Epsilogen Ltd.

Epsilogen and TigaTx have not disclosed the financial terms of the deal. Credit: RealPeopleGroup via Getty Images. UK biotech Epsilogen has acquired US-based antibody developer TigaTx in a deal that collates work from the two companies’ alternative antibody isotopes for cancer. The move combines Epsilogen’s clinical focus on immunoglobulin E (IgE) antibodies with TigaTx’s work on immunoglobulin A (IgA), creating what the companies describe as a “pan-isotope” platform for oncology. The financial terms of the deal were not disclosed, but TigaTx will become a wholly owned subsidiary of Epsilogen as part of the transaction. While most approved antibody therapies – like Daiichi Sankyo and AstraZeneca’s Enhertu (trastuzumab deruxtecan) – are based on the immunoglobulin G (IgG) isotope, Epsiologen and TigaTx are developing candidates that harness alternative immune pathways. IgE antibodies used by Epsilogen are designed to activate immune responses through macrophages and T cells while TigaTX’s IgA platform targets neutrophils. “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,” said Epsilogen’s CEO Tim Wilson in the 7 April announcement. “The transaction also facilitates the combination of different isotype functions into a single antibody molecule,” Wilson added. Epsilogen’s lead asset, MOv18 IgE, is currently being investigated in a Phase Ib study (NCT06547840) in patients with platinum-resistant ovarian cancer. Earlier Phase I data showed MOv18 IgE to be safe and well tolerated with signs of clinical activity. MOv18 IgE is positioned as a potential rival to AbbVie’s Elahere (mirvetuximab soravtansine) because both candidates target the folate receptor alpha (FRa). Elahere secured full approval by the US Food and Drug Administration (FDA) in 2024 for the treatment of FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. According to GlobalData’s Pharma Intelligence Center, Elahere is projected to make $2bn in sales in 2030. GlobalData is the parent company of Pharmaceutical Technology. The acquisition adds a second clinical candidate to the pipeline in the form of TigaTX’s TIGA-001, an anti-EGFR IgA antibody that will now be developed under Epsilogen as EPS-401. The therapy is expected to enter the clinic next year. The broader pipeline includes additional IgE candidates targeting various tumour-associated antigens, all in preclinical stages. Both companies completed funding rounds in 2024. In September, Epsilogen raised £43.25m in a Series B funding round led by existing backers British Patient Capital, the Novartis Venture Fund, Epidarex Capital, the 3B Future Health Fund and ALSA Ventures. Meanwhile, TigaTx announced up to $35.5m in funding in December. The funds came from the Advanced Research Projects Agency for Health (ARPA-H) and a two-year small business innovation research (SBIR) grant from the National Cancer Institute (NCI) of the US National Institutes of Health (NIH).

The deal expands Epsilogen’s pipeline with TigaTx’s TIGA-001—to be renamed EPS 401—an anti-EGFR IgA antibody that is expected to enter the clinic next year.\n U.K.-based Epsilogen has bought Boston biotech TigaTx with the aim of creating “the world’s leading pan-isotype cancer antibody company.”Both companies are focused on immunoglobulin antibodies, with Epsilogen’s work orienting around IgE, while TigaTX has been hard at work developing IgA therapies.The deal, for which Epsilogen is not disclosing the financial details, will see TigaTx become a subsidiary of the London-based company.“We are excited to create the world’s leading pan-isotype antibody company with the goal of bringing improved therapeutics to cancer patients,” Epsilogen CEO Tim Wilson said in the April 7 release.“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,” Wilson added. “The transaction also facilitates the combination of different isotype functions into a single antibody molecule.”The deal expands Epsilogen’s pipeline with TigaTx’s TIGA-001—to be renamed EPS 401—an anti-EGFR IgA antibody that is expected to enter the clinic next year.Epsilogen already has a candidate in the clinic in the form of MOv18 IgE, which targets the folate receptor alpha antigen. While researchers discovered IgE antibodies all the way back in 1966, and biologics pioneers considered them at the birth of the biotech industry, Epsilogen claims its candidate is the world’s first IgE antibody to enter human trials. Data from a phase 1 trial of MOv18 IgE have produced early signs of clinical activity, according to Epsilogen, leading the biotech to move the asset into a phase 1b trial in patients with platinum-resistant ovarian cancer.Looking ahead, Epsilogen sees the deal as giving it the option to “mix and match IgE, IgA and IgG functionality into a single antibody molecule.”“Such hybrid antibodies have the potential to activate multiple compartments of the immune system as well as possessing improved PK/PD profiles,” the company explained in the release. “This is especially powerful in the light of the importance of the epitope in determining the clinical performance of antibodies.”In September, Epsilogen completed a 12.5 million pound sterling ($16 million) series B top-up to help fund the phase 1b study of MOv18 IgE. Previous backers Novartis Venture Fund, British Patient Capital, Epidarex Capital, 3B Future Health Fund and ALSA Ventures all returned for the latest raise.Meanwhile, TigaTx—with tech based on work by Professor Jeanette Leusen at the Utrecht Medical Center in The Netherlands—secured $33.5 million in funding last December from the U.S. Department of Health and Human Services’ Advanced Research Projects Agency for Health, along with a $2 million business grant from the National Cancer Institute.

