A Phase III Clinical Study to Evaluate the Efficacy, Safety, and Tolerability of Plonmarlimab in Subjects With Relapsed/Refractory Rheumatic and Immunologic Disease-associated Haemophagocytic Lymphohistiocytosis (Also Known as Macrophage Activation Syndrome [MAS])

NCT07208058 | Recruiting Phase 3

• 1 other identifier: THZ0103-MAS301
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 15

Brief Summary

A study designed to evaluate the efficacy, safety, immunogenicity, PK, and PD characteristics of Plonmarlimab in patients with relapsed/refractory rheumatic and immunologic disease-associated MAS, and to explore biomarkers related to the efficacy of Plonmarlimab.

Conditions

Relapsed/Refractory Rheumatic and Immunologic Disease-associated Haemophagocytic Lymphohistiocytosis

Outcome Measures

Primary Outcomes (1)

• Overall response rate (ORR)

  at the end of Week 8

Study Arms (1)

Plonmarlimab

EXPERIMENTAL

Drug: Plonmarlimab

Interventions

Plonmarlimab DRUG

Subjects will receive Plonmarlimab 10 mg/kg by intravenous injection once weekly from Week 1 to Week 3, and Plonmarlimab 6 mg/kg by intravenous injection once weekly from Week 4 to Week 8 (10 mg/kg QW×3 + 6 mg/kg QW×5).

Plonmarlimab

Eligibility Criteria

• Age: 16 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Age: 16 to 80 years (inclusive), of any gender.
• The subject is willing to participate in this study and voluntarily signs the informed consent form. For minor subjects aged 16 years (inclusive) to less than 18 years, written informed consent must be signed by both the subject and the subject's legal guardian.
• Diagnosed with a rheumatic and immunological disease.
• Diagnosed with haemophagocytic lymphohistiocytosis (HLH) according to the HLH-2004 diagnostic criteria (excluding molecular diagnosis)
• No response to/or dependence on/intolerance to/or worsening during high-dose corticosteroid therapy. High-dose corticosteroid therapy: at least 1.5-2.0 mg/kg/d of prednisone or its equivalent dose for 3 consecutive days, including methylprednisolone pulse therapy (15-30 mg/kg/d, maximum dose 1 g/d, for 3-5 days).

You may not qualify if:

• Confirmed or suspected primary haemophagocytic lymphohistiocytosis (pHLH).
• HLH induced by infection (including but not limited to EBV-HLH) or treatment (including but not limited to drugs such as CAR-T cells, TCEs, ADCs).
• History of other active neoplasm malignant within 5 years prior to screening, with the exception of successfully treated cutaneous basal cell or squamous cell carcinoma, or localised neoplasms that have been adequately treated with curative intent, including but not limited to, uterine carcinoma in situ, breast cancer in situ, thyroid cancer, etc.; asymptomatic, localised prostate cancer confirmed to have no metastasis and not requiring treatment, etc. Prior to receiving the investigational drug, an assessment by an oncology specialist is required to clarify the current status of the neoplasm malignant and to rule out the possibility of HLH secondary to the neoplasm malignant.
• History of allergy to any component of the investigational drug.
• Lung disorder: including but not limited to asthma, chronic obstructive pulmonary disease, interstitial lung disease, alveolar proteinosis, pulmonary granulomatosis, etc., and abnormal pulmonary function tests: forced vital capacity (FVC) \<80% of predicted value, or FEV1/FVC \<70%, etc.; or the investigator's comprehensive assessment concludes that the subject has a pre-existing lung disease that significantly affects pulmonary function and is unsuitable for participation in this clinical study.
• Cardiovascular disorder: history of acute myocardial infarction or unstable angina pectoris, severe arrhythmia (multifocal frequent premature ventricular contractions, ventricular tachycardia, ventricular fibrillation), etc., within the last 6 months; New York Heart Association (NYHA) functional class III-IV.
• Infection: Presence of an infection deemed uncontrollable by the investigator during the screening period \[including but not limited to tuberculosis, active syphilis infection, viral infection (EBV, CMV, COVID-19, active hepatitis B, active hepatitis C, human immunodeficiency virus), other bacterial infections (including but not limited to atypical mycobacteria, Shigella, Salmonella, Campylobacter, etc.)\].
• Abnormal renal function: creatinine (Cr) or urea/blood urea nitrogen (BUN) test value \>1.5 times the upper limit of normal (ULN); or eGFR \<60 mL/min during the screening period, calculated using the MDRD formula: eGFR \[mL/(min × 1.73 m2)\] = 186 × serum creatinine (mg/dL)-1.154 × age (years)-0.203 × (0.742 if female) × 1.233.
• Haematological diseases: Subjects with a past or current history of haematological diseases (including but not limited to, myelofibrosis, aplastic anaemia, leukaemia, lymphoma, etc.).
• Surgery or other conditions: Planned surgery or any other medical history, laboratory test abnormal, or other condition that, in the investigator's judgment, makes the subject unsuitable for participation in this study.
• Transplant: History of major organ transplant (e.g., heart, lung, kidney, liver) or haematopoietic stem cell/bone marrow transplant.
• Other diseases: Subject currently has a clinically significant and clinically unstable or inadequately controlled acute or chronic disease (e.g., acute pneumonia, pulmonary arterial hypertension, diabetic ketoacidosis, pancreatitis acute, etc.).
• Pregnant or lactating women.
• Participation in any clinical trial (including investigational vaccines) treatment or use of an invasive investigational medical device within 3 months prior to enrolment, or currently enrolled in an interventional study.
• Received live vaccine within 30 days prior to screening.

