Mosaic Biosciences launches Tessaic Nano for rapid nanobody discovery

Mosaic Biosciences has launched Tessaic Nano, a fully human synthetic in vitro VHH library aimed at speeding nanobody discovery for therapeutic, diagnostic and research programs. The release gives clients a second single-domain discovery path alongside Mosaic’s in vivo partnership with Abkyu.

Why it matters: - Tessaic Nano gives biopharma teams a fully human in vitro option for nanobody discovery. - The library can shorten timelines by removing the camelid immunization step and the humanization step often needed for camelid-derived VHHs. - Mosaic is positioning the launch as part of a broader single-domain discovery menu that includes its in vivo work with Abkyu.

What happened: - Mosaic Biosciences announced the launch of Tessaic Nano, a fully human synthetic VHH library for rapid nanobody discovery. - The library is designed for therapeutic, diagnostic and research applications. - Tessaic Nano is the first library in Mosaic’s Tessaic antibody library system. - Mosaic said Tessaic Fab, a set of curated Fab-format libraries, is also near launch. - Tracey Mullen, chief strategy officer at Mosaic Biosciences, said clients are increasingly running in vitro and in vivo VHH discovery in parallel to reduce timeline risk and compare candidate profiles. - Mosaic said Tessaic Nano is available now.

The details: - Tessaic Nano is a fully in-house route to single-domain candidates. - The library requires no humanization. - The library requires no camelid immunization step. - The design includes donor-derived CDRH3 diversity. - The design also incorporates curated diversity across CDRH1 and CDRH2. - Mosaic said internal repertoire analysis informed which diversity placements produced the strongest hit rates. - Diversity is sourced from immune material captured and processed entirely in-house. - Germlines are selected using literature-backed developability and pairing data. - Liability filtering is built into the design from the start rather than handled later. - Mosaic said the fully human format can shorten development timelines for programs headed toward the clinic.

Between the lines: - The launch expands Mosaic’s ability to offer both in vitro and in vivo single-domain discovery under one program. - The preferred partnership with Abkyu gives Mosaic clients access to a parallel in vivo route. - The company is signaling that clients may want multiple discovery tracks running at once to lower program risk. - The emphasis on human sourcing and built-in developability suggests a push to make early candidates easier to advance.

What's next: - Mosaic plans to introduce Tessaic Nano at Festival of Biologics Basel on October 13–15. - Mosaic also plans to feature the library at PEGS Europe on November 16–19. - Tessaic Fab is expected to follow as the next library in the Tessaic system.

The bottom line: - Mosaic is betting that a fully human synthetic VHH library, paired with an in vivo partner, will make nanobody discovery faster and more flexible for drug developers.