
UC San Diego spinout awarded up to $15M for nanosponge designed to soak up sepsis-causing toxins
CARB-X, a global partnership looking to spur the development of new antibacterial drugs, is awarding Cellics Therapeutics $3.94 million to do what president and CMO Steve Chen calls “looking at traditional drug development upside down.”
Instead of going after a target directly — in this case bacterial toxins and inflammatory cytokines that cause sepsis — Cellics researchers “flip it around” to examine the host cells being attacked. The UC San Diego spinout then creates what it calls “nanosponges” — nanoparticles cloaked in the fragments of macrophage cell membranes. Chen says the “sponges” are designed to trap the sepsis-causing endotoxins and cytokines on their cell membranes, neutralizing them.
The concept was pioneered by UC San Diego nanoengineering professor Liangfang Zhang, who founded Cellics in 2014. The San Diego-based biotech has several macrophage and red blood cell nanosponges in the pipeline, including its lead candidate for MRSA pneumonia. The CARB-X grant, though, is for Cellics’ macrophage candidate CTI-111, aimed at sepsis caused by drug-resistant Gram-positive and Gram-negative bacteria.
“Sepsis in general has been a very difficult disease to treat,” Chen said. The condition is caused by the body’s response to an infection, and affects roughly 1.7 million adults in the US each year, according to the CDC.
The CARB-X grant will be used to scale up production of the nanosponges, and develop an animal model for testing. Cellics is eligible for another $11.05 million down the road, bringing the grant total to $15 million if milestones are met. That amount would carry the candidate all the way through a Phase I study, Chen said.
Cellics plans on bringing the sepsis candidate to the clinic in the next two years. It would be administered by IV in combination with antibiotics and other medicines. The biotech’s MRSA pneumonia candidate, CTI-005, should enter human studies next year, according to Chen.
The CMO believes the nanosponges could also be used for a range of other illnesses, from inflammatory bowel disease to Covid-19. The concept is the same — instead of latching onto a host cell, the virus would latch on to a nanosponge and become neutralized. Chen said to imagine throwing a dart at a pebble: You aren’t very likely to hit it. But if the pebble is scattered into a bunch of tiny particles (aka the nanosponges), the dart (the virus) is likely to hit one. The company may one day have an oral formulation, or even a topical one, he added later.

Between 2016 and 2022, CARB-X has pledged to pump up to $480 million into the development of new antibiotics, vaccines, rapid diagnostics and other products. Big Pharma has retreated from the field, fraught with cheap generics and poor financial returns. Back in January, WHO director-general Tedros Adhanom Ghebreyesus said the threat of antimicrobial resistance has never been more immediate.
“Sepsis is a leading cause of death around the world that is made worse by the lack of effective preventatives and treatments for drug-resistant bacterial infections. Effective treatments are urgently needed,” CARB-X R&D chief Erin Duffy said in a statement.