Seven of the top biotech companies to know about in South San Francisco

South San Francisco is regarded as the birthplace of biotechnology, after Robert Swanson and Dr. Herbert Boyer founded biotech giant Genentech in 1976, eventually leading to other biotech and pharmaceutical companies basing themselves in the local area. Consequently, the region is now viewed as one of the major biotech clusters in the world. In this article, we discover seven biotech companies that proudly call South San Francisco their home.

3T Biosciences

• Technology: Immunotherapy
• Disease area: Oncology
• Recent news: Entered into second partnership with Boehringer Ingelheim

After being founded in 2017, 3T Biosciences debuted in 2022 with $40 million series A financing. As a company focused on immunotherapy, it is looking to change the future of treatment for solid tumors, as well as other immune-mediated diseases. By studying patient immune responses against cancer, it aims to discover the best immunogenic targets that can be generalized for multiple tumor indications and across patient populations. It pairs this with therapeutic development in an attempt to create transformative therapies.

The company uses its proprietary 3T-TRACE platform technology to identify novel shared T cell receptor (TCR) targets of productive immune responses against solid tumors and other diseases, and to comprehensively screen TCR and T cell receptor mimetic (TCRm) molecules for specificity and off-target cross-reactivities, in order to then potentially create tumor-specific, safer therapies that can be delivered at higher doses.

In January 2023, 3T Biosciences entered into a strategic collaboration and licensing agreement with German pharmaceutical company Boehringer Ingelheim to discover and develop next-generation cancer therapies to address high unmet needs in patients. Then, in January last year, the two companies entered into a second partnership focused on discovering and developing next-generation life-changing cancer immunotherapies.

Arsenal Biosciences

• Technology: Cell therapies
• Disease area: Oncology
• Recent news: Achieved milestone in BMS collaboration 

Arsenal Biosciences is a programmable cell therapy company focused on discovering and developing a pipeline of next-generation autologous T cell therapies to treat solid tumors. The company has a wholly owned pipeline of three product candidates, including its lead candidate, AB-2100, which is currently being tested in a phase 1/2 trial for recurrent clear-cell renal cell carcinoma. 

AB-2100 utilizes ArsenalBio’s CITE (CRISPR Integration of Transgenes by Electroporation) technology to engineer T cells to selectively target the tumor and overcome the suppressive tumor microenvironment. These engineering features will potentially enable the patient’s immune system to destroy clear-cell renal cell carcinoma cells without harming normal tissues. 

The South San Francisco biotech company has a longstanding collaboration with pharma giant Bristol Myers Squibb (BMS), after initially partnering in December 2020 to advance next-generation T cell therapies for the treatment of solid tumors. The two companies achieved their latest milestone in January 2025, whereby BMS exercised its exclusive license option for ArsenalBio’s AB-4000 series, the lead collaboration program generated under the original agreement. 

Furthermore, in September 2024, Arsenal Bio raised $325 million in series C financing in what was one of the year’s largest biotech funding rounds.

Calico Life Sciences 

• Technology: Anti-aging therapies
• Disease area: Age-related diseases
• Recent news: Received Fast Track Designation for ABBV-CLS-628

Founded by Alphabet (the parent company of Google), Calico Life Sciences is a biotech company based in South San Francisco focused on the process of aging. It wants to find solutions that will help people live longer and healthier lives. It uses academic research and cutting-edge medical technology to answer biological questions surrounding how humans age and to devise interventions to help people lead longer lives, discovering new targets and developing first-in-class therapies for age-related diseases.

The company’s approach has led to a significant collaboration with AbbVie, in which AbbVie provides scientific and clinical development support and lends its commercial expertise to lead future development and commercialization activities. Through this collaboration, Calico is developing multiple candidates, including ABBV-CLS-628, for the treatment of Autosomal Dominant Polycystic Kidney Disease (ADPKD), which was granted Fast Track Designation by the U.S. Food and Drug Administration (FDA) earlier this month. It is currently being tested in a phase 2 trial. 

Calico also recently entered into an agreement with Chinese biotech Mabwell Bioscience for the rights to IL-11 directed therapeutics, including 9MW3811, a phase 1 monoclonal antibody (mAb).

Cartography Biosciences

• Technology: Antibody therapies
• Disease area: Oncology
• Recent news: Raised $67 million in series B funding round

Cartography Biosciences is focused on advancing an innovative pipeline of T-cell engaging bispecific and multi-specific antibody therapeutics that target novel and highly specific tumor antigens. To help with this, the company leverages petabytes of proprietary data, along with insights from machine learning and artificial intelligence (AI). It has two platforms, ATLAS and SUMMIT, which are powered by a fully integrated dataset spanning hundreds of thousands of cell states across the healthy body and large-scale profiling of individual cells from patient tumors.

The company’s lead program, CBI-1214, is a T-cell engager molecule that targets LY6G6D, an emerging and highly specific tumor antigen for treating colorectal cancer. This target, which has minimal expression on healthy cells, is uniquely expressed within the microsatellite stable (MSS) and microsatellite instability-low (MSI-L) subtypes of colorectal cancer, which represent the vast majority of colorectal cancer patients. Cartography’s candidate also has protein engineering features that are specifically designed to optimize anti-tumor activity.

