French biotech ErVimmune raises €17M to advance off-the-shelf cancer vaccine targeting HERVs

The financing came from an international investor syndicate, which included French Seventure and Singaporean SPRIM Global Investments. Moreover, the funding is expected to allow ErVimmune to unlock further non-dilutive support from Bpifrance and France’s 2030 investment program, which have been supporting the company’s development.

HERVs: A new frontier in cancer immunotherapy

The Lyon-based biotech’s lead candidate, ErVac01, is a vaccine containing epitopes for the human endogenous retroviruses (HERVs) intended to treat “cold” tumors such as triple-negative breast cancer and ovarian cancer, which typically respond poorly to checkpoint inhibitors.

HERVs are ancient viral DNA sequences embedded in the human genome. Under normal conditions, they are epigenetically silenced, but cellular stress, such as the high proliferative pressure seen in cancer cells, can lead to their reactivation and expression. Although HERVs are not specifically expressed in cold tumors, “Our development plan has prioritized cold tumors to establish a proof-of-concept in high medical need indications,” said Nathalie Donne, ErVimmune CEO, in an email to European Biotechnology Magazine. “We expect to evaluate, later, our vaccine in other cancers, such as lung adenocarcinoma or melanoma,” she said.

HERVs provide a rich source of targetable antigens, particularly in tumors with low or moderate mutational burden. The immune system recognizes HERV-derived antigens as foreign, “virus-like” proteins, offering promising targets for the development of novel cancer vaccines, such as ErVac01, and T cell–based therapies.

ErVimmune also has a T cell-based therapy program in the discovery stage. “This program is still in research with an academic collaboration to optimize T cell engineering,” said Donne.

Off-the-shelf, global coverage

Importantly, ErVac01 is designed to work as an off-the-shelf, ready-to-use vaccine, independent of the HERVs expressed in each patient. The company states that the asset is a heterologous vaccine formulation containing a collection of HERV-derived epitopes covering the majority of the worldwide population in terms of HLA alleles.

HLA alleles are proteins on the surface of cells that present epitopes to T cells, enabling the immune system to recognize and respond to threats. These alleles vary across populations due to genetic diversity. Donne told European Biotechnology Magazine that, based on analyses using the Immune Epitope Database (IEDB) resource, the ErVac01 vaccine formulation includes epitopes predicted to provide coverage of >95 % in Europe, >80 % in Asia, >88 % in North America, >71 % in South America, and 50–60 % in Africa.

At the forefront of HERV-based therapeutics

The field of HERV-targeted therapies is still in its early stages, and ErVimmune is one of the pioneers. California-based T-Cure Bioscience is investigating a T-cell receptor (TCR)-based cell therapy targeting a HERV-derived antigen in a phase 1 clinical trial in renal cell carcinoma. The most recent update from the company was shared in June 2023, and its clinical trial (NCT03354390) remains active but not recruiting.

HERVolution Therapeutics, with headquarters in Denmark and New York, is another biotech targeting HERVs, but its goal is to treat diseases of aging. Still in preclinical stage, the company sees HERVs as “therapeutic allies.” Its proprietary engineering platform aims to develop off-the-shelf immunotherapies targeting HERVs implicated in aging-related diseases, with an initial focus on cancer, metabolic disorders, and longevity.

Regarding ErVimmune, “First-in-human [clinical trial for ErVac01 in cold tumors] will be conducted in Europe with an expected timeline of S1 2027,” said Donne. And she added that the company is still looking for additional funding to further support ErVac01 development.