The objective of this study is to evaluate the safety, tolerability and PK profile of HMPL-415S1 and determine MTD and/or RP2D in patients with advanced malignant solid tumor.

This study is expected to enroll 36-81 patients, including 26-66 patients for dose escalation, additional 10-15 patients will be enrolled at the dose level of determined RP2D.

Inclusion Criteria:

All the following conditions must be met for enrollment:

1. Fully understand this study and voluntarily sign the ICF;
2. Dose escalation Patients with advanced malignant solid tumor confirmed by histopathology or cytology, who have failed, been intolerant or unavailable to, or have none standard treatment for various reasons; Dose expansion phase: Patients with advanced malignant solid tumor confirmed by histopathology or cytology, who have failed, been intolerant or unavailable to, or have none standard treatment for various reasons, carrying aberrant activating mutations in the KRAS pathway；
3. Presence of at least one measurable lesion (RECIST 1.1 criteria);
4. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1 point;
5. Life expectancy ≥ 12 weeks as judged by the investigator;
6. Male of childbearing potential and their heterosexual partners of childbearing potential must agree to use effective methods of contraception.

Exclusion Criteria:

A patient may not participate in this study if any of the following conditions apply:

1. Patients who priorly received SHP2 inhibitors;
2. Receiving the approved systemic antitumor treatment within 4 weeks prior to the first dose, including: chemotreatment, targeted treatment, immunization treatment, biological treatment, etc. (wash-out for 2 weeks for hormone treatment or traditional chinese medicine and chinese patent medicine with clear antitumor indications);
3. Have been in the treatment period of other interventional clinical studies (including small molecule chemicals and large molecule antibodies) within 4 weeks prior to the first dose. If participating in a non-interventional clinical study (eg, epidemiological study), you can enroll in this study; if already in the survival follow-up period of an interventional clinical study, you can enroll in this study.
4. Major surgery or radical radiotreatment (except palliative radiotreatment for metastases to bone lesions) within 4 weeks prior to first dose.
5. Central nervous system (CNS) malignant tumor or known CNS metastasis;
6. Having multiple factors that affect the absorption, distribution, metabolism or excretion of orally administered drugs (such as inability to swallow drugs, frequent vomiting, chronic diarrhoea, etc.);
7. Any other disease, metabolic abnormality, physical examination abnormal, or clinically significant laboratory test abnormality that, in the judgment of the investigator, would compromise patient compliance or give reason to suspect that the patient has a disease or condition that would compromise the interpretation of study results or place the patient at high risk.