European regulators will seek outside advice before making a decision on approval of Eisai and Biogen’s Leqembi medicine for Alzheimer’s disease.

The Committee for Medicinal Products for Human Use opted to convene a meeting of a scientific advisory group, which should take place before the end of March, the Japanese drugmaker said Thursday. Much like Food and Drug Administration advisory committees, the panels are made up of independent advisers who can offer insight into specific scientific or technical issues.

It’s unclear what prompted the regulatory committee to call on its advisory group, but the move likely means a delay for Eisai’s application. In November, the company told investors to expect a decision from the European Commission by March. Now, Eisai anticipates a decision by the end of June.

The European Union represents the next major target for the drug, which is already approved in the two biggest markets, the U.S. and China. Leqembi won clearance in China just this week. In the U.S., Eisai and partner Biogen hoped to have 10,000 patients on the medication before April, but that target now looks harder to achieve.

Though the drug’s launch has been smoother than the rollout of Biogen’s earlier Alzheimer’s disease drug Aduhelm, the companies are still encountering challenges. They have overcome an initially restrictive U.S. government policy on reimbursement and now are confronting long waits for patients trying to get appointments with neurologists so they can access treatment.

Biogen CEO Christopher Viehbacher this week pointed to promising numbers from centers ordering the drug and told investors that January sales would be a key barometer to measure the product’s progress.