Phase 1 Study of 6MW5311 in Adults With Relapsed or Refractory Blood Cancers

To assess safety and tolerability at increasing dose levels of 6MW5311 in successive cohorts of participants with MM, AML and CMML in order to estimate the maximum tolerated dose (MTD) and select the recommended Phase 2 dose (RP2D) or the recommended expansion dose (RED).

Inclusion Criteria: 1. Age 18 years or older at the time of signing the informed consent form; male or female. 2. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 for the dose-escalation part, or 0 to 2 for the dose-expansion part. 3. Life expectancy greater than 3 months. 4. Multiple myeloma (MM): histologically and/or cytologically confirmed MM per International Myeloma Working Group (IMWG) 2016 criteria, with at least 3 prior lines of MM therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody. * Chronic myelomonocytic leukemia (CMML): morphologically confirmed by bone marrow examination per World Health Organization (WHO) 2016 classification, with relapsed disease or failure of prior therapy. * Acute myeloid leukemia (AML; dose-expansion part only): morphologically confirmed acute myelomonocytic leukemia or acute monocytic leukemia per WHO 2016 classification, meeting the protocol definition of relapsed or refractory AML. 5. MM only: measurable disease at screening. 6. Adequate hematologic function at screening: 7. Able to understand and comply with the protocol requirements, willing to participate in the clinical study, and able to provide written informed consent. Exclusion Criteria: * 1\. AML and CMML only: any other anticancer therapy within 2 weeks before the first dose of study drug. MM only: prior anticancer therapy within the following intervals before the first dose of study drug: * small-molecule targeted therapy within 4 weeks or 5 half-lives, whichever is shorter; * antibody therapy within 3 weeks; * cytotoxic chemotherapy, proteasome inhibitor therapy, or traditional Chinese medicine (including Chinese patent medicine) with an anticancer indication within 2 weeks; * immunomodulatory agent within 1 week; * chimeric antigen receptor T-cell (CAR-T) therapy within 3 months; * radiotherapy within 1 week. 2. Receipt of any other investigational drug within 4 weeks before the first dose of study drug. 3\. Prior allogeneic stem cell transplant; or autologous stem cell transplant within 3 months before the first dose of study drug. 4\. Planned stem cell transplant during the study. 5. Prior treatment with a LILRB4-targeted therapy.