Shares in Pfizer (NYSE:PFE) slumped in early trading on Friday after the drugmaker said that the twice-daily form of its new oral obesity treatment will not advance into late-stage studies.

In a statement, Pfizer said that the drug candidate, danuglipron, demonstrated “statistically significant” weight loss of as much as 13% at 32 weeks in the study’s participants.

But data from the phase two trial of the drug showed that mild gastrointestinal side effects were seen at a “high rate” in patients using the medication, Pfizer added. Discontinuation rates were subsequently “greater than 50%,” it noted.

As a result, the company said that any future development of danuglipron would be focused on its once-daily oral pill. Data on this formulation is expected to be unveiled in the first half of next year.

Pharmaceutical firms have been racing to secure a cheap, oral obesity drug, particularly after the soaring popularity of a weight-loss injection from Danish group Novo Nordisk (NYSE:NVO). According to Morgan Stanley, growing demand for these treatments could push the value of the global obesity drug market up from $2.4 billion in 2022 to $77 billion in 2030.