Novel microparticle-based immune response modifier shows broad effects against recurrent or metastatic cancer

Apr 22 2009

MIS416, a novel microparticle-based immune response modifier, demonstrated the ability to significantly reduce the number and size of metastatic tumors in preclinical mouse models of lung and breast cancers, Innate Therapeutics (formerly Virionyx Corporation) announced.

Research presented today at the American Association of Cancer Research (AACR) meeting in Denver, CO by researchers from the Auckland, NZ company and their colleagues at the David Geffen School for Medicine, University of California, Los Angeles showed that MIS416 significantly inhibited tumor growth and the formation of metastases when tested as a stand-alone agent. When administered as an adjunct to localized tumor irradiation, MIS416 also demonstrated synergistic activity against the recurrence of lung tumors. Moreover, in a therapeutic cancer vaccine model, MIS administered as a single agent significantly induced an anti-tumor cellular immune response without the reintroduction of previously harvested tumor antigens. This successful induction of adaptive immunity correlated with inhibition of tumor growth.

"On the basis of these findings, MIS416 appears to be a good candidate for clinical evaluation as an adjunct to existing cancer therapies such as surgery and radiation," said Gill Webster, Ph.D., chief scientific officer of Innate Therapeutics, who led the poster presentation. "In this clinical setting, MIS416 therapy may be able to contribute significantly towards limiting tumor reoccurrence or metastatic disease."

Immune response modifiers (IMRs) are agents that target the body's immune system to combat disease by mobilizing and expanding a broad range of intrinsic host defence mechanisms. Unlike first generation IMRs such as Toll-like receptor agonists or interferon alpha, each of which have a limited spectrum of activity and lack the ability to treat a broad range of malignant diseases, MIS416 acts on multiple pathways simultaneously to activate a broad range of innate immune cell types that are central to the development of innate and adaptive anti-tumor responses.

Innate Therapeutics noted that the company plans to shortly begin a Phase 1 clinical trial of MIS416 in New Zealand. "While this study will be the first formal clinical trial of MIS416 in humans, the drug has been used under compassionate release exemption to treat a small number of patients with chronic or life threatening illnesses including progressive multiple sclerosis and metastatic disease," said Simon Wilkinson, Innate Therapeutics' chief executive officer. "To date, MIS416 has shown itself to be safe and well tolerated in these patients. Extensive toxicity studies of the drug in animals have also shown excellent safety with those treated showing no adverse effects at doses up to 650 times in excess of doses likely to be used therapeutically in humans."

MIS416 is a novel 2nd generation, multi-modal IRM, comprising a microparticulate formation of naturally occurring, non-immunogenic, cytosolically active TLR-9 and NOD-2 agonists. Signaling pathways activated by these ligands act synergistically to activate a broad range of innate immune cell subsets that are central to the development of innate and adaptive immune responses.