Shares in Moderna fell after a patent court ruled against the biotech company in a case brought by Moderna against rival Arbutus over the status of certain legacy patents last week. Moderna's shares had been on the ascendancy in recent weeks thanks to the progress the US company has made in developing a vaccine for COVID-19. In mid July, the value of its shares rose 15% after the company announced that initial trials for the vaccine had found no serious side effects in human volunteers. The ruling is the third in a series of cases brought by Moderna against Arbutus last year, and centers on an Arbutus patent covering lipid formulations for the delivery of nucleic acids, according to Fierce Biotech. When filing their patent, Arbutus said the technology is based on a "surprising discovery," but Moderna argued that the innovation would have been obvious to anyone in the field. In a ruling published last Thursday, the Patent Trial and Appeal Board sided with Arbutus. Moderna have said that the ruling will not affect the development of its COVID-19 vaccine, known as mRNA-1273. The ruling "relates to Moderna’s challenge to certain legacy patents held by Arbutus, commenced well before the development of mRNA-1273," the company said in a statement. "These actions were taken by Moderna in response to the longstanding aggressive posture taken by Arbutus and its predecessor company against many developers of nucleic acid-based therapeutics. Through its actions, Moderna successfully overturned one legacy patent held by Arbutus and invalidated the broadest claims of a second one."Moderna has licenced lipid nanoparticle (LNP) technology from Acuitas in order to enable the delivery of mRNA. The ClinicalTrials.gov entry for Moderna's vaccine trials describes the experimental vaccine mRNA-1273 as "a novel lipid nanoparticle (LNP)-encapsulated mRNA-based vaccine that encodes for a full-length, prefusion stabilized spike (S) protein of SARS-CoV-2." However, the company distanced the ruling from the vaccine, explaining: "Moderna’s continued development of its proprietary LNP formulation technology and manufacturing processes have advanced well beyond the technology described in these legacy Arbutus patents. Our improved proprietary LNP formula, used to manufacture mRNA-1273, is not covered by the Arbutus patents. Moderna is not aware of any significant intellectual property impediments for any products we intend to commercialize, including mRNA-1273."Shares in Arbutus rose following the ruling, peaking on Friday morning at 7.96 USD, although they had dropped back by Friday afternoon to close on 4.96 USD. Moderna's shares, conversely, dropped to a low of 69.08 USD on Friday morning, but had rallied by close of day to reach 73.21 USD.