Pharmacyclics is getting a priority review of its blood cancer treatment by federal regulators. A priority review shortens a drug evaluation by the U.S. Food and Drug Administration from 10 months to six. The acceptance of the application triggers a $75 million milestone payment to Pharmacyclics from Johnson & Johnson’s Janssen unit.
Ibrutinib (USAN), also known as PCI-32765, is an experimental drug candidate for the treatment of various types of cancer. It is an orally-administered, selective and covalent inhibitor of the enzyme Bruton tyrosine kinase (Btk). Ibrutinib is currently under development by Pharmacyclics, Inc and Johnson & Johnson’s Janssen Pharmaceutical division for B-cell malignancies including chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B-cell lymphoma, and multiple myeloma.. Ibrutinib was first designed and synthesized at Celera Genomics by Zhengying Pan, who along with a team of chemists and biologists reported in 2007 a structure-based approach for creating a series of small molecules that inactivate BTK through covalent binding to cysteine-481 near the ATP binding domain of BTK. These small molecules irreversibly inhibited BTK by using a Michael acceptor for binding to the target cysteine. In April 2006, Pharmacyclics acquired Celera’s small molecule BTK inhibitor discovery program, which included a compound, PCI-32765 (known as compound 13 in the Pan et al paper) that was subsequently chosen for further preclinical development based on the discovery of anti-lymphoma properties in vivo . Since 2006, Pharmacyclics’ scientists have advanced the molecule into clinical trials and identified specific clinical indications for the drug.    It also has potential effects against autoimmune arthritis.
It has given good results in two phase II clinical trials.
In preclinical studies on chronic lymphocytic leukemia (CLL) cells, ibrutinib has been reported to promote apoptosis, inhibit proliferation, and also prevent CLL cells from responding to survival stimuli provided by the microenvironment. In this study, treatment of activated CLL cells with ibrutinib resulted in inhibition of Btk tyrosine phosphorylation and also effectively abrogated downstream survival pathways activated by this kinase including ERK1/2, PI3K, and NF-κB. Additionally, ibrutinib inhibited proliferation of CLL cells in vitro, effectively blocking survival signals provided externally to CLL cells from the microenvironment including soluble factors (CD40L, BAFF, IL-6, IL-4, and TNF-α), fibronectin engagement and stromal cell contact.
In early clinical studies, the activity of ibrutinib has been described to include a rapid reduction in lymphadenopathy accompanied by a transient lymphocytosis, suggesting that the drug might have direct effects on cell homing or migration to factors in tissue microenvironments.
Ibrutinib has been reported to reduce CLL cell chemotaxis towards the chemokines CXCL12 and CXCL13, and inhibit cellular adhesion following stimulation at the B cell receptor. Together, these data are consistent with a mechanistic model whereby ibrutinib blocks BCR signaling, which drives cells into apoptosis and/or disrupts cell migration and adherence to protective tumor microenvironments.
- ^ Statement on a Nonproprietary Name Adopted by the USAN Council
- ^ Pan, Z; Scheerens, H; Li, SJ; Schultz, BE; Sprengeler, PA; Burrill, LC; Mendonca, RV; Sweeney, MD et al. (2007). “Discovery of selective irreversible inhibitors for Bruton’s tyrosine kinase”. ChemMedChem 2 (1): 58–61. doi:10.1002/cmdc.200600221. PMID 17154430.
- ^ Celera Genomics Announces Sale of Therapeutic Programs to Pharmacyclics
- ^ United States patent 7514444
- ^ Honigberg, LA; Smith, AM; Sirisawad, M; Verner, E; Loury, D; Chang, B; Li, S; Pan, Z; Thamm, DH; Miller, RA; Buggy (2010). “The Bruton tyrosine kinase inhibitor PCI-32765 blocks B-cell activation and is efficacious in models of autoimmune disease and B-cell malignancy”. Proceedings of the National Academy of Sciences of the United States of America 107 (29): 13075–80. doi:10.1073/pnas.1004594107. PMID 20615965. Unknown parameter
- ^ Janssen Biotech, Inc. Announces Collaborative Development and Worldwide License Agreement for Investigational Anti-Cancer Drug, PCI-32765
- ^ Clinical trials involve PCI-32765
- ^ Clinical trials involve ibrutinib
- ^ Chang, BY; Huang, MM; Francesco, M; Chen, J; Sokolove, J; Magadala, P; Robinson, WH; Buggy, JJ (2011). “The Bruton tyrosine kinase inhibitor PCI-32765 ameliorates autoimmune arthritis by inhibition of multiple effector cells”. Arthritis Research & Therapy 13 (4): R115. doi:10.1186/ar3400. PMID 21752263.
- ^ Good News Continues for Ibrutinib in CLL. 8 Dec 2012
- ^ Herman SE, Gordon AL, Hertlein E, Ramanunni A, Zhang X, Jaglowski S, Flynn J, Jones J, Blum KA, Buggy J.J., Hamdy A, Johnson AJ, Byrd JC. (2011) Bruton’s tyrosine kinase represents a promising therapeutic target for treatment of chronic lymphocytic leukemia and is effectively targeted by PCI-32765. Blood 117: 6287-6296
- ^ The Bruton’s tyrosine kinase (BTK) inhibitor PCI-32765 (P) in treatment-naive (TN) chronic lymphocytic leukemia (CLL) patients (pts): Interim results of a phase Ib/II study.J Clin Oncol 30, 2012 (suppl; abstr 6507)
- ^ Ponader S, Chen SS, Buggy JJ, Balakrishnan K, Gandhi V, Wierda WG, Keating MJ, O’Brien S, Chiorazzi N, Burger JA. (2012) The Bruton tyrosine kinase inhibitor PCI-32765 thwarts chronic lymphocytic leukemia cell survival and tissue homing in vitro and in vivo. Blood 119: 1182-1189.
- ^ de Rooij MF, Kuil A, Geest CR, Eldering E, Chang BY, Buggy JJ, Pals ST, Spaargaren M. (2012) The clinically active BTK inhibitor PCI-32765 targets B-cell receptor (BCR)- and chemokine-controlled adhesion and migration in chronic lymphocytic leukemia. Blood 119: 2590-2594.