Study to Evaluate VT3989 in Patients with Metastatic Solid Tumors

Inclusion Criteria:

• Part 1: pathologically diagnosed metastatic solid tumor or mesothelioma that hasprogressed on or after all approved therapies of known clinical benefit except ifthe patient refuses or is not a candidate for such therapy;

• Part 2 Expansion Cohorts 1 and 2: in mesothelioma cohorts, pathologically diagnosedadvanced malignant mesothelioma with or without NF2 mutations, that has progressedon or after all approved therapies of known clinical benefit except if the patientrefuses or is not a candidate for such therapy.

• Part 2 Expansion Cohort 3: non-pleural mesothelioma patients with epithelioidhistology, relapsed from or refractory to prior platinum-based chemotherapy andimmunotherapy.

• Part 2 Expansion Cohort 4: in the solid tumor cohort, pathologically diagnosedmetastatic or locally advanced solid tumor with clearly inactivating NF2mutations/alterations or YAP/TAZ gene rearrangements, which have progressed on orafter approved therapies of known clinical benefit except if the patient refuses oris not a candidate for such therapy.

• Part 2 Expansion Cohort 5: pathologically diagnosed advanced malignant pleuralmesothelioma with epithelioid histology, that has progressed on or after licensedimmunotherapy, chemotherapy or combined chemoimmunotherapy except if the patientrefuses or is not a candidate for such therapy.

• Part 3 Combination Cohort A: pathologically diagnosed, metastatic or unresectablemalignant mesothelioma including both pleural and non-pleural) patients who have notreceived systemic therapy.

• Part 3 Combination Cohort B: pathologically diagnosed incurable locally advanced (inoperable or recurrent), or metastatic NSCLC with exon 19 deletions or exon 21L858R mutations, with or without prior treatment with Osimertinib.

• Part 1: evaluable or measurable disease per RECIST v1.1 or mRECIST

• Part 2 and 3: measurable disease per RECIST v1.1 for non-pleural mesothelioma orother solid tumors or modified RECIST v1.1 for malignant pleural mesothelioma.mRECIST may be used for pleural extension of non-pleural mesothelioma or for mixedpleural and peritoneal (or other) mesothelioma.

• ECOG: 0-1

• Adequate organ functions, including the liver, kidneys, and hematopoietic system

Exclusion Criteria:

• Active brain metastases or primary CNS (central nervous system) tumors.

• History of leptomeningeal metastases

• Active or chronic, uncontrolled bacterial, viral, or fungal infection(s) requiringsystemic therapy

• Known HIV positive or active Hepatitis B or Hepatitis C

• Clinically significant cardiovascular disease

• Corrected QT (QTcF) interval > 470 msec (using Fridericia's correction formula);except for Part 2 Expansion Cohort 3, the QTcF interval criteria is > 450 msec)

• Additional active malignancy that may confound the assessment of the study endpoints

• Women who are pregnant or breastfeeding

• Prior treatment with TEAD inhibitor, except for EHE patients