Two of the biggest drug com­pa­nies in the world are prepar­ing for a multi­bil­lion-dol­lar show­down to buy Met­sera, af­ter No­vo Nordisk’s shock an­nounce­ment Thurs­day that it had of­fered $1.6 bil­lion more than Pfiz­er’s signed deal for the an­ti-obe­si­ty com­pa­ny.

Pfiz­er now has four busi­ness days — un­til Tues­day — to de­cide whether it wants to in­crease its of­fer, to try to block No­vo, or to find an­oth­er path back to a lead­ing po­si­tion in the race for a next-gen­er­a­tion an­ti-obe­si­ty drug.

Both com­pa­nies are pre­pared to bid more if need­ed, ac­cord­ing to peo­ple fa­mil­iar with the sit­u­a­tion who spoke on con­di­tion of anonymi­ty. And the stakes are huge. The weight loss drugs have be­come the fastest-sell­ing class of med­i­cine of all time, and they have pres­sured phar­ma com­pa­nies that have missed out or that will come late to the mar­ket.

No­vo Nordisk brought on Maziar Mike Doust­dar as CEO to make sweep­ing changes at the com­pa­ny, which is strug­gling to claw back the ground it's lost to Eli Lil­ly in the obe­si­ty mar­ket.

On Thurs­day, it be­came clear just how ag­gres­sive he is will­ing to be. By open­ing a bid­ding war with Pfiz­er for the obe­si­ty drug de­vel­op­er Met­sera, Doust­dar has re­versed No­vo’s pre­vi­ous de­ci­sion to back off from an ac­qui­si­tion of the biotech.

And he is fol­low­ing the same au­da­cious pat­tern he set with No­vo’s bid for MASH drug de­vel­op­er Akero Ther­a­peu­tics ear­li­er this month.

Led by Lars Fruer­gaard Jør­gensen at the time, No­vo made its first play for Met­sera in Jan­u­ary, of­fer­ing to buy the com­pa­ny for around $2 bil­lion. A few days lat­er, Met­sera re­ject­ed the bid, call­ing it “mean­ing­ful­ly in­suf­fi­cient with re­spect to both val­ue and clos­ing cer­tain­ty.”

Bris­tol My­ers Squibb didn’t re­veal any­thing earth-shat­ter­ing in its third-quar­ter earn­ings re­port on Thurs­day, but rather a hand­ful of small­er up­dates on its pipeline and ne­go­ti­a­tions with the Trump ad­min­is­tra­tion.

And an­a­lysts ap­peared most in­ter­est­ed in an up­com­ing read­out for Coben­fy in Alzheimer’s dis­ease psy­chosis — ex­pect­ed be­fore the end of the year — and ex­pressed a grow­ing lev­el of anx­i­ety. Ear­li­er this year, Coben­fy failed a Phase 3 study as an ad­junc­tive treat­ment for schiz­o­phre­nia, and for­mer CMO Samit Hi­rawat last quar­ter said the com­pa­ny would be con­duct­ing tri­al site re­views for the up­com­ing psy­chosis da­ta.

On Thurs­day’s call, CEO Chris Boern­er tried to as­suage con­cerns, re­it­er­at­ing that the da­ta are on track for the end of 2025. When asked, he de­clined to pro­vide specifics on why the da­ta haven’t come out yet and whether or not Bris­tol My­ers is see­ing any ir­reg­u­lar­i­ties at the tri­al sites un­der re­view.