A Study to Learn How Different Amounts of the Study Medicine Called PF-07985631 Are Tolerated and Act in the Body in Healthy Adults

The purpose of this study is to learn about the safety and effects of the study medicine (called PF-07985631) for the possible treatment of a kidney disease called IgA nephropathy. This study is seeking participants who * are male or female between 18 and 45 years of age (55 for Japanese/Chinese/multiple dose participants) * are deemed to be healthy Participants in this study will receive PF-07985631 or placebo. A placebo does not have any medicine in it but looks just like the medicine being studied. PF-07985631 or placebo will be given as a small needle injection (in the abdomen, thigh or back of the arm) at the study clinic. Most participants will receive PF-07985631 or placebo one time. Some participants may receive PF-07985631 or placebo twice. The study will compare the experiences of people receiving PF-07985631 to those of the people who do not. This will help decide if PF-07985631 is safe and effective. Participants who take PF-07985631 or placebo will take part in this study for about four- four and a half months. During this time, they will stay at the study clinic for 12 to 19 days and will have 7 more study visits at the study clinic. During study clinic stays and study visits, blood samples will be done and safety reviews completed.