Ibrutinib




Concerns over section 11: "Optimisation of medicines use"Pharmacology

Pharmacological effect - antitumor.

Pharmacodynamics


Mechanism of action. Ibrutinib Dosage is a powerful low-molecular weight inhibitor of Bruton's tyrosine kinase (TCB). Ibrutinib forms a covalent bond with the cysteine residue (Cys 481) in the active centre of the TKB, resulting in persistent inhibition of enzymatic activity. TKB, a member of the Tes family of kinases, acts as an important signal molecule in metabolic pathways associated with the signal activity of antigenic B-cell receptors (BCR) and cytokine receptors. The BCR signaling pathway is involved in the pathogenesis of a number of B cell malignancies, including mantle cell lymphoma, diffuse coarse cell B cell lymphoma, follicular lymphoma, and B cell chronic lymphocytic leukemia. The key role of TKB in the signaling activity of B-cell surface receptors leads to activation of signaling pathways necessary for B-cell migration, their chemotaxis and adhesion. According to preclinical studies, ibrutinib inhibits the proliferation and survival of malignant B cells in vivo, as well as cell migration and their adhesion to substrates in vitro.


RxList.com


In patients with recurrent B-cell lymphoma >90% of active TBK center employment in peripheral blood mononuclear cells is observed for the period up to 24 hours after intake of ibrutinib in doses of ≥2.5 mg/kg/day (≥175 mg/day at an average weight of 70 kg).


Lymphocytosis. At the beginning of therapy, most patients (75%) with chronic lymphocytic leukaemia who received ibrutinib had a reversible increase in the number of lymphocytes (i.e. 50% or more of the baseline with absolute values above 5000/µL), often accompanied by a decrease in lymphadenopathy. This effect was also present in some patients (35%) with recurrent or refractory lymphoma from mantle cells receiving ibrutinib. The lymphocytosis observed is a reflection of the pharmacodynamic effect, and should not be considered a progression of the disease in the absence of other clinical manifestations. In both diseases, lymphocytosis usually developed during the first few weeks of treatment with ibrutinib (median 1.1 weeks) and was usually resolved at median 8 and 18.7 weeks in patients with recurrent or refractory mantle cell lymphoma and chronic lymphocytic leukemia, respectively.


A significant increase in the number of circulating lymphocytes (i.e. over 400000/µL) was observed in some patients.


RxList.com


Lymphocytosis Ibrutinib. In a study of patients with mantle cell lymphoma, a temporary increase in lymphocyte levels (i.e. ≥50% increase compared to baseline and absolute values above 5000/µL) after inducing ibrutinib was observed in 33% of patients. Lymphocytosis developed during the first few weeks of ibrutinib therapy and was resolved with a median of 8 weeks.


In a study of patients with chronic lymphocytic leukemia, an increase in lymphocyte levels (i.e., ≥50% increase over baseline and absolute values above 5000/µL) was observed in 77% of patients after ibrutinib. Lymphocytosis developed during the first month of ibrutiniba therapy and was resolved with a median of 23 weeks.


Pharmacokinetics .

                       

Suction. Ibrutinib is quickly absorbed after oral intake with a median Tmach 1-2 hours. Patients with various B-cell malignancies have no significant differences in the pharmacokinetics of ibrutinib Contraindications. The concentration of ibrutinib in plasma is proportionally increased with increasing dose up to 840 mg. The equilibrium AUC value in patients at 560 mg dose is (953±705) ng/h/ml (mean ± standard deviation). A meal with food leads to an increase in ibrutinib concentration by about 2 times compared to an on an empty stomach meal (without meals from the previous evening).



AUTOMATIC GENERIC SUBSTITUTION

Automatic generic substitution (AGS) is the term for a scheme proposed by the Department of Health (DH) in 2009. AGS would have allowed pharmacists to dispense a generic version of a medication (a version with the same active ingredient), even if the doctor had written the prescription for a specific brand.


The Department of Health says no to AGS

After a consultation that resulted in written responses from 423 organisations and individuals, the DH announced, on 14 October 2010, that it had stopped plans to introduce AGS by pharmacists. The DH decided that concerns over patient safety were sufficiently grounded in fact and that it was therefore not appropriate to implement AGS.1

 

Taking Action Works!

The DH decided not to proceed with AGS as it reviewed the responses to the consultation and agreed that AGS was too great a risk to patients.

The correct use of medicines is important for achieving this goal, and the role of pharmacists is fully acknowledged in helping to achieve this. However, it is important that the relevant MHRA legislation is worded accurately to ensure that generic substitution or even therapeutic substitution by pharmacists is not inadvertently embedded in medicines legislation.

Thank you to those that acted last time - we are delighted that the DH listened to us and acted on our concerns.

Hexomedine

Parasinus

Cancer

Losing the right medication for the right patient

Norgine position paper

Norgine discussion. There is no Substitute

Outcome of DoH consultation on generic substitution

14th October 2010

Contacts

Julie Hornby Winfield
Norgine
[email protected]
+44 (0)1895 826642

Jennifer Garratt
Burson-Marsteller
[email protected]
+44 (0) 207 300 6240

References

  • The proposals to implement 'generic substitution' in primary care, further to the Pharmaceutical Price Regulation Scheme (PPRS) 2009. Response to the consultation.
  • MHRA Consolidation and review of UK medicines legislation. 25 October 2011. http://www.mhra.gov.uk/Publications/Consultations/Medicinesconsultations/MLXs/CON132054 [Last accessed December 2011]

This website is sponsored by Norgine Pharmaceuticals Ltd


MEGS/2739/DEC11

Norgine Automatic Generic Substitution