Southern California has long been known for its beaches and biotech, and nowhere is the region’s innovation more evident than in its antibody ecosystem. From San Diego’s wet labs to Pasadena’s protein engineers, the area has become a proving ground for companies blending creativity, capital, and clinical progress.

At BiopharmIQ, we’ve tracked more than a hundred SoCal bio/pharma's developing antibody-based drugs, and we’ve handpicked 10 companies to watch in 2025, chosen for their scientific breakthroughs, fresh financings, and clinical catalysts.

👉🏻 Explore the List of 115+ Antibody Companies in Southern California

Timberlyne Therapeutics — San Diego (Private)

Focus: Anti-CD38 Monoclonal Antibody (CM313)

Highlight: Launched with a $180M Series A

Timberlyne burst onto the scene with a powerful start, $180 million in Series A financing to develop CM313, a next-generation anti-CD38 monoclonal antibody targeting autoimmune diseases and cancers. Licensed from Key Med Biosciences, CM313 has shown impressive clinical activity and could redefine treatment for immune thrombocytopenia and lupus, putting Timberlyne at the forefront of antibody innovation.

Rakuten Medical — San Diego (Private)

Focus: Antibody–IR700 Photoimmunotherapy

Highlight: Global Phase 3 Expansion

Rakuten Medical’s Alluminox™ platform fuses antibodies with light-sensitive dyes, enabling precise photoimmunotherapy that kills tumor cells upon activation. Its Phase 3 program combining ASP-1929 with pembrolizumab has expanded internationally, marking a bold step for this antibody–dye conjugate pioneer.

Arialys Therapeutics — San Diego (Private)

Focus: Neuro-Autoantibody Therapies

Highlight: First-in-class approach in neuroimmunology (Active Phase 2)

Arialys is bridging neuroscience and immunology with ART5803, an antibody designed to neutralize anti-NMDAR autoantibodies involved in psychiatric and cognitive disorders. By targeting autoimmune responses within the brain, Arialys is redefining what antibody therapies can achieve in neurodegenerative and neuropsychiatric diseases.

Abcentra — Los Angeles (Private)

Focus: Cardiovascular Inflammation

Highlight: Phase 2b FORTIFY trial underway

Abcentra is tackling one of medicine’s toughest frontiers: cardiovascular inflammation. Its lead antibody, orticumab, targets oxidized LDL (oxLDL) to reduce inflammation following heart attacks, a first-in-class mechanism that could rewrite the playbook for post-MI care.

Candid Therapeutics — San Diego (Private)

Focus: Autoimmune Antibody Therapeutics

Highlight: Phase 1b Lupus Trial Initiated

Candid Therapeutics is conducting a Phase 1b multicenter trial for Cizutamig, an antibody designed to restore immune balance in patients with systemic lupus erythematosus (SLE). The trial marks a pivotal step for the company’s precision-immunology pipeline and adds new momentum to Southern California’s autoimmune antibody cluster.

Inmagene Biopharmaceuticals (ImageneBio) — San Diego (Public)

Focus: OX40 Inhibitory Antibody

Highlight: $75M raise + Nasdaq listing (IMA)

Following its merger with Ikena Oncology, Inmagene rebranded as ImageneBio (Nasdaq: IMA) and secured $75 million in financing to advance IMG-007, an OX40 antibody for atopic dermatitis. This move propels the company into late-stage development and establishes it as a serious contender in immunology antibody therapeutics.

Cidara Therapeutics — San Diego (Public)

Focus: Drug-Fc Conjugates (DFCs)

Highlight: BARDA partnership for flu prevention

Cidara’s Cloudbreak® platform creates Drug-Fc Conjugates (DFCs), a new class of antibodies that combine Fc immune functions with antiviral activity. With BARDA support exceeding $300 million, its lead candidate CD388 is advancing toward late-stage development for long-acting influenza prevention, a standout example of translational antibody science.

Xencor — Pasadena (Public)

Focus: Bispecific Antibody Engineering

Highlight: Phase 1 data for XmAb819

Xencor remains a cornerstone of antibody engineering. With Phase 1 data emerging for XmAb819 (ENPP3 × CD3) in renal cell carcinoma, the company continues to showcase the power of modular bispecific design and Fc innovation.

BioAtla — San Diego (Public)

Focus: Conditionally Active Biologics (CABs) and ADCs

Highlight: SITC 2025 updates

BioAtla’s CAB technology enables antibodies to activate only under tumor-specific conditions, offering precision with minimal off-target toxicity. With BA3011 and BA3021 in the clinic and new data expected at SITC 2025, BioAtla remains one of the top ADC developers on the West Coast.

Avidity Biosciences — San Diego (Public)

Focus: Antibody–Oligonucleotide Conjugates (AOCs)

Highlight: AOC technology and recent Novartis acquisition

Avidity has long been recognized for merging antibody targeting with RNA precision through its AOC platform. At the time of this analysis, Avidity was an independent biotech advancing multiple clinical programs; since then, Novartis has announced its acquisition of the company, a move that underscores the strategic and scientific value of its antibody-based delivery technology.

This transition highlights how Southern California’s antibody innovators continue to attract global pharma attention.

Closing Thoughts

From La Jolla’s neuroimmune startups to Pasadena’s bispecific innovators, these 10 companies represent the cutting edge of antibody R&D. Southern California’s antibody landscape isn’t just growing, it’s transforming medicine, one binding site at a time.

For business development and sales teams, the antibody landscape in Southern California offers more than scientific innovation; it’s a map of opportunity. Each of these companies represents a potential partner, customer, or collaborator at different stages of growth, from seed-funded startups to publicly listed leaders.

Through BiopharmIQ, users can:

• Identify emerging antibody developers before they make major headlines, using live updates on funding, leadership changes, and trial activity.

• Segment opportunities by technology type, such as ADCs, bispecifics, or conjugate platforms, to focus outreach on the most relevant prospects.

• Track company momentum through integrated clinical and financial signals, helping BD and marketing teams prioritize warm leads.

• Access verified decision-maker contacts, enabling faster and more targeted communication.

In short, BiopharmIQ helps teams move beyond static lists, turning industry discovery into actionable engagement. The Southern California antibody ecosystem is evolving quickly; our platform ensures you’re not just observing it, but connecting with it in real time.

And for those driving the next breakthrough right here in California…

🎃 Halloween Bonus: BiopharmIQ is offering a 20% discount on platform access for California-based biotech and pharma companies, because even antibodies deserve a treat!

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Article History:

10/29/25 MD, DG

Not legal, investing, or tax advice.