Insulin giant Novo Nordisk (NYSE:NVO) has reportedly approached Global Blood Therapeutics (NSDQ:GBT) to discuss a possible takeover.

The U.S. biotech is reviewing its options with an investment bank, according to Reuters, and there is no guarantee that it will enter formal negotiations with Novo Nordisk.

Global Blood Therapeutics is developing GBT440, a once-daily, oral therapy to treat patients with sickle cell disease. GBT440 targets abnormal polymerization of deoxy-hemoglobin, the underlying mechanism of red blood cell sickling, according to Global Blood Therapeutics.

The company is investigating its treatment in a Phase 1/2 study with healthy and sickle cell disease patients.

GBT shares were trading at $33.45 apiece in mid-morning activity, up 18.2%.

In February, shares in Novo Nordisk fell -9% after the pharmaceutical company missed expectations on Wall Street with its 4th quarter results and lowered its outlook for 2017.

The Danish company posted profits of 8.7 billion Danish kroner, or $1.26 billion USD, on sales of 29.57 billion kroner for the 3 months ended Dec. 31, for bottom-line growth of 5% compared with the same period last year.

Adjusted to exclude 1-time items, EPS were 3.45 kroner, 2% lower than the consensus on The Street.

Nordisk and other insulin makers have been under increased pressure this year, as the companies have been repeatedly called out for price hikes.

In February this year, a class-action lawsuit was filed in the U.S. District Court of Massachusetts, alleging that insulin makers Sanofi (NYSE:SNY), Nordisk and Eli Lilly (NYSE:LLY) conspired to raise their list prices to get access to pharmacy benefit managers’ preferred lists, instead of competing with each other based on real market prices.

In the last 5 years, the 3 companies have raised the sticker prices on their drugs by more than 150%, according to the lawsuit. A recent study by the American Medical Association demonstrated that the price of insulin nearly tripled between 2002 and 2013.