Sirolimus Pre-conditioning on T Cell Activity and T-cell Engaging Bispecific Antibody Efficacy in Multiple Myeloma

Inclusion Criteria: To be eligible to participate in this study, an individual must meet all of the following criteria: * Willingness and ability to provide signed and dated informed consent form. * Stated willingness to comply with all study procedures and availability for the duration of the study. * Aged 18 years of older. * Diagnosis with multiple myeloma, per IMWG Consensus Criteria.20 * Planned for treatment with teclistamab, or talquetamab per standard of care, label indications.15 * Prior exposure to any of the following types of T-cell engaging therapies. 1. Anti-BCMA x CD3 bispecific antibody (for example: teclistamab, elranatamab) 2. Anti-GPRC5d x CD3 bispecific antibody (for example: talquetamab) 3. Anti-GPRC5d x CD3 x CD38 trispecific antibody 4. Anti-BCMA x CD3 x CD38 trispecific antibody 5. Anti-BCMA x CD3 x GPRC5d trispecific antibody 6. Anti-BCMA chimeric antigen T-cell (for example: idecabtagene vicleucel, ciltacabtagene autoleucel) 7. Anti-FcRL5 x CD3 bispecific antibody * Required clinical laboratory values during screening phase Hematologic Parameters Hemoglobin ≥7.0 g/dL; Platelets ≥25 x 109/L; Absolute Lymphocyte Count ≥0.2 x 109/L Chemistries AST/ALT \< 5 x the ULN; Total Bilirubin \< 3 x the ULN * Ability to take oral medication and be willing to adhere to the sirolimus pre-conditioning regimen. * ECOG performance status of 0, 1, or 2 (KPS of \>50). * For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner per section5.3. * Agreement to adhere to Lifestyle Considerations (see section 5.3) throughout study duration. Exclusion Criteria: An individual who meets any of the following criteria will be excluded from participation in this study: * Participants whose multiple myeloma is progressing at a rapid pace requiring immediate anti-myeloma therapy per assessment by the principal investigator or enrolling investigator are excluded. * Excluded concomitant medication exposures: * Exposure to corticosteroids within 1 week of treatment start * Exposure to calcineurin inhibitor or mTOR inhibitors (tacrolimus, everolimus, temsirolimus, sirolimus) * Immunomodulatory monoclonal antibodies targeting tumor necrosis factor alpha (e.g. infliximab), interleukin 6 (e.g. siltuximab), * Janus kinase inhibitors (e.g. ruxolitinib) * Any other investigational drug within 28 days * History of allogeneic hematopoietic cell transplantation. * Excluded concurrent medical conditions: * Active uncontrolled infection within 7 days prior to treatment start * Uncontrolled thrombotic event within 3 months of treatment start * Acute myocardial infarction or acute coronary syndrome within 6 months of start of treatment * Uncontrolled inflammatory bowel disease * Active hepatitis B virus, hepatitis C virus, or Human Immunodeficiency Virus infection * Uncontrolled rheumatologic conditions * Use of ACE-inhibitor therapy within 1 week of treatment start * Patients found to be taking ace-inhibitor therapy during screening can be included if the ace-inhibitor is substituted for an angiotensin receptor blocking agent. (https://drug-interactions.medicine.iu.edu/main-table) * CYP3A4/p-gp inhibitors and inducers for 7 days prior to sirolimus doses and 7 days after sirolimus doses(see appendix A for list) * Any other current active malignancy or history of metastatic malignancy that has the potential to interfere with the safety or efficacy assessment of the investigational intervention * Pregnancy or lactation. * Known allergic reactions to study agent (sirolimus).