Zymeworks licenses ZW209 trispecific T cell engager to Roche

Zymeworks has signed an exclusive global licence and collaboration agreement with Roche for ZW209, a trispecific T cell engager targeting DLL3, a surface protein predominantly expressed in small cell lung cancer and related neuroendocrine tumours. The deal delivers $55 million upfront and a further $40 million on initiation of the Phase 1b trial, with up to $718 million in development, commercial and sales-based milestones, plus tiered royalties in the high-single-digit to mid-teen percentage range on future net sales. Patent protection extends into the 2040s.

Under the terms, Zymeworks will run the Phase 1a monotherapy study in collaboration with Roche, which will fund that trial and take responsibility for all subsequent global development and commercialisation. The US FDA has already cleared an IND for ZW209, and Zymeworks said additional regulatory filings are planned to open clinical sites outside the United States. The transaction remains subject to the expiry of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and other customary closing conditions.

The science behind ZW209

ZW209 is configured as a trispecific antibody that binds DLL3 on tumour cells while simultaneously engaging CD3 and CD28 on T cells. The CD28 co-stimulatory arm is central to the design rationale: conventional CD3-only bispecific T cell engagers can drive T cell exhaustion over time, and CD28 co-stimulation is intended to sustain T cell proliferation and survival for more durable tumour killing. Zymeworks says preclinical studies showed enhanced long-term cytotoxicity in vitro compared with a CD3-only benchmark. The candidate is built on the company's TriTCE Co-Stim framework, together with its Azymetric and EFECT antibody engineering platforms.

Adam Schayowitz, Executive Vice President and Head of R&D at Zymeworks, said the agreement "reflects our broader strategy of generating innovative programs through our R&D engine and partnering selected assets in ways that share development risk while preserving meaningful participation in their future success." Boris Zaïtra, Head of Corporate Business Development at Roche, described ZW209 as "an innovative approach that complements our ongoing efforts to develop new treatment options for people living with lung cancer."

Market context and competitive landscape

DLL3 has attracted sustained industry interest as a target in small cell lung cancer, an aggressive disease with historically limited treatment options. The antigen's high and relatively selective expression on SCLC and neuroendocrine tumour cells makes it an attractive address for T cell-redirecting therapies. Several large pharma and biotech groups have programmes in this space, spanning bispecific and antibody-drug conjugate formats, and early clinical data from other DLL3-directed agents have shown meaningful response rates in heavily pre-treated populations.

Roche's decision to in-licence a trispecific rather than advance its own bispecific underscores the industry's evolving view that CD28 co-stimulation may be necessary to achieve durable responses in solid tumour settings, where the immunosuppressive microenvironment remains a central challenge. Zymeworks itself has additional multispecific T cell engager programmes in solid tumours, haematological cancers and autoimmune and inflammatory diseases, suggesting ZW209 is unlikely to be its last out-licensing event.

For Zymeworks, the deal strengthens a balance sheet that also draws on royalties from its HER2-targeted bispecific zanidatamab, commercialised through Jazz Pharmaceuticals and BeOne Medicines, and from revefenacin, marketed as YUPELRI. The near-term $95 million in expected cash provides meaningful runway as the company pursues its asset aggregation strategy alongside active internal research and development.