Sapanisertib and Serabelisib (PIKTOR) With Paclitaxel and a Substudy With an Insulin-Suppressing Diet in Patients With Advanced/Recurrent Endometrial Cancer

Inclusion Criteria: * Histologically confirmed diagnosis of endometrioid endometrial carcinoma. * Documented evidence of advanced or recurrent endometrial cancer that is not amenable to surgery/radiation for curative intent. * Participant has received at least 1 but not more than 4 prior systemic therapies. Prior therapy must include platinum-based chemotherapy and a checkpoint inhibitor, either separately or in combination. If a subject has been unable to be treated with checkpoint inhibitor in the past due to medical contraindications, consult with Medical Monitor. * PI3K/AKT/mTOR pathway gene alteration identified. * At least 1 measurable target lesion according to RECIST v1.1 * Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1 at Screening. * Non-pregnant, non-lactating females who are postmenopausal, surgically sterile or who agree to use effective contraceptive methods.. Exclusion Criteria: * Participants with central nervous system metastases are not eligible, unless they have completed local therapy and have discontinued the use of corticosteroids for this indication for at least 4 weeks before starting treatment in this study * Active malignancy (except for endometrial cancer, definitively treated in-situ carcinomas \[e.g., breast, cervix, bladder\], or basal or squamous cell carcinoma of the skin) within the past 24 months prior to treatment. Fully resected localized malignancies are eligible. * Gastric feeding tube (gastrostomy tube), gastroint…