Pfiz­er is end­ing the de­vel­op­ment of its po­ten­tial once-dai­ly pill treat­ment for obe­si­ty be­fore ven­tur­ing in­to the biggest and most ex­pen­sive lev­el of clin­i­cal test­ing.

The drug­mak­er said Tues­day that it would stop study­ing danuglipron af­ter a par­tic­i­pant in one of its tri­als ex­pe­ri­enced a pos­si­ble drug-in­duced liv­er in­jury that end­ed once the per­son stopped tak­ing the treat­ment.

The once-dai­ly ver­sion of the pill was in ear­ly-stage test­ing, with re­searchers try­ing to fig­ure out the best dose for pa­tients, a spokes­woman said. The com­pa­ny in­tend­ed to move the drug in­to late-stage test­ing, which is gen­er­al­ly the last phase of de­vel­op­ment be­fore a com­pa­ny sub­mits the po­ten­tial treat­ment to gov­ern­ment reg­u­la­tors for ap­proval.

A com­pa­ny of­fi­cial said in a state­ment that Pfiz­er still plans to de­vel­op oth­er po­ten­tial obe­si­ty treat­ments in ear­li­er stages of test­ing.

Obe­si­ty treat­ments have be­come one of the more promis­ing and lu­cra­tive sec­tors of drug de­vel­op­ment for phar­ma­ceu­ti­cal com­pa­nies. Eli Lil­ly and Co.’s Zep­bound, for in­stance, brought in near­ly $5 bil­lion in sales in 2024, its first full year on the mar­ket.

But lead­ing treat­ments like Zep­bound and No­vo Nordisk’s We­govy are in­jectable. Drug­mak­ers are ea­ger to de­vel­op an eas­i­er-to-take pill ver­sion for pa­tients who don’t want to deal with nee­dles and dai­ly in­jec­tions.

Lil­ly re­searchers ex­pect to see da­ta this year from stud­ies of a cou­ple po­ten­tial oral treat­ments it has de­vel­oped.

While the drugs have be­come top-sell­ers, many pa­tients have had a hard time get­ting them ei­ther due to re­cent­ly con­clud­ed short­ages or patchy in­sur­ance cov­er­age. Both Lil­ly and No­vo have re­cent­ly an­nounced price cuts, but the treat­ments can still cost hun­dreds of dol­lars a month, putting them out of reach for some peo­ple with­out cov­er­age.

Pfiz­er said in late 2023 that it would aban­don a twice-dai­ly ver­sion of danuglipron that had adavnced to mid-stage test­ing af­ter more than half the pa­tients in a clin­i­cal tri­al stopped tak­ing it.

A com­pa­ny spokes­woman said the de­ci­sion an­nounced Mon­day meant Pfiz­er would al­so stop test­ing danuglipron in com­bi­na­tion with oth­er drugs to treat obe­si­ty.

Shares of New York-based Pfiz­er Inc. ad­vanced 12 cents to $22.03 in morn­ing trad­ing Mon­day.