Alkermes plc, of Dublin, said in a document filed with the SEC, that on June 3 the U.S. Patent and Trademark Office accepted two separate petitions for inter partes review (IPR) filed by Luye Pharma Group Ltd., challenging U.S. Patent number 6,667,061, which is an Orange Book-listed patent for each of Bydureon, Risperdal Consta and Vivitrol. The company has three months to respond, following which the U.S. PTO has a further three-month period to decide whether or not to institute a review of the challenged claims of the '061 patent. It said it will oppose Luye's requests to institute the challenge of the '061 patent, and, if the U.S. PTO institutes such challenge, the company will oppose the full proceedings and vigorously defend the '061 patent.