A Phase II Study of 9MW3811 in Patients With Pathological Scar

• 9MW3811 Injection (Drug): 9MW3811 is a recombinant humanized monoclonal antibody targeting interleukin-11 (IL-11). It is administered intravenously.
• Placebo (Drug): Matching placebo solution with no active ingredient, administered intravenously.

Primary outcomes

• Change from baseline in modified Vancouver Scar Scale (mVSS) score [Up to Week 12]: There are 6 items in the mVSS scale (modified Vancouver Scar Scale), pigmentation, vascularity, pliability, thickness, pain, and itching. A total of 18 points, with minimum 0 indicating normal skin and maximum 18 indicating the most scarring and worst appearance. Change from baseline will be evaluated.
• Assessment of adverse events (AE) / serious adverse events (SAEs) [Up to Week 12]: Adverse Events occurring from ICF to last visit will be assessed and graded according to Common Terminology Criteria for Adverse Events version 6.0.
• Number of participants with abnormal vital signs [Up to Week 12]: Vital signs: include pulse, respiration, body temperature and blood pressure
• Number of participants with abnormal Physical examination findings [Up to Week 12]: Physical examination: include height, weight, head and neck, mouth, chest, abdomen, lymph nodes, nerves and mind, limbs and other sites
• Number of participants with abnormal 12-lead ECG readings [Up to Week 12]: 12-lead ECG: HR, PR, QRS, QT, QTcF,
• Number of participants with abnormal laboratory test results [Up to Week 12]: Laboratory tests: include blood routine examination, blood biochemistry, urine routine test and coagulation function

Secondary outcomes

• Change from baseline in Patient and Observer Scar Assessment Scale (POSAS) score [Up to Week 12]: POSAS includes observer scale (vascularity, pigmentation, thickness, relief, pliability, surface area) and patient scale (pain, itching, color, stiffness, thickness, irregularity). Lower scores indicate improvement.
• Change from baseline in Dermatology Life Quality Index (DLQI) score [Up to Week 12]: DLQI measures impact of skin disease on quality of life. Total score ranges 0-30; lower scores indicate better quality of life.
• Maximum Plasma Concentration (Cmax) [Up to Day 85]: To determine the pharmacokinetic (PK) of 9MW3811 following multiple intravenous infusions.
• Time to reach Cmax (Tmax) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Area under the plasma concentration versus time curve (AUC) from time 0 to the last quantifiable concentration (AUC0-t) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Terminal elimination half-life (t1/2) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• AUC from time 0 extrapolated to infinity (AUC0-inf) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Terminal elimination rate constant (λz) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Apparent clearance (CL) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Volume of distribution (Vz) [Up to Day 85]: To determine the PK of 9MW3811 following multiple intravenous infusions.
• Immunogenicity: incidence of anti-drug antibodies (ADA) [Up to Day 85]: Percentage of participants who develop detectable ADA against 9MW3811.

Other outcomes

• Change in pharmacodynamic biomarkers [Up to Day 85]: Change from baseline in blood levels of interleukin-11; Collect skin biopsy samples from the same scar lesion in patients before baseline assessment and on Day 85 to evaluate changes from baseline in: total collagen content and arrangement pattern, extracellular matrix components such as type I and type III collagen. and expression levels of fibroblast activation markers such as α-smooth muscle actin in the lesional tissue.
• Change from baseline in superficial vascularity distribution score in scar tissue [Up to Week 12]: Assessed using a 3D skin imaging device. The scar region is selected as the ROI (region of interest), and the device's built-in red area analysis function is used to quantify vascular distribution via feature count points and a derived score. One normal skin area adjacent to the scar serves as a control.
• Change from baseline in red pigment (hemoglobin) and black pigment (melanin) index in scar tissue [Up to Week 12]: Measured by a skin colorimeter under resting conditions. Depending on scar size, 1-4 measurement points are taken within the scar, and 2 points on adjacent normal skin. The mean value of each region is reported as the black pigment index (unit: arbitrary scale from the device).
• Change from baseline in skin viscoelasticity (R2 value) in scar tissue [Up to Week 12]: Assessed using a skin viscoelasticity meter. R2 = Ua/Uf, where Ua is the elastic-plastic deformation during retraction and Uf is the elastic-plastic deformation during stretching. R2 closer to 1 indicates better skin elasticity. Depending on scar size, 1-4 measurement points are taken within the scar and 1 point on adjacent normal skin. The mean R2 value of the scar region is reported (unit: ratio, dimensionless).
• Change from baseline in scar thickness measured by ultrasound [Up to Week 12]: Scar thickness is defined as the distance from the dermal-epidermal junction to the subcutaneous fat layer (strong collagen signal region). Ultrasound measurement is taken at the most prominent point of the scar (usually the center). The result is reported in millimeters (mm).
• Change from baseline in scar hardness measured by ultrasound [Up to Week 12]: Assessed using the tissue hardness measurement function of an ultrasound device. The scar region is defined as the dermis from the dermal-epidermal junction to the subcutaneous fat layer. Depending on scar size, 1-3 measurement points are taken within the scar, and the mean value is reported. Units are as provided by the device (e.g., kilopascals \[kPa\] or relative stiffness units).

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Age ≥18 years
* Pathological scar with no spontaneous regression over the prior 6 months
* At least one scar with modified Vancouver Scar Scale (mVSS) score ≥9
* Willing to use effective contraception for 6 months after last dose (if of childbearing potential)
* Provide written informed consent

Exclusion Criteria:

* Contracture scar causing deformity
* All eligible scars either >10 cm in length and >5 cm in width, or located exclusively on sun-exposed areas (head, face, hands)
* Evidence of scar infection or active systemic infection requiring treatment
* Use of anti-scar medications (e.g., corticosteroids, immunosuppressants) or anti-scar procedures (surgery, laser, radiation, etc.) within 4 weeks prior to first dose
* Prior treatment with IL-11 cytokine or IL-6 family targeted therapy (e.g., tocilizumab) within specified washout periods
* Participation in another interventional study within 28 days
* Positive serology for HBV, HCV, HIV, or syphilis with clinical significance
* History of severe allergy or known hypersensitivity to study drug components
* Clinically significant laboratory abnormalities (eGFR <90 mL/min/1.73m², PLT <100×10⁹/L, QTc >450/470 ms, bilirubin >1.5×ULN, AST/ALT >1.5×ULN)
* Alcohol or drug abuse within 1 year
* Pregnancy, breastfeeding, or unwillingness to use contraception
* Any other condition that, in the investigator's judgment, would compromise subject safety or study compliance