Immune stimulating antibody conjugate
An Immune stimulating antibody conjugate is a mAb that conjugates an antibody to an immune-stimulatory agent.[1] They have been used in targeting tumors in mouse models, particularly to turn "cold tumors into hot ones".[2] Immune stimulating antibody conjugates work by activating dendritic cells within the tumor,[3] and are capable of being delivered systemically.[4] With some patients being resistant to checkpoint inhibitors, immune stimulating antibody conjugates may be able to harness an immune response generated through the stimulation of toll-like receptors.[3] In mice models, "dendritic cells (DCs) [were able] to internalize tumor antigens and subsequently activate tumor-reactive T cells"; this has been used "to treat autologous and autochthonous tumors successfully".[5]
Example
An immune stimulating antibody conjugate comprising a TLR7/TLR8 dual agonist conjugated to antibodies targeting at human epidermal growth factor receptor 2(HER2) has been developed.[6] Mechanically, immune stimulating antibody conjugates required tumor antigen recognition, FcγR-dependent phagocytosis and TLR-mediated activation to drive tumor killing by myeloid cells and subsequent T-cell-mediated antitumor immunity.
References
- "Study to Determine Safety and Dose of NJH395 in Non-breast HER2+ Advanced Cancer". Smart Patients. 2018. Retrieved 9 June 2019.
Immune stimulator antibody conjugate (ISAC), consisting of a monoclonal antibody which targets HER2 conjugated to an immune-stimulatory agent.
- Vinluan F (5 February 2019). "Bolt Bio Bags $54M for Drugs that Turn the Heat Up on "Cold" Tumors". Xconomy. Retrieved 9 June 2019.
The company’s therapies consist of a tumor-targeting antibody that homes in on tumors and is paired with an immune stimulant that turns cold tumors into hot ones. In preclinical testing, the company says that these immune-stimulating antibody conjugates eliminated tumors.
- Grover N (1 April 2019). "AACR: Bay Area biotech bets on antibodies armed with immuno-stimulant to fight checkpoint-resistant cancers". Endpoints News. Retrieved 9 June 2019.
The researcher, Stanford’s Ed Engleman, has built on his research into dendritic cells — which are considered ‘sentinels’ of the immune system as they are responsible for inducing immune T-cell responses — to develop this Immune-Stimulating Antibody Conjugate (ISAC) technology, which was unveiled by exclusive licensee Bolt Biotherapeutics at the American Association for Cancer Research (AACR) Conference on Monday. “What Bolt has come up with is to wake up dendritic cells within the (tumor) microenvironment, and we were able to do this in a targeted way,” said David Dornan, senior VP of research, in an interview with Endpoints News ahead of the conference. Many patients are refractory to checkpoint inhibitors because there are a number of immunosuppressive factors present in their tumor microenvironment, and so researchers have been trying to harness different molecules to stimulate the immune system, one of which are toll-like receptor (TLR) agonists — specialized proteins that initiate an immune response to foreign pathogens or, in this case, cancer cells. But the challenge of delivering these adjuvants is that they must be delivered intratumorally, because if they were administered systemically — say orally or intravenously — they can become toxic as immune cells across the body are activated and the impact is not targeted, Dornan emphasized.
- "Week In Review: China Resources And Charoen Pokphand Join To Launch $300 Million Life Science Fund". Seeking Alpha. 10 February 2019. Retrieved 9 June 2019.
Bolt is developing systemic immune system treatments to provide immunity-based therapies for cancer. The company will use the funds to advance its lead Boltbody™ Immune-Stimulating Antibody Conjugate (ISAC) into the clinic.
- Carmi Y, Spitzer MH, Linde IL, Burt BM, Prestwood TR, Perlman N, et al. (May 2015). "Allogeneic IgG combined with dendritic cell stimuli induce antitumour T-cell immunity". Nature. 521 (7550): 99–104. Bibcode:2015Natur.521...99C. doi:10.1038/nature14424. PMC 4877172. PMID 25924063.
- Ackerman SE, Pearson CI, Gregorio JD, Gonzalez JC, Kenkel JA, Hartmann FJ, et al. (January 2021). "Immune-stimulating antibody conjugates elicit robust myeloid activation and durable antitumor immunity". Nature Cancer. 2 (1): 18–33. doi:10.1038/s43018-020-00136-x. PMC 9012298. PMID 35121890.