Parsaclisib in Newly Diagnosed Stage I-IIIC Triple Negative or HER2+ Breast Cancer

Surgery and Treatment: Subjects must consent to having tissue collected for research purposes during a pre-treatment research biopsy, and scheduled surgery or end of treatment research biopsy prior to study entry. Prior to their scheduled standard of care surgery or research biopsy, subjects (n = 5 per dosing cohort) will be given oral doses of parsaclisib (10, 3.0 or 1.0 mg) once daily over 14 consecutive days. Cohorts will be enrolled sequentially by dose, where the cohort with the highest dose will be enrolled first and then the next cohort with the next highest dose will be enrolled after the enrollment of the prior cohort completes. At each dose level it will be determined whether either a 50% increase in the intratumoral CD8+ T cells/regulatory T- cell ratio or a 50% decrease in the intratumoral percentage of regulatory T cells is observed in at least 3 subjects out of 5 at that dose level. If this criterion is met, enrollment in the next highest dose level will commence. This procedure will be repeated until either this criterion is met at the lowest dose level, or when the criterion is not satisfied in a particular dose level. In the latter case, the next highest dose level will be chosen as the "minimum effective dose". In the former case, the lowest dose level will be chosen as the minimum effective dose. The doses being administered are lower than the therapeutic dose levels of parsaclisib (i.e., 20 to 30 mg once daily) recommended for subjects with lymphoma. If the criterion is not met in the first (highest) dose level, then the investigators assume the minimum effective dose is the therapeutic dose of parsaclisib (20 mg once daily) and the study will be terminated. Blood samples will be collected prior to parsaclisib treatment for research purposes. Subjects will undergo their standard of care surgical procedure or research biopsy within 72 hours (preferably within 24 hours) of completing drug treatment. Tissue and blood samples will be collected for correlative studies during surgery or during a research biopsy procedure. Subjects who have at least 7 days of parsaclisib treatment will be considered evaluable and may have tissue collected even if they have not completed the entire 14 day treatment regimen. Duration of Follow Up: Subjects will be followed post-operatively as per routine standard of care. Contraceptive use should continue for 93 days after the last dose of study drug administration. Subjects removed from study treatment for unacceptable adverse events will be followed until resolution or stabilization of the adverse event. Monitoring for AEs should continue for at least 30 days after the last dose of parsaclisib is administered. AEs related to therapy will then be followed until resolution to grade ≤1, or until the condition has stabilized with no further change expected.