a journey through immunosuppressive effect of CNI, How they work, pharmacokinetic polymorphism side effect, avoidance and minimization

1. Calcineurin inhibitors
friend or foe
By
Dr. Salwa Mahmoud Elwasif, MD

2. What is calcineurin?
• Immunophilin
• Enzyme
• Cytokine
• chemokine
• Extracellular
• Intracellular
• Protein
(amino acid)
• Lipid (fatty
acid)
• CHO

3. What is calcineurin?
• Immunophilin
• Enzyme
• Cytokine
• chemokine
• Extracellular
• Intracellular
• Protein
(amino acid)
• Lipid (fatty
acid)
• CHO

4. What is calcineurin?
• It is a calcium and calmodulin dependent
serine/threonine protein phosphatase.
• also known as protein phosphatase 3, and
calcium-dependent serine-threonine
phosphatase.

5. Role of Calcineurin in immunity
• It activates nuclear factor of activated T cell cytoplasmic
(NFATc), a transcription factor, by dephosphorylating it.
The activated NFATc is then translocated into the
nucleus, where it upregulates the expression
of interleukin 2 (IL-2), which, in turn, stimulates the
growth and differentiation of the T cell response.

6. Ca
CaN
NFATc
IL2

7. • When an antigen presenting cell interacts with a
Tcell receptor , there is an increase in the
cytoplasmic level of calcium, which activates
calcineurin by binding a regulatory subunit and
activating calmodulin binding.
• Calcineurin induces transcription factors (NFATc)
that are important in the transcription of IL-2
genes.
• IL-2 activates T-helper lymphocytes and induces
the production of other cytokines.

8. Which signal?

11. • Cyclosporine and tacrolimus are chemically distinct
molecules that bind to the intracellular immunophilins
cyclophilin and FKBP-12, respectively.
• When bound, both molecules inhibit the phosphatase
action of calcineurin
• Decreased secretion of IL-2 prevents proliferation of the
inflammatory response via T cells.
• The attenuated inflammatory response greatly reduces the
overall function of the immune system.

12. History
• CNI were used in solid organ transplantation

14. Cyclosporine (CsA) (Cyclic peptide
from Soil Fungus (1971)
• 1983: Sandimmune Used in renal transplantation
• 1995: Neoral (microemulsion)

15. • Sandimmune, or cyclosporine, is an immediate-
release capsule.
• Neoral, or cyclosporine (modified), is a
microemulsion formulation that minimizes
intraindividual absorption variability.
Sandimmune and Neoral are not bioequivalent and
should not be substituted without appropriate
dose adjustments.

18. Other formulations
• cyclosporine injectable products
• cyclosporine oral solutions
• cyclosporine eye drops

19. Tacrolimus
• first discovered in 1987 from the fermentation
broth of a Japanese soil sample that contained
the bacterium Streptomyces tsukubaensis

20. Other forms of tac.
• Long acting tacrolimus (advagraf)
• a topical tacrolimus ointment
• tacrolimus injectable product.

21. Effects of Genetic Polymorphisms on the
Pharmacokinetics of Calcineurin Inhibitors
• Cyclosporine and tacrolimus are highly lipophilic
molecules yet display dissimilar absorption
kinetics.
• Cyclosporine depends greatly on gastrointestinal
function and bile secretion for adequate
absorption.
• Sandimmune absorption kinetics display high
interindividual and intraindividual variability. Peak
blood concentrations occur within 2-6 hours.

22. • Neoral provides patients with rapid and
consistent absorption, where peak blood
concentrations occur within 1.5-2 hours.
• The elimination half-life is 19 and 8.4 hours for
Sandimmune and Neoral, respectively.

23. • Tacrolimus is consistently absorbed and
eliminated, with a half-life of 8.7 hours.
• Pharmacokinetic variability of approximately 20-
30% among patients is noted in product labeling.

24. • Reaching therapeutic levels with cyclosporine as
early as three days postoperatively has been
shown to decrease the rate of acute organ
rejection in kidney transplant recipients.
• Suggested starting dosages are 9 mg/kg/day for
Neoral, 10-14 mg/kg/day for Sandimmune, and
0.2 mg/kg/day for tacrolimus.

26. • variable expression of functional CYP3A4 enzymes,
CYP3A5 enzymes, and PGP efflux pumps. The
differences in expression level may be the result of
single-nucleotide polymorphism (SNPs) found on
the genes encoding CYP3A4, CYP3A5, and PGP.
• One such polymorphism has been identified in the
gene encoding for the CYP3A4 enzyme, labeled
as CYP3A4*1B, and is found in 46-66% of people
from African descent, 4% of Caucasians, and 0% of
Asians.

