A Study to Learn About the Study Medicine Called PF-07258669 in Older Adults Including Those at Risk of Malnutrition

The purpose of this study is to look at safety, tolerability, and pharmacodynamic effects (i.e. how the study drug affects your body) of PF-07258669 in older participants ((60 years to \<90 years) including those at risk of malnutrition. The study medicine PF-07258669 is being developed for the treatment of unintended weight loss in older adults. People with this condition have decreased appetite and food intake, which is an important reason for poor nutrition and health results in people with unintended weight loss. This is approximately a 26-week-long study with 9 visits to the study doctor and 4 telehealth visits (ie. visits by phone call). The study will include * Screening period for up to 4 weeks * Pre-treatment period of 2 weeks * Treatment period of 16 weeks : study drug (PF-07258669 or matching placebo) * Follow-up period of 4 weeks The study requires answering questionnaires and use of digital devices at home to measure blood pressure and physical activity. The study team will monitor how each participant is doing during the study