Study to Assess the Safety, Tolerability, PK, ECG Effects, Food Effect, and Drug-drug Interaction (DDI) of Hormonal Contraceptives of PTI-428 in Healthy Female Volunteers

This trial will consist of three parts: the first two parts will enroll healthy female volunteers into a single ascending dose (SAD) and multiple ascending dose (MAD) treatment groups. The SAD treatment group is comprised of at least 3 cohorts where subjects will be randomized to a single dose of either PTI-428 or placebo and will be followed for 7 days post dose. A total of 24 subjects are anticipated to participate in this part of the study. Following the conclusion of the respective SAD level dose groups and after sufficient review of study data and approval by the SRC, a second set of healthy adult female subjects will participate in an assigned MAD treatment group. The MAD treatment group is comprised of 3 cohorts where subjects will be randomized to either PTI-428 or placebo and will be followed for a total of 14 days. The SRC will convene after the completion of each cohort to evaluate safety, PK and other relevant data. The SRC will determine whether to proceed to the next planned dose level, to reduce the dose, or to stop the study. The next cohort may commence only after written SRC approval. A total of 24 subjects are anticipated to participate in this part of the study. Following completion of the SAD and MAD, 40 female healthy volunteers will participate in two treatment periods of the DDI study component: Treatment period A will consist of once daily oral contraceptive (OC) for 28-days (21-day hormonal active + 7 days off). Treatment period B will randomize subjects to PTI-428 or placebo in combination with once daily OC for 28 days (21-day hormonal active and PTI-428 or placebo + 7 days off). Following completion of the subjects' second treatment period, they will be followed for 7-days after their last dose.