Epsilogen, the global leader in immunoglobulin E (IgE) antibody therapeutics, has completed the acquisition of Boston-based TigaTx, a biotechnology company specializing in engineered immunoglobulin A (IgA) antibodies. The transaction creates what the companies describe as the world's leading pan-isotype cancer antibody company, with the goal of pioneering innovative antibody therapeutics in oncology.
As a result of the acquisition, TigaTx becomes a wholly owned subsidiary of Epsilogen. Financial terms of the transaction have not been disclosed. Dr. Sonia Gulati, a Principal at Global BioAccess Fund, has joined Epsilogen's board of directors following the deal.
Strategic Rationale and Scientific Approach
The acquisition positions Epsilogen at the forefront of antibody isotype innovation in cancer therapy. While virtually all current cancer antibody therapeutics utilize the IgG isotype, the human immune system has evolved five main antibody isotypes (IgG, IgM, IgE, IgA, and IgD), each with distinct immunological functions.
"Nature has evolved five different antibody isotypes to perform specific biologic functions. Following the acquisition, Epsilogen is in a unique position with in-house deep expertise in three of these, IgE, IgA and IgG," explained Pete Finan, Epsilogen's Non-Executive Chairman and a General Partner at Epidarex Capital.
The combined company can now select the most appropriate antibody isotype for specific cancer types:
- IgE antibodies activate T cells and macrophages to "warm up" cold tumor microenvironments
- IgA antibodies activate neutrophils, which are highly abundant immune effector cells
- IgG antibodies provide conventional antibody functionality
Importantly, the merger enables Epsilogen to create hybrid antibodies that combine different isotype functions into single molecules with potentially enhanced potency and improved pharmacokinetic/pharmacodynamic profiles.
Tim Wilson, CEO of Epsilogen, emphasized the strategic value: "Combining the capabilities of Epsilogen with those of TigaTx gives us the ability to choose the most relevant isotype for a given cancer, whether a cold tumour environment we want to drive multiple immune effector cells into or leverage neutrophils. The transaction also facilitates the combination of different isotype functions into a single antibody molecule."
Enhanced Pipeline and Technology Platforms
The acquisition significantly strengthens Epsilogen's development pipeline. The company's lead candidate, MOv18 IgE, an anti-Folate Receptor α IgE antibody, is currently in a Phase Ib proof-of-concept trial for platinum-resistant ovarian cancer. Phase I data previously demonstrated the antibody to be safe and well-tolerated with preliminary signs of anti-cancer activity.
TigaTx contributes EPS 401 (formerly TIGA-001), an anti-EGFR IgA antibody, which is undergoing IND-enabling studies and scheduled to enter clinical trials in 2026. The combined company's earlier-stage pipeline includes additional IgE and IgA antibodies targeting various tumor antigens.
Beyond the clinical candidates, the merger brings together several proprietary technology platforms:
- IgEG antibodies that combine IgE and IgG functionality in a single molecule
- Bispecific IgEs and IgEGs capable of binding two different antigens simultaneously
- IgA 3.0, an engineered derivative of wild-type IgA with improved manufacturing characteristics
Scientific Foundation and Expertise
TigaTx's approach to engineered therapeutic IgA is based on pioneering work by Professor Jeanette Leusen at the Utrecht Medical Center in the Netherlands. The company has developed expertise in harnessing neutrophils, which are abundant immune cells capable of driving both innate and adaptive immunity against tumors.
Epsilogen has established itself as a leader in IgE-based cancer therapeutics, focusing on activating myeloid cells and T cells to enhance anti-tumor immune responses, particularly in immunologically "cold" tumor microenvironments.
"We are thrilled about the merger with Epsilogen and believe deeply in the potential of IgA and IgE-based therapies to transform cancer treatment. Together, we are advancing a new frontier in immunotherapy to bring innovative solutions to patients in need," said Dr. Sonia Gulati of Global BioAccess Fund.
Differentiated Mechanism of Action
The scientific rationale for exploring alternative antibody isotypes stems from their distinct mechanisms of action compared to conventional IgG antibodies. IgE and IgA antibodies engage different immune effector cells and pathways that may overcome resistance mechanisms seen with current therapies.
IgE antibodies primarily activate mast cells, basophils, and eosinophils, triggering potent inflammatory responses. In the cancer context, these responses can recruit and activate additional immune cells within the tumor microenvironment. IgA antibodies, meanwhile, primarily engage neutrophils through FcαRI receptors, potentially enabling more effective targeting of solid tumors where neutrophils are abundant.
The ability to combine these mechanisms through hybrid antibodies represents a novel approach that could address limitations of current cancer immunotherapies, particularly in solid tumors that remain challenging to treat.
Market Position and Future Outlook
With this acquisition, Epsilogen establishes itself as the only company with comprehensive expertise across multiple antibody isotypes for cancer therapy. This unique position could provide significant competitive advantages in developing next-generation antibody therapeutics.
The company will continue operating from its existing facilities, with TigaTx's Boston location becoming a U.S. subsidiary. The combined organization will leverage complementary scientific and development capabilities to advance its pipeline and explore new applications of its isotype technologies.
"We are excited to create the world's leading pan-isotype antibody company with the goal of bringing improved therapeutics to cancer patients," Wilson concluded. "We are looking forward to working with our new colleagues in Boston and creating additional opportunities in our pipeline."
