M1001 is a weak agonist of HIF-2α, directly binds to the HIF-2α PAS-B domain, with a Kd of 667 nM. M1001 enhances the stabilities of HIF-2α-ARNT complex.
PT2399 is a potent and selective HIF-2α antagonist, which directly binds to HIF-2α PAS B domain with an IC50 of 6 nM. PT2399 displays potent antitumor activity in vivo.