A Phase I Clinical Study of SSS59 Monotherapy in Patients With Advanced Malignant Tumors

This study includes 4 Parts: Part A1 (dose escalation and dose extension for QW administration), Part A2 (dose escalation and dose extension for Q2W administration), Part A3 (dose extension for Q3W administration), and Part B (indication extension, such as advanced gastric or gastroesophageal junction adenocarcinoma with MUC17 positive, failure of standard therapy, or intolerance to standard therapy , or other tumors).

• SSS59 (Drug): A humanized antibody targeting MUC17

Primary outcomes

• DLTs [21 days]: Dose limiting toxicity
• Safety and tolerability [during the intervention，Within 28 days of the last dose]: Safety and tolerability assessed by incidence and severity of adverse events
• MTD and RP2D [through study completion, an average of 2 year]: Determine the maximum tolerated dose and determine the recommended phase II dose

Secondary outcomes

• Cmax of SSS59 [baseline, during the intervention and at the end of the study]: Maximum concentration
• Tmax of SSS59 [baseline, during the intervention and at the end of the study]: Time to peak drug concentration
• AUC0-last of SSS59 [baseline, during the intervention and at the end of the study]: the area under the curve (AUC) up to the last measurable concentration
• RO of SSS59 [baseline, during the intervention and at the end of the study]: Receptor Occupancy
• Pharmacodynamic (PD) characteristics of SSS59 [baseline, during the intervention and at the end of the study]: change of cytokine
• Immunogenicity of SSS59 [baseline, during the intervention and at the end of the study]: ADA，NAB（if ADA is positive）
• Preliminary antitumor activity of SSS59 [baseline, during the intervention and at the end of the study]: Assessed according to Recist V1.1

Sex: All, ages: 18 Years to 75 Years

Inclusion Criteria:

* Histologically and/or cytologically documented local advanced or recurrent or metastatic malignancies.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.
* Expected survival >3 months.
* Signed informed consent form.
* Must have adequate organ function.

Exclusion Criteria:

* Any remaining AEs > grade 1 from prior anti-tumor treatment as per CTCAE v5. 0, with exception of hair loss and fatigue.
* Pregnant or nursing women or women/men who are ready to give birth.
* symptomatic central nervous system metastasis.
* Allergy to other antibody drugs or any excipients in the study drugs.
* Underwent major surgery within 4 weeks prior to first dosing.
* The patient is participating in another clinical study, unless it is an observational (non-intervention) clinical study or a follow-up period of an intervention study.

The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.