We believe HMPL-523 is a potential global first-in-class oral inhibitor targeting the spleen tyrosine kinase, or Syk, a key protein involved in B-cell signalling. Modulation of the B-cell signalling system has been proven to significantly advance the treatment of certain chronic immune diseases, such as rheumatoid arthritis. To date, only monoclonal antibody modulators, which seek to use the patient’s own immune system to treat the disease, have been approved. HMPL-523, as an oral drug candidate, may have important advantages over intravenous monoclonal antibody immune modulators in that small molecule compounds clear the system faster, thereby reducing the risk of infections from sustained suppression of the immune system. Moreover, other drug development companies have tried to design small molecule Syk inhibitors for the treatment of chronic immune diseases. However, no drug products targeting Syk have been approved to date due to severe off-target toxicity side effects, such as hypertension, as a result of poor kinase selectivity. HMPL-523 is a potent and highly selective oral inhibitor specifically designed to overcome these off-target toxicity issues.
We believe the market potential for a successful Syk inhibitor is substantial. For example, the estimated size of the global market for rheumatoid arthritis drugs was approximately $34 billion in 2014 and is projected to grow to approximately $45 billion in 2020. We currently retain all rights to HMPL -523 worldwide.