Disease control observed in all three patients at the first and lowest dose level, supporting continued dose escalation
Hangzhou, China, September 15, 2026 — Biotle, a clinical-stage biotechnology company developing next-generation antibody therapeutics, today announced encouraging preliminary clinical data from the first dose cohort of its ongoing Phase 1/2 study of BTL-101, a fully human BCMA×GPRC5D×CD3 trispecific T-cell engager (TCE) for relapsed or refractory multiple myeloma (RRMM).
Three patients were treated in the first and lowest dose cohort with a 0.125 mg priming dose followed by 0.5 mg every two weeks (subcutaneous dosing). At the current efficacy assessments, all three patients achieved disease control, with stable disease as the best response to date and no progressive disease observed at the initial assessments.
Favorable changes were observed across multiple myeloma disease markers, providing evidence of early antimyeloma activity at the lowest dose tested. Patients remain on treatment and responses continue to mature with additional follow-up.
“We are very encouraged to observe disease control across all three patients at our starting dose level,” said Dr Jiansong Yang, CEO of Biotle. “This first cohort was designed primarily to establish safety and characterize human pharmacology rather than to maximize efficacy. The early antimyeloma activity observed provides important clinical validation of BTL-101 and supports continued dose escalation.”
Encouraging early safety and pharmacodynamic profile
BTL-101 demonstrated clear evidence of T-cell pharmacodynamic activity in the first cohort.
To date:
- No dose-limiting toxicities have been observed
- No ICANS has been observed
- Cytokine release syndrome observed to date has been low grade and transient
- Cytokine activation was predominantly associated with the first effective exposure and was substantially attenuated with subsequent dosing
Importantly, antimyeloma activity was also observed in a patient without clinically apparent CRS, demonstrating that antimyeloma activity can be observed in the absence of clinically apparent CRS.
Dose escalation to evaluate deeper responses
Based on the safety, pharmacodynamic and preliminary efficacy findings from the first cohort, the next dose level is planned. The Company will assess whether increased exposure can translate the disease control observed at the starting dose into deeper objective responses, while maintaining a manageable safety profile. Patients in the first cohort will also continue treatment and follow-up to evaluate whether responses deepen over time.
Designed to address tumor heterogeneity and antigen escape
BTL-101 simultaneously targets BCMA and GPRC5D, two validated multiple myeloma antigens, while engaging CD3-positive T cells.
The dual-antigen design is intended to broaden tumor-cell recognition and reduce dependence on a single antigen, potentially addressing tumor heterogeneity and antigen escape, including in patients whose disease has progressed following prior BCMA-directed therapies.
“As BCMA-directed CAR-T therapies and T-cell engagers move earlier in the multiple myeloma treatment landscape, there is a growing need for therapies that can address disease emerging after single-antigen-directed treatment,” said Dr Yang. “We believe BTL-101’s dual-antigen approach has the potential to address this important unmet need.”
About BTL-101
BTL-101 is Biotle’s proprietary, fully human BCMA×GPRC5D×CD3 trispecific T-cell engager for the treatment of multiple myeloma. BTL-101 combines dual tumor-antigen recognition with an affinity-optimized, fully human CD3-binding arm in an IgG-like antibody format. BTL-101 has also demonstrated excellent CMC properties, including robust manufacturability and favorable physicochemical stability, supporting scalable production and future commercial development. Preclinical studies demonstrated potent antimyeloma activity, including activity in models with heterogeneous expression of BCMA and GPRC5D. BTL-101 is currently being evaluated in a first-in-human Phase 1/2 clinical study in patients with RRMM.
About Biotle
Biotle is a clinical-stage biotechnology company focused on developing next-generation multispecific antibody therapeutics for cancer and autoimmune diseases.
For more information, visit www.biotle.com.
