Codexis, Inc. (NASDAQ: CDXS) announced an agreement with an undisclosed siRNA drug developer to explore stereo-defined oligonucleotide fragment synthesis using its ECO Synthesis Manufacturing Platform, according to a company press release dated Sept. 28, 2026.

Under the agreement, Codexis will produce stereo-defined oligonucleotide fragments through a fully enzymatic process. Those fragments will then be supplied to the partner company to assemble into a final duplex via ligation. The collaboration will also compare the enzymatically synthesized fragments against conventional solid-phase oligonucleotide synthesis (SPOS), evaluating purity, product quality, and ligation performance.

The agreement follows a presentation at TIDES USA 2026, where Codexis said it demonstrated full-length siRNA synthesis with precise control of phosphorothioate stereochemistry using StereoSelect, a capability within the ECO Synthesis platform.

Alison Moore, PhD, President and CEO of Codexis, said the collaboration offers "an exciting opportunity to demonstrate how ECO Synthesis can deliver stereochemical control, which may offer both superior product quality and therapeutic performance to an innovator's pipeline over assets produced using traditional solid phase chemistry methods."

The results of the comparison are intended to help the unnamed partner evaluate the technology's potential for future clinical development programs. The identity of the siRNA innovator was not disclosed in the announcement.