A First-In-Human Phase 1 Trial of T-Cell Membrane-Anchored Tumor Targeted Il12 (Attil12)- T-Cell Therapy in Subjects With Advanced/Metastatic Soft Tissue and Bone Sarcoma

Inclusion criteria:

1. Age ≥12 years old

2. Histologically-confirmed locally advanced or metastatic soft tissue or bone sarcoma

3. Osteosarcoma expansion cohort: histologically confirmed unresectablerecurrent/metastatic osteosarcoma

4. Evaluable disease.

5. Participants must have received at least 1 prior line of systemic therapy for thetreatment of sarcoma, unless no standard therapy exists for a specific sarcomasubtype

6. At least 3 weeks must have elapsed since the last cytotoxic chemotherapy orimmunotherapy prior to leukapheresis/PBMC collection. For targeted therapies, atleast 4 half-lives or 3 weeks must have elapsed prior to leukapheresis (whichever isshorter).

7. Standard of care anti-cancer therapy will be permitted following leukapheresis butprior to initiation of cyclophosphamide such that at least 3 weeks must have elapsedsince last cytotoxic chemotherapy or immunotherapy prior to starting treatment withcyclophosphamide. For targeted therapies, at least 4 half-lives or 3 weeks must haveelapsed prior to initiation of treatment with cyclophosphamide (whichever isshorter). Investigational anti-cancer therapy will not be permitted.

8. ECOG performance status of 0 or 1 (Performance level as measured by Karnofsky forpatients ≥16 years of age or Lansky for patients < 16 years of age, see Appendix B)

9. Participants must be willing to undergo core-needle biopsy

10. Participants must have organ and marrow function as defined below

11. Absolute neutrophil count (ANC) ≥ 1 K/uL, Hemoglobin ≥ 9 g/dL, Platelets≥100 K/mm3

12. Serum creatinine ≤ 2 mg/dL OR creatinine clearance > 50 mL/min

13. Aspartic transaminase (AST) ≤ 1.5 x upper limit of normal (ULN), Alaninetransaminase (ALT) ≤ 1.5 x ULN, Bilirubin ≤ 1.5 x ULN

14. Women of childbearing potential (WOCBP) must agree to use method(s) ofcontraception: at least one highly effective or two effective accepted methods ofcontraception to avoid conception throughout the study in such a manner that therisk of pregnancy is minimized. Suggested precautions should be used to minimize therisk or pregnancy for at least 1 month before start of therapy, and while women areon study for up to 3 months after T cell infusion. WOCBP include any female who hasexperienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation or bilateral oophorectomy) or is notpostmenopausal

15. Men must be willing and able to use an acceptable method of birth control such aslatex condom during the dosing period and for at least 3 months after completion ofthe study agent administration (T cell infusion) if their sexual partners are WOCBP.

16. Signed Informed Consent and if applicable, pediatric assent

Exclusion criteria:

1. Known sensitivity to cyclophosphamide and/or study agents Active or prior documentedautoimmune disease (including inflammatory bowel disease, celiac disease, Wegenersyndrome) within the past 2 years. Participants with childhood atopy or asthma,vitiligo, alopecia, Hashimoto syndrome, Grave's disease, or psoriasis not requiringsystemic treatment (within the past 2 years) are not excluded

2. Untreated central nervous system metastatic disease, leptomeningeal disease, or cordcompression. Participants previously treated central nervous system metastases thatare radiographically and neurologically stable for at least 6 weeks and do notrequire corticosteroids (of any dose) for symptomatic management for at least 14days prior to first dose of attIL12-T cells are permitted to enroll.

3. Any concurrent chemotherapy, immunotherapy, or biologic or hormonal therapy forcancer treatment at the time of leukapheresis or attIL12 T cell infusion . Standardof care anti-cancer therapy will be permitted following leukapheresis but prior toinitiation of cyclophosphamide as bridging therapy (per section 12.4.1). Concurrentuse of hormones for non-cancer-related conditions (eg, insulin for diabetes andhormone replacement therapy) is acceptable. In addition, local treatment (eg, bylocal surgery, radiotherapy, or ablation) of isolated lesions for palliative intentis acceptable beyond 30 days following attIL12 T cell administration with priorconsultation and in agreement with the PI.

4. Unresolved toxicities from prior anticancer therapy, defined as having not resolvedto NCI CTCAE v5 Grade 0 or 1 with the exception of alopecia and laboratory valueslisted per the inclusion criteria. Participants with irreversible toxicity that isnot reasonably expected to be exacerbated by any of the investigational products maybe included (eg, hearing loss) after consultation with the PI.

5. History of primary immunodeficiency, solid organ transplantation, or previousclinical diagnosis of tuberculosis.

6. Receipt of live, attenuated vaccine within 28 days prior to the first dose ofinvestigational products

7. Major surgery (as defined by the investigator) within 4 weeks prior to first dose oftreatment or if still recovering from prior surgery. Biopsy as per study protocol isallowed

8. Uncontrolled intercurrent illness including, but not limited to, ongoing or activeinfection, symptomatic congestive heart failure, uncontrolled hypertension, unstableangina pectoris, cardiac arrhythmia, active peptic ulcer disease or gastritis, orpsychiatric illness/social situations that would limit compliance with studyrequirement, substantially increase risk of incurring Aes from the study agents, orcompromise the ability of the subject to give written informed consent.

9. Participants with cognitive impairment, including adults with cognitive impairmentsuch as trisomy 21 or similar conditions are not specifically excluded fromparticipation, such that appropriate written informed consent is obtained from theparent or legal guardian and they are able to complete with the study protocolrequirements and treatment.

10. Active concurrent second malignancy

11. Pregnant or lactating women

12. Any positive test result for hepatitis B or C virus indicating acute or chronicinfection

13. Known history of testing positive for human immunodeficiency virus or known acquiredimmunodeficiency syndrome