Nab-Sirolimus and Endocrine Therapy in Recurrent Low Grade Serous Ovarian Cancer (NARETO)

This single arm phase II study proposes to evaluate the efficacy and safety of nab-sirolimus + endocrine therapy (Fulvestrant) in patients with recurrent low grade serous ovarian cancer (LGSOC).

Inclusion Criteria: 1. Patients must have a histologic confirmed low-grade serous ovarian cancer with clinical evidence of reoccurrence. 2. All patients must have measurable disease as defined by RECIST version 1.1. 3. ECOG Performance status must be 0-1. 4. Adequate bone marrow, hepatic and renal function as defined by the protocol. 5. At least 4 weeks must have elapsed since the patient underwent any major surgery. 6. At least 2 weeks must have elapsed since the patient received any radiation therapy. 7. Patients must have signed an IRN approved informed consent and authorization permitting release of personal health information. 8. All patients must be at least 18 years of age. 9. Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. 10. Patients of childbearing potential must have a negative serum pregnancy test prior to the study entry and be practicing a highly effective form of contraception. During the study treatment and for 12 weeks after stopping nab-sirolimus and 12 months after stopping Fulvestrant. Highly effective contraceptive methods include combination of any two of the following as defined in the protocol. Exclusion Criteria: 1. Patients who have previously received nab-sirolimus, any other mTOR inhibitor or any agent targeting the PI3K/AKT/mTOR pathway. (Prior MEKi is not exclusionary; up to one prior cytotoxic therapy is permissible.) 2. Known intolerance or hypersensitivity to nab-sirolimus or other rapamycin analogs (e.g. sirolimus, temsirolimus). 3. Patients receiving chronic treatment with systemic steroids or another immunosuppressive agent if \>10 mg prednisone equivalent per day 4. Patients with active or uncontrolled systemic infection requiring IV antibiotics, either ongoing or completed ≤7 days prior to enrollment. 5. Known severely impaired lung function, including: * CTCAE grade 2 (or greater) hypoxia (decreased oxygen saturation with exercise \[e.g., pulse oximeter \