A Phase I open label, dose-escalation and expansion study to evaluate the safety, tolerability, pharmacokinetics and antitumor activity of AK137 in patients with advanced malignant tumors.

Inclusion Criteria:

1. Written and signed informed consent.
2. Eastern Cooperative Oncology Group (ECOG) Performance Score of 0 or 1.
3. Life expectancy ≥3 months.
4. Histologically or cytologically documented unresectable advanced or metastatic malignant tumor that has failed or intolerant of standard therapy, or for which no effective standard therapy is available.
5. Subject must have at least one measurable lesion according to RECIST Version1.1.
6. Adequate organ function.

Exclusion Criteria:

1. Any malignancy other than the disease under study within the past 3 years except for radically cured local cancers, such as basal cell skin cancer, carcinoma in situ of the cervix, or carcinoma in situ of breast.
2. Receipt of any anti-CD73, anti-LAG-3 treatment.
3. Experienced a toxicity that led to the permanent discontinuation of prior immunotherapy. All adverse events (AEs) while receiving prior immunotherapy have not completely resolved or resolved to Grade 1 prior to screening. Additionally, the use of immunosuppression other than corticosteroids was required.
4. Unresolved toxicities from prior anticancer therapy, defined as not having resolved to NCI CTCAE v5.0 Grade 0 or 1, or to levels specified in the inclusion/exclusion criteria, except for toxicities not considered a safety risk (e.g., alopecia, neuropathy, or asymptomatic laboratory abnormalities).
5. Major surgical procedure within 4 weeks prior to the first dose of AK137 or still recovering from prior surgery.
6. History of organ transplant.
7. Known allergy or reaction to any component of the AK137 formulation. History of severe hypersensitivity reactions to other mAbs.