Originally published in Pharma in Focus

MSD's tactics in a patent opposition case against Genentech involving an unnamed interleukin-17 inhibitor have been described by one lawyer as "surprising", but there are still legal avenues open for the company.

"I'm surprised at the level they went to in this case," said Bill Pickering, partner at Davies Collison Cave, a patent lawyer not involved.

A judgement was handed down last Friday, in a case which has been going since MSD launched it in 2010. The commissioner of patents found MSD's initial opposition successful but gave Genentech time to amend the patent, which was subsequently accepted. MSD then appealed this decision.

"I am not sure why they would have taken this path," Dr Pickering said "In principle, you can't appeal subsequent decisions from the patent office."

It is not clear exactly which, if any, product MSD might be concerned Genentech's patent infringes, but IL-17 blockers for inflammatory conditions like psoriasis are a highly anticipated new class of treatments.

Meanwhile, MSD is by no means out of options, Dr Pickering said. The patent will now be granted, but MSD can then launch a revocation case in the Federal Court if it wishes.

In fact, revocation cases can be easier, he explained. In pre-grant opposition, the burden of doubt rests with the patent applicant, whereas this is not the case in revocation cases. The court only has to be 'satisfied', whereas in patent opposition it has to be 'convinced'.

However, the fact that the patent will now be granted also means Genentech has the option of launching an infringement case if it wishes to do so.