulation currently available in the US and if the Patent Office had decided the claims were indeed unpatentable, Amgen would not only have been offered a route to early market entry, they may also been offered a competitive advantage over Humira.  In this respect Abbvie has developed a new formulation Humira.  This has recently been approved in the US and EU and is characterized by low volume/high concentration and also reduced injection site pain (due to the lack of citric acid).  This new formulation appears to have different characteristics to those claimed in the patents petitioned by Amgen and may represent a next level of Abbvie's defense if Amgen (or others) launch a biosimilar adalimumab.  For the moment however Amgen will have to develop new strategies, one of which is contesting the patents through the court system.  This however will take a number of years