A Study to Evaluate the Safety and Efficacy of A2B694, a Logic-gated CAR T, in Participants with Solid Tumors That Express MSLN and Have Lost HLA-A*02 Expression

Inclusion Criteria:

Key Inclusion Criteria:

1. Appropriately enrolled in the BASECAMP-1 A2 Biotherapeutics, Inc. study, with tissuedemonstrating LOH of HLA-A*02 by NGS (whenever possible from the primary site),successful apheresis and PBMC processing, and with sufficient stored cells availablefor Tmod CAR T-cell therapy

2. Histologically confirmed recurrent unresectable, locally advanced, or metastaticCRC, NSCLC, PANC, OVCA, MESO, or other solid tumors with MSLN expression. Measurabledisease is required with lesions of >1.0 cm by CT.

3. Received previous required therapy for the appropriate solid tumor disease asdescribed in the protocol

4. Has adequate organ function as described in the protocol

5. ECOG performance status of 0 to 1

6. Life expectancy of ≥3 months

7. Willing to comply with study schedule of assessments including long term safetyfollow up

Key Exclusion Criteria:

1. Has disease that is suitable for local therapy or able to receive standard of caretherapy that is therapeutic and not palliative

2. Prior allogeneic stem cell transplant

3. Prior solid organ transplant

4. MESO with pleural involvement extending into the peritoneum

5. Cancer therapy within 3 weeks or 3 half lives of A2B694 infusion

6. Radiotherapy within 28 days of A2B694 infusion

7. Unstable angina, arrhythmia, myocardial infarction, or any other significant cardiacdisease within the last 6 months

8. Any new symptomatic pulmonary embolism (PE) or a deep vein thrombosis (DVT) within 3months of enrollment. Therapeutic dosing of anticoagulants is allowed for history ofPE or DVT if greater than 3 months from time of enrollment, and adequately treated

9. History of interstitial lung disease including drug-induced interstitial lungdisease and radiation pneumonitis that requires treatment with prolonged steroids orother immune suppressive agents within 1 year

10. Requires supplemental home oxygen

11. Females of childbearing potential who are pregnant or breastfeeding

12. Subjects, both male and female, of childbearing potential who are not willing topractice birth control from the time of consent through 6 months post infusion ofA2B694