IGM Biosciences
IGM Biosciences engineered antibodies of the IgM class, which have ten binding arms instead of two, originally as T-cell engagers for blood cancers and later for autoimmune disease. It ended development and was bought by Concentra Biosciences in 2025.
Overview
IGM Biosciences was a biotechnology company that focused on developing engineered IgM-based therapeutic antibodies, exploiting the ten binding sites of the IgM format for T-cell engagers and other constructs. By mid-2025 the company had wound down development; on 1 July 2025 it agreed to be acquired by Concentra Biosciences for $1.247 per share in cash plus a contingent value right entitling holders to closing net cash above $82 million and 80% of net proceeds from any disposition of product candidates within a year. The tender offer and merger completed on 14 August 2025 and the Nasdaq listing (IGMS) ended. The company's website (igmbio.com) no longer resolves. Its earlier oncology programmes (including CD20xCD3 IgM T-cell engagers) are not described in the fetched filings.
Funding
All startupsInvestors not recorded; see the round sources.
| Round | Year | Amount | Source |
|---|---|---|---|
| Acquisition · $1.247 in cash per share plus a contingent value right; agreement 1 July 2025, merger completed 14 August 2025 | 2025 | undisclosed | sec.gov |
Amounts only where the cited source states them. Rounds without a public source are not listed.
Notes
top- Former Nasdaq ticker IGMS. The company had pivoted from oncology to autoimmune disease before winding down; that pivot is not documented in the fetched sources. The July 2025 release is datelined Mountainview while the August 8-K lists a San Mateo address.
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