LongBio Pharma (Suzhou) Co., Ltd. (HKG: 1779) announced that top‑line data from its China Phase II clinical trial of LP‑005 have been reported, demonstrating significant efficacy together with a favorable safety and tolerability profile in patients with paroxysmal nocturnal hemoglobinuria (PNH). LP‑005 is a self‑developed bifunctional antibody‑fusion protein targeting the complement proteins C5 and C3b, designed to deliver potent control of hemolysis and robust improvement in hemoglobin levels.
Clinical Trial Snapshot
| Item | Detail |
|---|---|
| Company | LongBio Pharma (Suzhou) Co., Ltd. (HKG: 1779) |
| Candidate | LP‑005 – bifunctional antibody‑fusion protein targeting complement C5 and C3b |
| Indication | Paroxysmal nocturnal hemoglobinuria (PNH) |
| Trial Phase / Region | Phase II, China |
| Enrollment | 30 PNH patients; 27 completed the 24‑week treatment |
| Dose Groups | Three dose groups, including 1,200 mg and 1,500 mg (third dose level not disclosed) |
| Primary Endpoints | (1) Change from baseline in serum LDH at Week 12; (2) proportion achieving transfusion independence with Hb increase ≥2 g/dL from baseline at Week 24 |
| Data Status | Top‑line data reported 21 Oct 2026 |
Drug Profile & Mechanism of Action
- Molecule: LP‑005, a self‑developed bifunctional antibody‑fusion protein.
- Targets: Dual complement blockade of C5 and C3b – the terminal and proximal arms of the complement cascade, respectively.
- Mechanistic Rationale: In PNH, uncontrolled complement activation destroys red blood cells. C5 inhibition blocks terminal‑pathway‑driven intravascular hemolysis, while C3b targeting addresses proximal complement activation associated with extravascular hemolysis – a known limitation of C5‑inhibitor monotherapy, positioning LP‑005 to control both hemolysis pathways simultaneously.
- Observed Pharmacology: Potent hemolysis control (LDH suppression) with robust hemoglobin improvement and complete transfusion avoidance across dose groups in the Phase II trial.
Clinical Evidence – Phase II Top-Line Results
| Endpoint | Result | Assessment |
|---|---|---|
| Serum LDH Change at Week 12 (primary) | Significant decrease from baseline (exact magnitude not disclosed) | Primary endpoint met |
| Hemolysis Control Rate at Week 12 (LDH < 1.5 × ULN) | 100% in both the 1,200 mg and 1,500 mg dose groups | Complete hemolysis control |
| Transfusion Avoidance Rate | 100% in all three dose groups; 100% (7/7) in the 1,500 mg group at Week 24 | No transfusions required |
| Breakthrough Hemolysis (BTH) | None observed in any dose group through Week 24 | Durable control |
| Hb Increase ≥2 g/dL Without Transfusion at Week 24 (primary) | 85.7% (6/7) in the 1,500 mg dose group | Primary endpoint met |
| Hb ≥120 g/L at Week 24 | 71.4% (5/7) in the 1,500 mg dose group | Near‑normal hemoglobin levels |
| Safety & Tolerability | Favorable profile (detailed adverse‑event data not disclosed) | Supports continued development |
The trial enrolled 30 PNH patients, of whom 27 completed the 24‑week treatment. At Week 12, LDH levels showed a significant decrease from baseline, with the hemolysis control rate (LDH below 1.5 × ULN) reaching 100% in both the 1,200 mg and 1,500 mg dose groups, and a 100% transfusion avoidance rate with no breakthrough hemolysis across all three dose groups. At Week 24, the 1,500 mg group achieved 85.7% (6/7) Hb increase ≥2 g/dL without transfusion and 71.4% (5/7) Hb ≥120 g/L, with 100% (7/7) transfusion avoidance and no BTH observed – evidence that LP‑005 delivers potent control of hemolysis and robust improvement in hemoglobin levels.
Market Impact & Outlook
- Dual‑Target Differentiation: By hitting both C5 and C3b, LP‑005 is designed to overcome the extravascular hemolysis liability of established C5 inhibitors, potentially raising the treatment bar in the complement‑inhibitor class for PNH.
- Best‑in‑Class Signals: 100% hemolysis control, 100% transfusion avoidance, and zero BTH in the Phase II population are hallmarks of deep complement suppression and durable disease control.
- China Biotech Advancement: The readout reinforces LongBio Pharma’s position in China’s expanding complement‑targeted therapeutics landscape, with PNH among the most clinically validated indications for the modality.
- Next Steps: Detailed Phase II data presentation, dose selection, and Phase III planning were not disclosed; subsequent regulatory strategy and partnership plans remain not yet announced.
Forward‑Looking Statements
This brief contains forward‑looking statements regarding LP‑005’s clinical development, including potential efficacy, safety, and advancement in PNH based on Phase II top‑line data. Top‑line results are preliminary and subject to further analysis and verification. Actual outcomes may differ materially due to risks including full data review results, subsequent trial design and enrollment, regulatory requirements, and competitive dynamics in complement‑targeted therapies.-Fineline Info & Tech
