Bay Area startup TRexBio has bolstered its 2024 Series B with an additional $50 million to fund the biotech’s clinical development in the burgeoning Treg space.
The biotech, founded in 2018 by SV Health Investors, will use the Series B extension to “allow for optionality going forward,” CEO Johnston Erwin said in an interview with
Endpoints News
. TRexBio could pursue an IPO, an M&A exit to a larger pharmaceutical maker, or stay independent, he said.
The funding TRexBio revealed Tuesday builds on an
$84 million Series B
disclosed in November 2024 and will support the advancement of TRB-061, which is in a
Phase 1a/b
trial. The investigational medicine is an agonist of TNFR2, a co-stimulatory receptor that is found on suppressive regulatory T cells in the skin and gut.
The regulatory T cells field got a major boost last year, when researchers were awarded the
Nobel Prize
in Physiology or Medicine for their work in this area, which has recently attracted investor interest at startups like
Zag Bio
and
RegCell
. But it hasn’t been entirely smooth sailing for startups:
Abata Therapeutics
shuttered shortly before the major scientific award was doled out, and
Sonoma Biotherapeutics
reduced its workforce this month.
The Nobel and clinical advancements helped drum up additional interest in TRex, Erwin said. His company, along with
Sonoma
,
GentiBio
and
Quell Therapeutics
, all have clinical programs with varying approaches to the Treg space.
Eli Lilly had also brought a TRex-derived asset called TRB-051 into the
clinic
in 2024 as part of a
$1.1 billion
biobucks-loaded pact.
Lilly, where Erwin was VP of corporate business development until 2021, is one of the investors in TRex. Also supporting TRex’s clinical-stage pipeline are Janus Henderson, Balyasny Asset Management, Affinity Asset Advisors, Alexandria Venture Investments, Polaris Partners and Avego BioScience Capital, among others. The venture arms of Johnson & Johnson and Pfizer are also backers of TRex.
TRex currently has about 60 employees and will grow closer to 75 as it gears up for additional clinical trials, Erwin said.
Other companies in the TNFR2 arena include
Odyssey Therapeutics
, which is in the preclinical stages of exploring a protein therapeutic for systemic lupus erythematosus, vitiligo and type 1 diabetes. Belgian Treg startup
Dualyx
also had plans in this field, but appears to have gone quiet.
TRex is homing in on atopic dermatitis for TRB-061’s first foray in the clinic. Atopic dermatitis has become one of the leading diseases addressed by the surge in investor and pharma interest in inflammation and immunology in recent years. The National Eczema Foundation said about 10% to 20% of children and 2% to 10% of adults globally have the condition.
With the new capital, TRex can also further develop TRB-071 and TRB-081 for undisclosed inflammatory and autoimmune diseases. Both will start Phase 1 testing in 2027, the startup said.