Neurim prevails against Mylan in suit over insomnia drug

Neurim Pharmaceuticals has won its case against generics drug maker Mylan at the  English High Court, which held that its patent for a treatment for insomnia was valid and had been infringed in a ruling handed down on December 4.

According to the filing, Neurim filed the patent, EP (UK) 1,441,702 B1, in August 2002, which if not revoked sooner, will expire on August 12, 2022.

The patent covers the prolonged release of pharmaceutical formulations from melatonin to improve the restorative quality of sleep in a patient suffering from insomnia. Sold under the brand name Circadin, the medicine is authorised for use in the European Union.

In June, Neurim and Flynn Pharma sought interim injunctive relief against Mylan, after it found that the generics maker was planning to make a version of the best-selling treatment.

In late October, Mylan contended that the patent was invalid on the grounds that the patent lacked novelty as it was anticipated by an article entitled “ Melatonin Replacement Therapy of Elderly Insomniacs” (Haimov 1995); and because the patent is obvious and did not involve an inventive step by reason of prior art.

Mylan also held that the patent is insufficient and may be revoked on the ground that “the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art”.

The court, however, held that Mylan’s expert testimony lacked the necessary understanding of the “nuts and bolts” of patents and patent law and that this had the “unfortunate effect of skewing in unpredictable ways his evidence and rendering it unreliable”.

It also found Mylan's “definition of the skilled person/team to be so vague as to be useless”. The court held that in the articles cited as proof of prior art, that a role for melatonin was not indicated for insomnia, but might have been indicated for Circadian Rhythm Sleep Disorder, a disorder unrelated to primary insomnia.

Instead, the court opted for the expert evidence offered by Neurim that held that while “it was known that melatonin could be useful in the treatment of circadian rhythm disorders... it was not thought to be useful for the treatment of primary insomnia”.

Validity of patent upheld

The court found that the patent’s claims of the use of melatonin for “improving the restorative quality of sleep in a patient suffering from primary insomnia characterised by non-restorative sleep” leaves “no room for any misunderstanding or alternative meaning within the terms of the patent”.

The court also rejected Mylan’s suggestion that the patent lacks novelty. Neurim stated that in the 1995 Haimov study, that “none of the patients in the study populations are described as having been diagnosed with primary insomnia characterised by non-restorative sleep or nonorganic insomnia characterised by poor quality of sleep…”

The court accepted Mylan’s argument that it is clear that the study was using the term “sleep quality” in a non-technical sense. Mylan defended the study, suggesting that it was focussed on individuals suffering from primary insomnia, but the court found that it was unable to explain the failure on the part of the authors to apply the correct diagnostic criteria.

The court also failed to see how a skilled person could understand that the study had anything to do with primary insomnia and “still less with quality of sleep / non-restorative sleep…[T]he study was, quite obviously on its face, concerned with something altogether different,” it said.

It concluded that the disputed study in no way anticipated the patent and that the patent is novel. “The skilled person, having the common general knowledge..., but lacking inventive capacity, would draw nothing from Haimov 1995 to render the invention of the patent obvious,” it stated.

Mylan also argued that the patent had been anticipated by a webpage advertising the treatment, Melatonex. But the court found that the page “does no more than re-hash the putative benefits of melatonin for sleep problems”, with loose reference to circadian rhythm issues and the theory that melatonin levels need to be “topped up” in some people.

“There is no suggestion that the product would be of benefit to those suffering from primary insomnia, and there is no reference whatsoever to non-restorative sleep”, it said, adding that the notion that the Melatonex webpage could motivate the skilled person to conduct further research is similarly “fanciful”.

The court concluded that the challenges to the validity of the patent had all failed and that Mylan is either threatening to, or is, infringing the patent. It ruled, however, that Flynn had no right to bring a claim independent of Neurim because it was not an exclusive licensee.

The global market for melatonin in 2019 was worth $700 million and is expected to reach more than $2 billion in the next five years.

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