Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of PN-881 in Healthy Subjects.

Inclusion Criteria: 1. Healthy male and female participants of non-childbearing potential, aged 18-65 years inclusive 2. Body mass index (BMI) between 18 and 32 kg/m² (inclusive) at screening 3. Willing and able to comply with all study requirements and provide written informed consent 4. Male participants with female partners of childbearing potential must agree to use highly effective contraception during the study and for 90 days after the last dose Exclusion Criteria: 1. Clinically significant history or presence of cardiovascular, gastrointestinal, hepatic, renal, neurological, psychiatric, or allergic diseases 2. History of neoplastic disease (except adequately treated non-melanoma skin cancer) 3. Positive test for hepatitis B, hepatitis C, or HIV at screening 4. History of substance abuse or recreational IV drug use within the past 2 years 5. Clinically significant infection or fever (\>38°C) within 2 weeks prior to screening 6. Use of any prescription/non-prescription drugs or herbal supplements within 7 days or 5 half-lives before dosing (unless approved by investigator) 7. Supine blood pressure or ECG abnormalities outside protocol-defined ranges 8. Use of tobacco/nicotine products exceeding 5 cigarettes/day or 2 chews/day 9. Consumption of \>21 alcohol units/week (males) or \>14 units/week (females)