(Reuters) -Biogen on Tuesday forecast flat 2024 product revenue as top-selling drugs face tough competition and sales of newer treatments take off slowly, but said there are signs its new Alzheimer's drug is gaining traction. Shares of the U.S. biotech fell 7% as it missed Wall Street expectations for quarterly revenue and projected sales for this year that several analysts found underwhelming. Sales of pricey spinal muscular atrophy drug Spinraza, which is dealing with fresh competition, also missed estimates.
Blood tests for Alzheimer's are needed to more widely diagnose the brain-wasting disease and understand its prevalence, but it will be another couple of years before they become an everyday tool, medical experts and company executives say. Blood testing is initially likely to be used to rule out Alzheimer's, with positive results signaling the need for more advanced diagnostics. Several Alzheimer's blood tests are in the works – and one is already being sold to consumers – but none have been established as accurate, formally approved by regulators or reimbursed by insurers.