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.
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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.
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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).