LONDON & BOSTON--([BUSINESS WIRE](https://www.businesswire.com/))--**Highlights** * The acquisition combines IgA antibody assets and expertise of Boston-based TigaTx with Epsilogen’s assets and expertise in IgE to create the world’s leading pan-isotype cancer antibody company * Allows selection of the most appropriate antibody isotype for a given cancer, applying the unique mechanisms of action for each: * IgA activates neutrophils, a potent and highly abundant immune effector cell * IgE activates T cells and macrophages to warm up the tumour microenvironment (TME) * Facilitates combination of different isotype functions into single antibody molecules with enhanced potency and performance * Combined clinical-stage company benefits from a strong pipeline: * MOv18 IgE, an anti-Folate Receptorα IgE antibody, currently in a Phase Ib Proof of Concept trial in platinum-resistant ovarian cancer. Data from a Phase I trial found it to be safe and well tolerated with early signs of clinical activity * EPS 401 (formerly TIGA-001), an anti-EGFR IgA antibody with IND-enabling studies underway * Further IgE and IgA antibodies targeted to other validated cancer antigens * In addition to IgE, the combined company has three proprietary antibody platforms: * IgEG antibodies which combine IgE and IgG functionality into a single antibody molecule * Bispecific IgEs and IgEGs which can bind two different antigens simultaneously * IgA 3.0, an engineered derivative of wild type IgA with improved manufacturing profile * US based TigaTx becomes a wholly owned subsidiary of Epsilogen * Sonia Gulati of Global BioAccess Fund has joined Epsilogen’s board of directors * Financial terms of the transaction have not been released Epsilogen, the global leader in the development of immunoglobulin E (IgE) antibody therapeutics, today announces that it has completed the acquisition of TigaTx, Inc., a biotechnology company developing engineered immunoglobulin A (IgA) antibodies, to create the world’s leading pan-isotype cancer antibody company. As a result of the combination of these two privately held companies, US-based TigaTx becomes a wholly owned subsidiary of Epsilogen. Financial terms of the transaction have not been disclosed. Additionally, Dr Sonia Gulati, a Principal at Global BioAccess Fund has joined the Epsilogen Board of Directors. Commenting on the acquisition, **Epsilogen CEO Tim Wilson said:** _“We are excited to create the world’s leading pan-isotype antibody company with the goal of bringing improved therapeutics to cancer patients. 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. We are looking forward to working with our new colleagues in Boston and creating additional opportunities in our pipeline.”_ **Sonia Gulati PhD, a Principal at the Global BioAccess Fund said:** _“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.”_ **Pete Finan, Epsilogen’s Non-Executive Chairman and a General Partner at Epidarex Capital commented:** _“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. We very much look forward to the company turning this potential into innovative new medicines for cancer patients.”_ **Rationale: Creating the world’s leading pan-isotype cancer antibody company** The primary purpose of this transaction is to create the world’s leading pan-isotype antibody company with the goal of pioneering radically new antibody therapeutics in oncology. The acquisition not only gives Epsilogen the capability of selecting the appropriate antibody isotype for a given cancer, given the differentiated therapeutic mechanisms of each, but also allows it to mix and match IgE, IgA and IgG functionality into a single antibody molecule. Such hybrid antibodies have the potential to activate multiple compartments of the immune system as well as possessing improved PK/PD profiles. This is especially powerful in the light of the importance of the epitope in determining the clinical performance of antibodies. The human immune system has evolved five main antibody isotypes (IgG, IgM, IgE, IgA and IgD) which it can call upon depending upon the challenge faced. All cancer antibodies and antibody derivatives to date, and virtually all in clinical development, are based on the IgG isotype. IgG utilises the gamma chain constant region whereas antibodies of the IgE and IgA isotypes use the epsilon and alpha chain constant regions respectively; the variable regions of all wild type antibodies are structurally the same. IgE and IgA antibodies have distinct and potent immunological effector functions predominantly working through myeloid cells and neutrophils respectively. Each of these broad classes can bring about solid tumour destruction in a variety of preclinical models. The acquisition bolsters Epsilogen’s pipeline by adding EPS 401 (formerly TIGA-001), an anti-EGFR IgA antibody, scheduled to enter the clinic in 2026. MOv18 IgE is currently in a Phase Ib trial for treatment of platinum-resistant ovarian cancer (PROC). Phase I trial data previously showed the antibody to be safe and well tolerated with preliminary signs of anti-cancer activity. Epsilogen’s earlier stage pipeline also features a number of other IgE antibody candidates targeting a variety of tumour antigens. **About TigaTx** TigaTx is a biotechnology company developing engineered monomeric IgA neutrophil engagers to unleash the tumour killing power of neutrophils for cancer. The company's cutting-edge approach in engineered therapeutic IgA is based on pioneering work by Professor Jeanette Leusen conducted at the Utrecht Medical Center (Utrecht, The Netherlands). Based in Boston, MA, TigaTx is developing a pipeline of therapies to treat different cancer types. **About Epsilogen Ltd** Epsilogen is the world’s leading pan-isotype antibody therapeutic company for the treatment of cancer. It has unique and proprietary expertise in the discovery and development of IgE, IgA and IgG-based therapeutics with each isotype possessing differentiated immune effector function. IgE has significant activity against various tumour types by activating myeloid cells and T cells thereby warming up the tumour micro-environment (TME). IgA’s anti-cancer potential is mediated by the activation of neutrophils, highly abundant effector cells which drive innate and adaptive immunity. The distinct activity profiles of each isotype allow Epsilogen to select the most appropriate isotype for a given cancer. The company has also combined different isotypes into a single antibody molecule with enhanced functionality. Epsilogen’s lead product candidate, MOv18 IgE, is the first therapeutic IgE antibody to enter the clinic and encouraging data from a completed Phase I trial found it to be safe and well tolerated with early signs of clinical activity. Epsilogen has initiated a Phase Ib trial in platinum-resistant ovarian cancer patients. Find out more at [Epsilogen.com](https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fepsilogen.com%2F&esheet=54234498&newsitemid=20250406268542&lan=en-US&anchor=Epsilogen.com&index=1&md5=c1726cf4016165ecf5206d3fd9853bfb).