title: Spleen tyrosine kinase inhibitors: a review of the patent literature 2010 - 2013.
abstract: BACKGROUND
  The non-receptor tyrosine kinase, spleen tyrosine kinase (Syk), is primarily expressed in haematopoietic cells and appears to be particularly important in B cells. Syk is involved in signal transduction processes and appears to regulate allergic, inflammatory and autoimmune responses. It also appears to play a significant role in the development of haematological malignancies. Inhibitors of Syk are potentially useful in treating asthma, rheumatoid arthritis, lupus, chronic lymphocytic leukaemia and lymphomas.
  
  
  METHODS
  This article reviews the increasing number of patent filings between 2010 and 2013 claiming Syk inhibitors and focuses on the multiple structural classes of Syk inhibitors disclosed. It also comments on recent developments with Syk inhibitors, both clinical results and licensing deals.
  
  
  CONCLUSIONS
  The increased interest in the identification of Syk inhibitors has seen a sharp increase in patent filings claiming such compounds. However, the number of these is well below that of filings relating to other pro-inflammatory kinases (p38, JAK). These filings have also claimed an increasingly diverse range of chemical classes moving away from the 2,4-diaminopyrimidine motif present in drugs such as fostamatinib and PRT-06207. Many of the claimed compounds are Syk inhibitors with potencies considerably better than fostamatinib. However, good kinase selectivity is also likely to be essential if a Syk inhibitor is to prove useful enough to emulate the JAK inhibitor tofacitinib in gaining marketing authorisation. Recent clinical failures with Syk inhibitors are expected to result in a decrease in the rate of patent filings claiming Syk inhibitors.
authors.affiliation: Norman Consulting , 18 Pink Lane, Burnham, Bucks, SL1 8JW , UK peter.norman2@btinternet.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Norman
mesh_terms: D000818:Animals; D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors*; D010330:Patents as Topic; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D013154:Spleen / Q000187:drug effects / Q000201:enzymology*; D000072377:Syk Kinase
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D047428:Protein Kinase Inhibitors; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase