Therapeutics · Protein conjugation
Catena Biosciences
A UC Berkeley spinout that uses an engineered tyrosinase to weld two proteins together through their native amino acids, now aimed at antibody drug conjugates carrying more than one payload. The lead molecule is still preclinical.
A chemistry talk in a business school
In January 2020, on the second day of an entrepreneurship course at the Haas School of Business, a fifth year chemistry PhD student stood in front of a room of MBA students with a deck of reaction schemes.
“Good God! I came in with all of these graphs and charts and all this science, and I’m trying to present to a bunch of business majors, whose last chemistry class was likely freshman year of college,” Marco Lobba told Berkeley News eighteen months later.
One person was listening. Geo Guillen, a second year MBA, wanted work with a point to it. “Marco was speaking passionately about his discovery of a new protein conjugation technology. This protein, and that pH level,” he said. A year later the two launched Catena Biosciences with Matthew Francis, the Berkeley chemistry professor whose lab the work came out of.
The join that keeps failing
Nearly every targeted biologic has the same weak point: the bond. Catena’s 2024 poster states the problem. Over 90 percent of antibody drug conjugates in the clinic use a lysine amide bond or a cysteine maleimide bond. Amide bonds give heterogeneous mixtures. Maleimide bonds come apart in serum. Neither lets you hang two payloads on one antibody at defined positions.
The Francis lab had been chasing an alternative since 2004. In spring 2017 Lobba and colleagues found that tyrosinase, the enzyme that turns a cut apple brown, could do the activating step alone, converting an exposed tyrosine into a quinone that grabs a cysteine on the partner protein.
“A lot of times when you bring full-sized proteins together, reactions start to fail because the proteins interact with each other, they push each other away. And so, you actually can’t form the bonds anymore,” Francis told Berkeley News. “But this reaction goes so fast it has enough power to bring these very large objects together.”
The chemistry landed in ACS Central Science in 2020, Lobba first author, Jennifer Doudna and Francis senior authors. The reaction “occurs under mild aerobic conditions and has the rare ability to join full-size proteins in under 2 h.” A maleimide linked control vanished from human serum within seven days; the tyrosinase linked product survived.
Founders, and the first target
Lobba did his PhD jointly in the Francis and Doudna labs. Francis chaired the Berkeley chemistry department. Guillen brought the MBA. Berkeley’s technology transfer office lists seven inventors on the underlying work and records the company as founded in 2020.
The first target was autoimmunity, for personal reasons. “Autoimmune diseases are important to me because everyone on the founding team has been personally affected or directly connected to people that faced autoimmune diseases in their lifetime,” Lobba said in 2022. The pitch was immune retraining: attach a tolerated signal to tissue under attack and the attack may stand down.
The turn to oncology
In September 2021 the NIH funded that idea with an SBIR Phase I award of $299,379 from the diabetes and digestive and kidney diseases institute, for antigen specific treatment of thyroid autoimmune disease. It ran to September 2023. RePORTER shows no Phase II and no other federal award.
By 2023 the center of gravity had moved. In May the American Cancer Society investment arm BrightEdge gave Catena a Golden Ticket, a year of free space at Bakar Labs. In July the company hired Saurabh Johri from Bayer as chief business officer and Rick Kendall, formerly chief executive of ImmPACT BIO and research vice president at Kite Pharma, as chief scientific officer.
Data followed: posters at the San Antonio Breast Cancer Symposium in 2023 and 2024, a Berkeley showcase at the J.P. Morgan conference in January 2024, and AACR in 2024 and 2025. The 2024 poster describes CATB-101 as a HER2 targeted conjugate carrying a topoisomerase inhibitor and a tubulin inhibitor at a ratio of 2 plus 2, matching or beating trastuzumab deruxtecan in a HER2 low mouse model at half the payload load. By August 2025 Nature Reviews Drug Discovery listed CATB-101 among dual payload ADCs, this time as TROP2 targeted.
Where it stands in September 2026
The company is not dark. Its site was live on September 22, 2026. Lobba made the San Francisco Business Times 40 Under 40 in April 2025 and is on the agenda for the 17th World ADC in San Diego on October 13, 2026, in a session promising the first report on a non-human primate toxicity study of CATB-101. CatenaBio is a conference sponsor.
But the trail has thinned. The last press release is dated April 2024, the last listed publication April 2025. No Series A has been announced, though the May 2024 funding release said the extension set the stage for one. The contact page now warns that a fraudulent domain has been posting fake CatenaBio job listings.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Core chemistry | Lobba et al., ACS Central Science, Aug 2020. Shown on Cas9, where two attached peptides raised editing efficiency 20-fold. | Public record |
| Serum stability | Same paper: a maleimide coupled construct was undetectable in human serum at 7 days; the tyrosinase version survived. The company extends this to its branded C-Y Bond. | Public record |
| CATB-101 data | Company posters only. AACR 2024 poster 5797 and AACR 2025 poster 2887 report mouse efficacy and sub-nanomolar IC50 values against approved comparators. Not peer reviewed. | Company-stated |
| Independent confirmation | Nature Reviews Drug Discovery, Aug 2025: CATB-101, CatenaBio, TROP2, a TOP1 and a tubulin inhibitor, preclinical. Mewburn Ellis and OncologyPipeline also covered the 2025 poster. | Independent |
| Which antigen it hits | The 2024 poster says HER2. The 2025 poster, Nature Reviews Drug Discovery and the pipeline page say TROP2. OncologyPipeline listed it as HER2 by TROP2. No explanation published. | Differs across sources |
| Patents | Releases call the technology patented. The 2020 paper says the Regents of the University of California have patents pending on this use of tyrosinase. Justia lists no US patent naming Catena Biosciences as assignee. | Claim ahead of record |
| Federal funding | One award, 1R43DK131833-01, $299,379, NIDDK, Sep 2021 to Sep 2023. No Phase II. No NSF award. | Public record |
| Clinical and regulatory | No study on ClinicalTrials.gov. No FDA record. No investigational new drug filing announced. | Not found |
| Papers under the company name | PubMed affiliation searches return nothing. The three journal papers the company lists carry Berkeley affiliations; the 2023 one is a Berkeley and Merck collaboration. | Not found |
| Pharma partnerships | The partners page cites work with top pharmas and 25 conjugates from 10 starting proteins. No partner named. | Company-stated |
Read plainly: the chemistry is real, published in a strong journal and interesting enough that Merck co-authored a follow-up. The drug is not. Every CATB-101 number in circulation comes from a company poster, and the strongest independent mention confirms only that the molecule exists and is preclinical. The disclosed capital behind it is modest for a field where a rival raised $187 million in one round.
What to watch
- The October 13, 2026 World ADC session. Non-human primate toxicity data would be the first safety evidence in public.
- A Series A. The May 2024 release framed the seed extension as a bridge to one, and none has appeared in the 28 months since.
- A named pharma partner, after three years of claimed strategic interest.
- Any peer reviewed paper or IND filing carrying the company’s own affiliation.
In their words
“We discovered a new protein conjugation process that allowed us to build things like CRISPR base editors.”
Marco Lobba, co-founder and CEO, Bakar Labs, 2022 · Interview
“Autoimmune diseases are important to me because everyone on the founding team has been personally affected or directly connected to people that faced autoimmune diseases in their lifetime.”
Marco Lobba, Bakar Labs, 2022 · Interview
“Think of it almost like Pavlov’s dogs, or tricking children into eating their vegetables by covering them in cheese.”
Marco Lobba, Berkeley News, 2021 · Independent
“Our technology is better than the competition because we bypass a lot of the limitations that the industry has in attaching, or combining, proteins together.”
Geo Guillen, co-founder, Berkeley News, 2021 · Independent
“There are still so many areas of oncology that are just not being addressed today. Our technology really gives us the opportunity to do that for the first time.”
Marco Lobba, Bakar Labs, May 2023 · Independent
“It’s really important to make sure that when you’re dealing with people’s lives and their health, that we build these therapeutics following a principles-first approach.”
Marco Lobba, Bakar Labs, April 2025 · Interview
Related companies
Sources
- Public recordSite-Specific Bioconjugation through Enzyme-Catalyzed Tyrosine and Cysteine Bond Formation
- Public recordModification of Cysteine-Substituted Antibodies Using Enzymatic Oxidative Coupling
- Public recordNIH RePORTER award 1R43DK131833-01
- Public recordSEC EDGAR Form D searches, no results
- Public recordClinicalTrials.gov, FDA and Justia Patents searches, no records
- Public recordCatena Biosciences technology and inventor listing
- IndependentDual-payload ADCs move into first oncology clinical trials
- IndependentBerkeley startup aims to be a game changer in autoimmune disease therapy
- InterviewTenant Spotlight: Catena Biosciences
- IndependentARIZ and Catena Awarded Golden Tickets to Bakar Labs
- InterviewLobba and Lugo Named to SF Business Times 40 Under 40
- IndependentNext Generation ADCs at AACR25
- IndependentAACR 2025 preview, a surge in dual-payload conjugates
- IndependentLobba speaker page and Catena Bio sponsor page
- CompanyCatena Biosciences Expands Executive Leadership Team
- CompanyCatenaBio at the Berkeley Bio Startup Showcase
- CompanyAACR posters 5797 and 2887
- CompanyCatenaBio home, science, pipeline, news and contact pages
- CompanyCatenaBio Raises $2.35 Million in Seed Extension Round
- CompanyCatena Biosciences company listing
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
