The PTAB issued a Final Written Decision in IPR2016-00258, wherein Petitioner Green Cross Corp. challenged claims 1-3, 16, and 17 of Shire Human Genetic Therapies, Inc.’s U.S. Patent No. 9,051,556. Green Cross, which is developing a biobetter of Shire’s Elaprase (idursulfase) for Hunter syndrome, had argued that the challenged claims were obvious under 35 U.S.C. § 103 based on a prior art reference, Jin, in view of other prior art. The Board found that Green Cross failed to carry its burden of showing obviousness because Shire antedated the Jin reference by showing reduction to practice of all claimed elements prior to the critical date of Jin.