In May 2024, the South San Francisco biotech company announced that it had entered into a strategic collaboration with Gilead to discover and develop therapies for patients with triple-negative breast cancer (TNBC) and the most common form of non-small cell lung cancer (NSCLC), adenocarcinoma.

Meanwhile, earlier this month, the company raised $67 million in series B financing, which the company said will help support the advancement of CBI-1214 into the clinic and the continued acceleration of additional oncology programs generated from its ATLAS and SUMMIT platforms. 

CytomX Therapeutics 

• Technology: Masked biologics
• Disease area: Oncology
• Recent news: Priced a $100 million underwritten offering 

Focused on developing novel conditionally activated, masked biologics designed to be localized to the tumor microenvironment, CytomX Therapeutics has a novel pipeline of candidates across multiple treatment modalities, including antibody-drug conjugates (ADCs), T-cell engagers, and immune modulators such as cytokines.

The company’s current clinical-stage pipeline includes CX-2051 and CX-801. CX-2051 is a masked, conditionally activated ADC directed toward epithelial cell adhesion molecule (EpCAM), armed with a topoisomerase-1 inhibitor payload. This has potential applicability across multiple EpCAM-expressing epithelial cancers, including colorectal cancer, and was discovered in collaboration with ImmunoGen. Meanwhile, CX-801 is a masked interferon alpha-2b PROBODY cytokine with broad potential applicability in traditionally immuno-oncology sensitive, as well as insensitive (cold) tumors. The candidates are in phase 1 trials for advanced colorectal cancer and metastatic melanoma, respectively.

CytomX’s latest financing came in May 2025, when it priced a $100 million underwritten offering. The company has also established strategic collaborations with multiple leaders in oncology, including Amgen, Astellas, Bristol Myers Squibb, Regeneron, and Moderna.   

Genentech

• Founded: 1976
• Disease areas:  Oncology, immunology, neuroscience, metabolism, infectious disease, and ophthalmology
• Recent news: Received FDA approval for Gazyva for the treatment of lupus nephritis

Regarded as an industry giant, Genentech is extremely well known in the biotech industry, having been founded more than 40 years ago in 1976. The company became a member of the Roche Group in March 2009, where the two companies combined their pharmaceutical operations in the U.S. as part of the agreement, meaning Genentech’s South San Francisco headquarters now serves as the headquarters for Roche’s pharmaceutical operations in the U.S. 

Genentech focuses on a wide range of therapeutic areas, including oncology, immunology, neuroscience, metabolism, infectious disease, and ophthalmology. Its clinical pipeline is currently composed of dozens of investigational molecules covering all of these therapeutic areas.

It also has multiple approved products, such as Gazyva, which was just given the green light by the FDA on October 20 for the treatment of lupus nephritis. Following four initial doses in the first year, Gazyva can be administered twice yearly, offering an effective and potentially more convenient treatment option than traditional targeted therapies. 

Some of Genentech’s other approved therapies include Activase, to treat patients with acute ischemic stroke, Esbriet, to treat people with idiopathic pulmonary fibrosis (IPF), and OCREVUS, to treat relapsing forms of multiple sclerosis (MS) and primary progressive MS. 

Vistagen

• Technology: Pherines
• Disease area: Mental health
• Recent news: Stated that it is on track to deliver topline phase 3 results of fasedienol later this year

Vistagen is committed to improving mental health by developing an innovative pipeline of central nervous system (CNS) medications to try and establish a new standard of care in the treatment of anxiety, depression, and other CNS disorders. 

Vistagen’s pipeline includes five clinical-stage product candidates, including its lead candidate fasedienol. Each candidate is an investigational agent belonging to a new class of drugs known as pherines. Pherines are administered as low microgram dose level nasal sprays and are designed with a novel mechanism of action that activates chemosensory neurons in the nasal cavity and can beneficially impact key neural circuits in the brain without systemic uptake or direct activity on CNS neurons in the brain.

In August 2023, the mental health company announced positive topline results from its phase 3 trial of fasedienol nasal spray for the treatment of social anxiety disorder. The trial met its primary endpoint: fasedienol demonstrated a statistically significant difference in the average Subjective Units of Distress Scale (SUDS) score during a public speaking challenge compared to placebo. 

In June this year, Vistagen said that it was on track to deliver topline data from its PALISADE phase 3 program, which is also evaluating fasedienol for the acute treatment of social anxiety disorder, in the fourth quarter of this year, while topline results for its PALISADE-4 phase 3 trial are expected in the first half of 2026.

South San Francisco: A major biotech hub

Nowadays, South San Francisco is home to one of the major biotech clusters in the world, competing with the likes of Massachusetts and North Carolina, with over 250 biotech companies having offices or research and development (R&D) facilities located there, including big names like Genentech, AstraZeneca, and Johnson & Johnson. Overall, it is estimated to have 12 million square feet of biotech space forming the anchor of South San Francisco’s economy, with a further 3.5 million square feet of biotech space currently under construction.

The region’s proximity to Silicon Valley plays a big part in its attraction for many biotechs, enabling Silicon Valley healthcare entrepreneurs and researchers to easily and efficiently collaborate with companies. Additionally, nearby universities like the University of California, San Francisco, Stanford University, and the University of California, Berkeley provide a large talent pool for biotechs to take full advantage of.