Zenas BioPharma (ZBIO) Jefferies London Healthcare Conference 2025 summary

Pipeline and clinical progress

• Expanded pipeline through recent transactions, adding several new molecules to the portfolio.

• Obexelimab phase III trial in IgG4-related disease has completed patient enrollment, with top-line results expected by year-end.

• Lupus program with obexelimab is 70% enrolled, with a 24-week top-line endpoint readout planned for 2026.

• Phase II relapsing multiple sclerosis (RMS) data for obexelimab showed a 95% risk reduction in new lesions, setting a new benchmark for B cell targeting agents.

• Rilzabrutinib, a BTK inhibitor, is in phase III for progressive MS (PPMS), with an SPMS trial starting in Q1 2026.

Obexelimab differentiation and market opportunity

• Obexelimab offers sustained B cell inhibition via a novel mechanism, with subcutaneous administration preferred by patients.

• Market research indicates a potential 45% market share for obexelimab in IgG4-RD, with a $3B+ U.S. market opportunity.

• The phase III IgG4-RD trial is overpowered with 194 patients, using a validated design and expecting a placebo flare rate of 50-60%.

• Subcutaneous dosing allows for flexibility, such as pausing for vaccinations, and is expected to be more cost-effective for patients.

• Optimized dosing regimen validated in both IgG4-RD and RMS trials, increasing confidence in upcoming results.

BTK inhibitor (rilzabrutinib) and competitive landscape

• Rilzabrutinib is positioned as a best-in-class BTK inhibitor due to high selectivity, CNS penetration, and favorable safety profile.

• The drug is already widely prescribed in China and is considered well tolerated.

• Phase III trials for PPMS and SPMS are designed in agreement with FDA and EMA, targeting areas of high unmet need.

• The BTK inhibitor class is gaining momentum, with several competitors advancing in MS.

• Rilzabrutinib's pharmacology may offer differentiation in progressive MS compared to other BTK inhibitors.