Acetylon has developed a pipeline of optimized, orally administered, HDAC selective compounds representing several, chemically distinct and separately patentable chemical “scaffolds” or families. Acetylon’s first clinical candidate, the selective HDAC6 inhibitor ricolinostat (ACY-1215), is targeted for the treatment of hematologic and solid tumor cancers and is currently being evaluated in several clinical trials for the treatment of relapsed or refractory multiple myelomaand a Phase 1b trial for the treatment of relapsed or refractory lymphoma.
Acetylon is also exploring in laboratory studies several additional potential cancer indications, including certain leukemias and solid tumors, where selective inhibition of HDAC6 or HDAC1/2 is anticipated by Acetylon to potentially provide a favorable anti-cancer effect as a single agent and/or in combination with existing anti-cancer agents. Scientists at Acetylon and at collaborating academic institutions have observed promising preclinical results with both ricolinostat and ACY-241 in combination with taxanes, a widely utilized class of anti-cancer drugs, in preclinical models of solid tumors including breast, lung, ovarian and pancreatic cancers. Acetylon is planning to initiate a further Phase 1b clinical trial in patients with solid tumors that can be treated with taxanes.
Experiments also suggest that selective HDAC6 inhibitors including ricolinostat and ACY-241 could have potential a roles in the exciting field of immuno-oncology, and additional clinical trials are being planned to explore the anti-cancer activity of Acetylon’s drug candidates in combination with proven immunotherapeutic drugs such as immune checkpoint inhibitor monoclonal antibodies.
Acetylon is currently advancing other orally bioavailable, highly selective, potent inhibitors of HDAC6 into late stage preclinical development. Such compounds have demonstrated biological activity in the areas of autoimmunity and neurodegeneration, as well as neurologic and other diseases in laboratory studies.
Neurodegenerative diseases and autoimmune diseases each represent a major, growing public health problem. In the U.S., rheumatoid and osteo-arthritis, systemic lupus erythematosus, inflammatory bowel disease and severe psoriasis affect millions of patients, and there are an estimated 400,000 cases of multiple sclerosis. Most currently available treatments for these diseases are biologic drugs, which are typically costly, must be administered by injection, and have been associated with significant risks including FDA “black box warnings” for opportunistic infections and secondary cancers. There is a clear need for new, targeted oral drugs that demonstrate effectiveness in slowing or reversing the progression of autoimmune disease and exhibit improved safety and administration profiles.
Neurodegenerative disorders represent a major unmet clinical need, affecting many millions of patients in the U.S. alone. Treatment options are limited and have, at best, limited benefit in slowing disease progression. There is a clear requirement for new, targeted oral drugs that demonstrate effectiveness in slowing or reversing the progression of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s, Lou Gherig’s (ALS), and other related disorders.
HDAC inhibitors have been demonstrated in the scientific literature to have activity in models of both of these categories of human disease. Acetylon is actively engaged in research and development of proprietary, oral, selective HDAC inhibitor compounds to address these major areas of unmet clinical need.
Acetylon is also pursuing development of selective HDAC inhibitors for other disease indications including major genetic diseases such as sickle cell disease and thalassemia major (beta-thalassemia) and parasitic diseases such as malaria.
The induction of fetal hemoglobin (HbF) is an established therapeutic strategy for sickle cell disease that also holds potential for the treatment of beta-thalassemia. HDAC inhibition has been shown to induce HbF, however, clinical development of non-selective HDAC inhibitors has been limited due to off-target side effects. Selective HDAC1/2 inhibition represents a novel treatment approach that could potentially represent a better-tolerated treatment option for patients with sickle cell disease and beta-thalassemia.
Acetylon has successfully demonstrated the potent inhibition of the life cycle of the most common severe form of malaria (plasmodium falciparum) in human blood cells without appreciable toxicity to white blood cells with selective HDAC inhibition.