About Trellis Bioscience
Trellis Bioscience develops human antibodies that break down bacterial biofilms, so antibiotics can treat persistent infections. Its lead drug, calpurbatug (TRL1068), is an investigational antibody for chronic prosthetic joint infections. The company is pairing it with antibiotics and surgical debridement. The aim is to control the infection while keeping the patient's implant. The antibodies come from CellSpot, a platform that finds rare, naturally occurring human antibodies.
Trellis is a clinical-stage company in Redwood City, California. On July 16, 2026, it announced a closed $9 million Series C to complete a Phase 2 trial of calpurbatug. The FDA has given TRL1068 Orphan Drug, Fast Track and Qualified Infectious Disease Product designations. Larry Kauvar is the founder and chief science officer. Nora Mende is chief financial officer. The pipeline also includes antiviral antibodies, and one of them is in a clinical trial.
Funding Rounds (SEC Form D)
| First sale | Filed with SEC | Amount sold | Investors | Avg. check | Terms | Filing |
|---|---|---|---|---|---|---|
| Oct 4, 2024 | Oct 21, 2026 | $4,094,500target not set | 27 | $151K | Equity, Options, Series 2024 Bridge. Includes convertible notes with 20% warrant coverage.Rule 506(b) | Form D ↗ |
| Apr 20, 2023 | Oct 21, 2026 | $1,350,000target not set | 9 | $150K | Equity, Options, Series 2023 Bridge. Includes convertible notes with 20% warrant coverage.Rule 506(b) | Form D ↗ |
| Jun 1, 2022 | Oct 21, 2026 | $985,000target not set | 6 | $164K | Equity, Options, Series 2022 Bridge. Includes convertible notes with 20% warrant coverage.Rule 506(b) | Form D ↗ |
| Apr 29, 2010 | Oct 21, 2026 | $22,892,056target not set | 88 | $260K | Equity, Options, Series B InterestsRule 506(b) | Form D ↗ |
| Jan 30, 2026 | May 15, 2026amended Oct 29, 2026 | $9,093,000target not set | 16 | $568K | Equity, Series C InterestsRule 506(b) | Form D/A ↗1 earlier filing |
| Oct 27, 2011 | Nov 9, 2011 | $235,000of $300K target | 8 | $29,375 | Debt, Securities on exercise, Issuance of Convertible Promissory Notes and Warrants, the underlying shares of preferred stock issuable upon the conversion of the convertible promissory notes and the common stock issuable upon conversion of such preferred stock and upon the exercise of06 | Form D ↗ |
| Jul 8, 2009 | Jul 17, 2009amended Aug 7, 2009 | $11,715,708of $13.5M target | 12 | $976K | Equity06 | Form D/A ↗1 earlier filing |
| Total, seven offerings | $50,365,264 | |||||
First sale is the date the first investor in the offering committed to invest. Companies must file Form D within 15 days of that date, so filing dates run later.
Rounds announced by Trellis Bioscience
What the company said publicly about its funding. Announced amounts can differ from Form D figures: an announcement can combine several closings, and some money is raised without a Form D.
| Announced | Round | Amount | Investors | Source |
|---|---|---|---|---|
| Jul 16, 2026 | Series C | $9 million | New Science Ventures, Easton Capital, AMR Action Fund, The Doctor Group of Dallas, Texas, and orthopedic surgeons | PR Newswire: Trellis Bioscience raises $9 million to advance clinical development of calpurbatug (TRL1068) ↗ |
| Feb 13, 2007 | Series B | $10 million | Fierce Biotech: Trellis Bioscience Raises $10 Million In Series B Venture Round ↗ |
Why Investors Backed Trellis Bioscience
Trellis Bioscience develops human antibodies that target bacterial biofilms. Its lead drug, calpurbatug (TRL1068), is aimed at chronic prosthetic joint infections. On July 16, 2026, the company announced a closed $9 million Series C to complete a Phase 2 trial of the drug. The round included existing investors and new ones, among them AMR Action Fund.
The problem it targets
Biofilms form a protective matrix around bacteria. That matrix makes infections harder for antibiotics and the immune system to clear. For chronic prosthetic joint infections, the current standard of care is two-stage exchange arthroplasty, a surgical procedure. In May 2023, chief executive officer Stefan Ryser said Trellis would test in Phase 2 whether TRL1068 can spare patients from surgery.
What the product does
Calpurbatug is a native human monoclonal antibody. It binds DNABII proteins, which help hold together the DNA scaffold of a biofilm. Removing those supports weakens the matrix and releases bacteria, so antibiotics can act on susceptible cells. Trellis finds its antibodies by cloning them from human white blood cells. For infectious diseases, it draws on patients who have recovered from the disease. In 2023, Larry Kauvar, the chief science officer, said he expects the antibody can be given repeatedly without triggering neutralizing antibodies.
Progress so far
In May 2023, Trellis reported interim Phase 1 results in patients with prosthetic joint infections. Six of 8 patients (75%) given one dose plus standard antibiotics had a biofilm burden below 100 CFU/mL of sonication fluid after 7 days. The company compared that with 15% in historical data. In two patients, biofilm fell below the limit of detection. The drug was well tolerated across the two dose groups analyzed, with no drug-related adverse events. The analysis covered the first 11 patients, and the study aims to randomize 18. Trellis has also developed TRL345, a native human antibody against human cytomegalovirus, under an SBIR grant.
Who backs it
The Series C drew continued support from existing investors New Science Ventures and Easton Capital. New investors include AMR Action Fund, The Doctor Group of Dallas, Texas, and orthopedic surgeons with expertise in prosthetic joint infections. Total equity funding is now about $35 million. Grant support of a similar size has come from NIAID and CARB-X, a global nonprofit partnership. Junjun Gao, PhD, a principal, was appointed to the Trellis board of directors in conjunction with AMR Action Fund's investment.
We wrote this summary from public statements by Trellis Bioscience and its investors. It is not investment advice.
Trellis Bioscience in the News
Leadership Team
Executive officers and directors listed on Trellis Bioscience's Form D filed Oct 21, 2026.
Earlier filings also listed Thomas Lavin (director, last listed Nov 2011), Stote Ellsworth (executive officer and director, last listed Nov 2011), Somu Subramaniam (director, last listed Nov 2011), John Friedman (director, last listed Nov 2011), Markus Goebel (director, last listed Aug 2009), James Broderick (director, last listed Aug 2009) and Gerald McMahon (director, last listed Aug 2009).