Fed Circ denies Sun Pharma patent for alopecia treatment
Indian drugmaker had challenged PTAB decision that patent for new version of ruxolitinib was invalid as obvious | Decision hands a victory to US rival.
On Tuesday (August 22), the US Court of Appeals for the Federal Circuit upheld a decision invalidating a Sun Pharmaceutical patent relating to a new treatment for alopecia based on the medication ruxolitinib.
The Indian drugmaker lost its appeal against the conclusion of the US Patent Trial and Appeal Board that the claims of US patent number 9,249,149 were invalid as obvious. American rival Incyte had challenged the patent in 2017.
The ‘149 patent claimed a modified version of ruxolitinib, which Sun named CTP-543 and said had the potential to be a desirable treatment for autoimmune disease alopecia areata, which causes hair loss.
Ruxolitinib is already used to treat some blood and bone marrow cancers, but has some adverse side effects such as anemia, thrombocytopenia, dizziness and headaches. The process of deuteration, which was used to make Sun’s CTP-543, can positively impact how drugs are processed by the body and produce more favourable outcomes.
The FDA has given the compound “fast track” and “breakthrough therapy” designations, meaning its review as a new drug will be expedited.
However, the Board found the claims of the patent to be obvious over two prior patents (Rodgers and Shilling) and a marketing publication issued by the original owner of the ‘149 patent, Concert Pharmaceuticals.
Sun took issue with the PTAB’s analysis of the second part of the test for determining obviousness regarding new chemical compounds, “whether the prior art would have supplied one of ordinary skill in the art with a reason or motivation to modify a lead compound to make the claimed compound with a reasonable expectation of success”.
The firm said the Board failed to ask whether a person “would have been motivated to deuterate ruxolitinib to alter its pharmacokinetic properties”, whether they would have made the specific molecular modifications claimed in the patent, and whether they would have reasonably expected success in modifying ruxolitinib.
No FDA approval
Affirming the findings of the Board, Circuit Judges Hughes, Linn and Stark refuted these claims. They said that the PTAB had had “substantial evidence”—including the testimony of Incyte’s expert—that “the combined teachings of Shilling, Rodgers, and the Concert Backgrounder would have provided a skilled artisan with motivation to deuterate ruxolitinib, at its metabolic hotspots”.
An ordinarily skilled person “would have been motivated to make the specific modifications necessary to modify ruxolitinib to its deuterated analogs”, they opined.
Despite arguments put forward by Sun that its new drug “satisfies the long-felt need for an FDA-approved, evidence-based alopecia treatment”, the Judges felt that the firm had failed to prove this as CTP-543 lacked FDA approval as of yet.
“Nothing about Sun’s objective indicia evidence rebuts Incyte’s prima facie showing of obviousness,” they said.
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