Novartis AG’s profit fell more than estimated and sales unexpectedly declined in the first quarter as some of the drugmaker’s best-selling medicines were hit hard by generic competition.

Core operating profit dropped 12% to $4.9 billion, Novartis said TuesdayBloomberg Terminal. Analysts surveyed by Bloomberg estimated earnings of $5.18 billion. Revenue showed the first decrease in almost two years, according to Bloomberg data.