Novo Nordisk shares rallied on Tuesday as a maker of a weight-loss drug alternative confirmed it won’t be selling it for much longer.

Investors are scrambling to adjust, after the telehealth specialist Hims & Hers said it would stop selling an alternative to Novo Nordisk's Wegovy and Ozempic weight-loss drugs. Hims stock stood about 17% lower at under $42.

Few big pharma stocks have been bigger winners over the last three years than Eli Lilly and Novo Nordisk. Lilly now ranks as the largest drugmaker in the world, with a market cap of $844 billion, after its shares skyrocketed more than 270%. Novo Nordisk stock is up around 75% despite a pullback in recent months.

After the FDA removed semaglutide injection products from a shortage list, compounders like Hims have 60-90 days to stop making copies.