PTAB Upholds Breast Cancer Treatment Drug Patent

Oct 29, 2015

Reading Time : 1 min

The ’856 patent, owned by ImmunoGen Inc., covers the drug, Kadcyla, which is used to treat HER2-positive metastatic breast cancer. The ’856 patent claims an immunoconjugate comprised of Herceptin, which is a humanized form of a mouse monoclonal antibody, and a maytansinoid, which has cytotoxic properties. Phigenix argued that the claims of the ’856 patent were obvious in light of a prior art reference, Chari 1992. Chari 1992 also discloses an immunoconjugate of a humanized form of a mouse monoclonal antibody and a maytansinoid. Petitioner argued that it would have been obvious to substitute Herceptin for the antibody disclosed in Chari 1992. ImmunoGen contended that at the time the ’856 patent was filed in March 2000, Herceptin-maytansinoid immunoconjugates would have been expected to cause toxicity in the patient’s liver. The PTAB ruled that, given the references disclosing the toxic effect that would have been expected from a Herceptin-maytansinoid immunoconjugate, it would not have been obvious to an ordinary artisan to substitute the Chari 1992 antibody with Herceptin. 

Phigenix had also filed a petition seeking inter partes review of U.S. Patent No. 7,097,840, which was also a patent for Kadcyla. The PTAB declined to institute review in that case, finding that it was unlikely that Phigenix would prevail on its claims.

Phigenix, Inc. v. ImmunoGen, Inc., IPR2014-00676, Paper No. 39, (PTAB Oct. 27, 2015).

Share This Insight

Previous Entries

IP Newsflash

December 9, 2025

The Federal Circuit recently denied a petition for a writ of mandamus that challenged the PTO Director’s reliance on “settled expectations” to discretionarily deny two inter partes review (IPR) petitions. In so doing, the court explained that, while it was not deciding whether the Director’s use of “settled expectations” was correct, the petitioner’s arguments about what factors the Director may consider when deciding whether to institute an IPR or post-grant review (PGR) are not generally reviewable and did not provide sufficient basis for mandamus review here.

...

Read More

IP Newsflash

December 5, 2025

District courts are split on whether a complaint can provide the required knowledge for post-suit indirect and willful infringement in that same lawsuit. Chief Judge Connolly in the District of Delaware recently confirmed that, consistent with his prior opinions, the complaint cannot serve as the basis for knowledge for either a claim of post-suit indirect infringement or a demand for willfulness-based enhanced damages in that lawsuit.

...

Read More

IP Newsflash

December 3, 2025

The Federal Circuit recently held that a patentee acted as its own lexicographer to define a claim term even though it did not explicitly define the term. Rather, because the patentee consistently and clearly used two terms interchangeably to describe the same structural feature and did so in all of the embodiments in which the feature appeared, the patentee impliedly gave the term its own, unique definition.

...

Read More

IP Newsflash

December 2, 2025

The Federal Circuit recently held an asserted patent was not entitled to its priority date because the priority application lacked written description support for the asserted claims. In so doing, the court explained that broad disclosures that do not provide reasonably specific support for narrower claims do not meet the written description requirement. The court also considered whether the inventor’s testimony showed they possessed the full scope of the claimed genus at the priority date or whether it was more likely the inventors first became aware of the claimed embodiments from public disclosures of the accused product.

...

Read More

© 2025 Akin Gump Strauss Hauer & Feld LLP. All rights reserved. Attorney advertising. This document is distributed for informational use only; it does not constitute legal advice and should not be used as such. Prior results do not guarantee a similar outcome. Akin is the practicing name of Akin Gump LLP, a New York limited liability partnership authorized and regulated by the Solicitors Regulation Authority under number 267321. A list of the partners is available for inspection at Eighth Floor, Ten Bishops Square, London E1 6EG. For more information about Akin Gump LLP, Akin Gump Strauss Hauer & Feld LLP and other associated entities under which the Akin Gump network operates worldwide, please see our Legal Notices page.