European regulators have stuck by their decision to notrecommend Merck Serono’s multiple sclerosis drug cladribine.

The final decision by the European Medicines Agency’sCommittee for Medicinal Products for Human Use confirms its previous negativeopinion of the drug announced back in September, which lead to Merck appealingthat decision and requesting a re-examination.

However, the majority of the Committee, on re-evaluation,were still of the opinion that the benefits of cladribine did not outweigh therisks based on the data submitted. This was despite some members voting infavour of a conditional marketing authorisation.

“We are disappointed by the CHMP opinion however we continueto believe that our data support Cladribine Tablets as a treatment option forpatients with relapsing forms of MS,” said Dr Bernhard Kirschbaum, MerckSerono’s head of research and development. “We remain fully committed to thepotential of Cladribine Tablets to meet an unmet medical need as an oral,short-course, disease-modifying drug for multiple sclerosis and will evaluateour options for bringing this therapeutic option to patients who could benefitfrom it also in Europe.”

The company said it would complete the ongoing clinicaltrials, which will provide additional information on the efficacy and safety ofCladribine Tablets in MS. Results from these trials are expected at the end ofthis year and the first half of 2012.

AstraZeneca responds to FDA

Meanwhile, in the USA, AstraZeneca has replied to the USFood and Drug Administration’s complete response letter regarding itsanticlotting drug Brilinta (ticagrelor).

In December last year, the anticipated positive decision forthe drug was denied after the regulators requested additional analyses of thePLATO data used in the submission.

While study results were positive, there had been concernsover variations in drug efficacy between countries, with a lack of benefit inthe North American subgroup.

In a statement, AstraZeneca said it believed thesesupplementary analyses support the hypothesis that the apparent difference intreatment effect observed in the US and non-US patient subsets is most likely areflection of an underlying interaction between ticagrelor and higher doses ofaspirin.

“AstraZeneca remains of the view that either the play ofchance or an interaction between high dose aspirin and ticagrelor are viableexplanations for the efficacy differences observed in a subset of US patientsin the PLATO trial… AstraZeneca remains confident in the New Drug Applicationsubmission for ticagrelor and will continue to work with the FDA to progresstowards the completion of the review.”

The FDA will now review the company’s response to determinewhether the information submitted is complete and whether to designate atwo-month review or a six-month review.