Sponsors & Collaborators

• TJ Biopharma Co., Ltd.: lead

Study Sites (15)

Beijing Friendship Hospital, Capital Medical University

Beijing, Beijing Municipality, China

RECRUITING

Peking Union Medical College Hospital, Chinese Academy of Medical Sciences

Beijing, Beijing Municipality, China

NOT YET RECRUITING

Peking University People's Hospital

Beijing, Beijing Municipality, China

NOT YET RECRUITING

Sun Yat-sen Memorial Hospital, Sun Yat-sen University

Guangzhou, Guangdong, China

NOT YET RECRUITING

The Second Hospital of Hebei Medical University

Shijiazhuang, Hebei, China

NOT YET RECRUITING

Children's Hospital of Zhengzhou University

Zhengzhou, Henan, China

NOT YET RECRUITING

The First Affiliated Hospital of Zhengzhou University

Zhengzhou, Henan, China

NOT YET RECRUITING

Union Hospital, Tongji Medical College, Huazhong University of Science and Technology

Wuhan, Hubei, China

NOT YET RECRUITING

The First Affiliated Hospital of Nanchang University

Nanchang, Jiangxi, China

NOT YET RECRUITING

The First Affiliated Hospital of China Medical University

Shenyang, Liaoning, China

NOT YET RECRUITING

Children's Hospital of Fudan University

Shanghai, Shanghai Municipality, China

NOT YET RECRUITING

Huashan Hospital, Fudan University

Shanghai, Shanghai Municipality, China

NOT YET RECRUITING

Renji Hospital, Shanghai Jiao Tong University School of Medicine

Shanghai, Shanghai Municipality, China

RECRUITING

Tianjin Medical University General Hospital

Tianjin, Tianjin Municipality, China

NOT YET RECRUITING

The First Affiliated Hospital, Zhejiang University School of Medicine

Hangzhou, Zhejiang, China

NOT YET RECRUITING

MeSH Terms

Conditions

Recurrence

Interventions

plonmarlimab

Condition Hierarchy (Ancestors)

Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Biwei Zeng

CONTACT

86 13540060494; biwei.zeng@tjbio.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 27, 2025
• First Posted: October 6, 2025
• Study Start: November 21, 2025
• Primary Completion (Estimated): December 20, 2026
• Study Completion (Estimated): November 30, 2027
• Last Updated: December 2, 2025

Record last verified: 2025-11

Locations

CN (15)