News

HANGZHOU, China — September 8, 2025 — Biotle today announced positive preclinical pharmacokinetic/pharmacodynamic (PK/PD) results for BTL-203, the company’s half-life–extended neonatal Fc receptor (FcRn) inhibitor. In cynomolgus monkeys, BTL-203 produced deep and sustained reductions in total IgG after single-dose intravenous (IV) or subcutaneous (SC) administration. Using a semi-mechanistic FcRn–IgG turnover model calibrated to these data, simulations project that subcutaneous dosing every four weeks (Q4W) could maintain clinically meaningful IgG suppression in humans.

“These encouraging data, together with our translational modeling, suggest BTL-203 could offer once‑every‑four‑weeks subcutaneous dosing—meaningfully less frequent than today’s approved FcRn regimens, which are administered in weekly cycles. We believe this convenience, alongside potent IgG lowering, positions BTL-203 as a potential best‑in‑class therapy, subject to confirmation in clinical studies.”

— Dr. Jiansong Yang, CEO of Biotle

Nonclinical Highlights

• Robust IgG lowering vs comparator: Single IV doses of BTL-203 (60 or 30 mg/kg) achieved higher systemic exposure and deeper, more sustained total‑IgG reductions than efgartigimod IV (48.5 mg/kg) in the study; nadir decreases were ~67–69% with recovery by ~4 weeks.
• SC administration: BTL-203 15 mg/kg SC produced total‑IgG reduction comparable to efgartigimod 48.5 mg/kg IV.
• Translational projection: Population PK/PD modeling suggests Q4W SC dosing in humans could sustain IgG lowering within a target therapeutic window; this will be tested prospectively in clinical trials.
• Safety & tolerability: BTL-203 was well-tolerated in cynomolgus monkeys. At 15 mg/kg SC, albumin decreases and LDL‑C changes were minimal and reversible.

Potential differentiation. Approved FcRn therapies today are delivered in weekly (SC) or biweekly (IV) treatment cycles. If confirmed clinically, a Q4W SC maintenance regimen would represent a less frequent dosing schedule for an FcRn inhibitor.

About BTL-203

BTL-203 is an FcRn inhibitor engineered for extended exposure and infrequent subcutaneous dosing. By blocking FcRn, BTL-203 accelerates IgG catabolism—a validated mechanism across multiple IgG‑mediated diseases. Biotle is advancing BTL-203 toward clinical development (planned IND submission in Q2 2026) and is engaging potential partners to accelerate global development and commercialization.

Business Development: contact us to explore partnering opportunities.

Biotle today announced that its Chief Executive Officer, Dr. Jiansong Yang, will attend Bio Europe 2025, taking place November 3–5 in Vienna, Austria, to pursue partnering opportunities for BTL-101 and BTL-203. Dr. Yang will provide updated status and target disclosure at the conference.

BTL-101 (targets undisclosed). BTL-101 is a pioneering trispecific T-cell engager built on Biotle’s TriME® platform, designed to address tumor heterogeneity in relapsed or refractory multiple myeloma and select autoimmune indications. Highlights include:

• Simultaneous targeting of CD3ε and two tumor-associated antigens (TAAs) to overcome antigen escape and resistance.
• Fully human, high-affinity binding domains with low CD3ε affinity to reduce cytokine-release risk.
• Fc LALAPG silencing to prevent unwanted T-cell clearance.
• High subcutaneous bioavailability (~100% in mice) and stable high-concentration formulation (>100 mg/mL).
• Projected once-every-4-weeks subcutaneous dosing; strong CMC profile (7–8 g/L titers; 4-week stability at 40 °C).
• Demonstrated potent, precise tumor-cell killing with minimal off-target effects in preclinical models.

BTL-203 (an FcRn inhibitor with extended half-life). A next-generation bispecific antibody designed for deep, durable effect with convenient once-every-4-weeks subcutaneous dosing for autoimmune diseases. Advantages include:

• Extended exposure and stabilized effect.
• Deep & durable effect linked to superior outcomes in autoimmune diseases.
• Improved convenience and compliance vs. weekly or biweekly dosing by competitors.
• Supports broad indication expansion in chronic autoimmune diseases.

Tigermed’s new headquarter and life‑science campus in Binjiang, Hangzhou has completed construction and passed final acceptance. Biotle will be the first biotech to move into Tigermed’s on‑site incubator. Our new office is planned to be ready for move‑in during Q1 2026, supporting our continued growth in innovative therapeutics.

We look forward to welcoming partners and stakeholders to our new headquarter as we pursue our mission of transforming cancer care worldwide.