28. • The bioavailability and metabolism of cyclosporine and
tacrolimus are primarily controlled by efflux pumps and
members of the cytochrome P-450 (CYP) isoenzyme
system found in the liver and gastro-intestinal tract.
• The main efflux pump involved in transporting
cyclosporine and tacrolimus is P-glycoprotein (PGP),
which is encoded by the multidrug resistance-1
(MDR1), also known as the ABCB1, gene.

29. • PGP is a transmembrane transporter capable of
transporting numerous endogenous substances
from the cytoplasm to the exterior of the cell.
• In the intestines, PGP limits oral bioavailability of
drugs by expelling them from the interior of
enterocytes into the gut lumen

30. • Two distinct polymorphisms have also been
found in the gene encoding for CYP3A5. The
first, CYP3A5*3, is an SNP in intron 3 that creates
a premature stop codon, resulting in protein
truncation and inactivation of the CYP3A5
enzyme.
• The second polymorphism, CYP3A5*6, is located
in intron 6 and also creates a premature stop
codon that decreases transcription of CYP3A5
mRNA.

31. • The SNP presence in the promoter region
increases CYP3A4 transcription in vitro. In vivo
studies have failed to corroborate these findings,
showing no change in the metabolism of known
CYP3A4 substrates when the CYP3A4*1B SNP is
present.
• It remains unclear whether the CYP3A4*1B SNP
affects the metabolism of CYP3A4 substrates, but
the possibility is being examined to determine if
the SNP’s presence has any predictive value for
drug metabolism.

32. Personalized medicine

34. Side effect
• They are not bomboni

35. Cyclosporine Tacrolimus

36. The renal tubules
• tubular dysfunction includes hyperkalemia due to
aldosterone resistance and a decrease in the
Na+/K+ ATPase pump ,
• hypomagnesemia due to a decreased expression of
paracellin 1 in the thick ascending loop of Henle
• hyperuricemia due to a decrease in uric acid
tubular secretion .
• A reduced expression of the Na+/K+-
2Cl− transporter has also been described and may
result in nephrocalcinosis, polyuria, and
juxtaglomerular hyperplasia

37. Chronic nephrotoxicity
• Arterial hyalinosis is frequently irreversible owing to
prolonged vasoconstriction or the regulation of NFAT and
smooth muscle .
• Tubulointerstitial injuries classically described as stripped
fibrosis and tubular atrophy are multifactorial in origin,
resulting from an increase in free radicals , an upregulation
of TGF-β leading to epithelial to mesenchymal transition ,
or an activation of the renin-angiotensin-aldosterone
system with an increase in aldosterone.

38. Chronic nephrotoxicity
• Other tubular lesions are seen and include isometric
tubular vacuolization and inclusion bodies due to an
increase in lysozymes and giant mitochondria .
• The main glomerular lesions include global
glomerulosclerosis due to secondary ischemia or focal
segmental glomerulosclerosis secondary to
hyperfiltration injury.

39. • Aldosterone seems to be playing a central role
in CNI toxicity because aldosterone
antagonists may prevent the functional or
structural renal lesions

43. Monitoring
• In spite of serious side effect, it is mandatory
to use.

44. • Trough level (Pre dose)
• C2

45. • Proposed alternatives include the area under
the concentration-time curve (AUC) at 4 hours
(AUC0–4 hr) and 12 hours (AUC0–12 hr) and blood
drug concentrations at 2, 3, or 4 hours after
administration.
• Therapeutic cyclosporine concentrations differ
with the measurement technique, institution,
and protocol.

46. • The therapeutic trough whole blood and serum
concentrations of cyclosporine are 375-400 and
150-250 ng/mL, respectively, when measured
with radioimmunoassay
• 100-300 and 75-150 ng/mL, respectively, when
measured with high-performance liquid
chromatography.

47. • Therapeutic trough whole blood concentrations
of tacrolimus are 15-20 (initial concentration), 10-
15 (at one month), and 5-12 ng/mL (at three
months posttransplantation) (equivalent to free
plasma concentrations of 0.5-2 ng/mL).
• Published serum concentrations for the
calcineurin inhibitors are only a guide, and
individual therapy should be tailored specifically
to each patient based on risk factors and the
clinical situation.

48. Mansoura unc
• Immunoassey
• Whole blood

49. Journey

54. SYMPHONY trial
• The randomized 1645 renal transplant recipients to
one of four immunosuppressive regimens.
• normal-dose cyclosporine, mycophenolate mofetil
(MMF) and steroids;
• the second, following induction with daclizumab,
received low-dose cyclosporine (trough levels
between 50 and 100 ng/mL), MMF and steroids;
• the third, again following daclizumab induction,
received low-dose tacrolimus (trough levels
between 3 and 7 ng/mL), MMF and steroids;
• Tac (4 to 8 mg/mL), MMF and steroids, again
following induction with daclizumab.

58. Kdigo guideline

59. K digo, monitoring

61. The question now……

62. Thank you