Lupus & antiphospholipid syndrome
The influence of CYP3A5 genotype on tacrolimus pharmacokinetics in patients with SLE
Authors' conclusion
CYP3A5 non-expresser genotype increases TAC concentrations in SLE. Initial TAC dosing without considering CYP3A5 status leads to a significant therapeutic lag in expressers.
Study context
- Population
- Patients with SLE receiving tacrolimus (TAC), Kyoto Lupus Cohort78 newly initiating TAC
- Participants
- 114 patients
- Exposure
- CYP3A5 non-expressers vs expressers
- Outcome
- Time-averaged TAC trough concentration-to-dose (C/D) ratio by CYP3A5 genotype
Methodological detailssingle cohort (Kyoto Lupus Cohort)
- Single cohort (Kyoto Lupus Cohort)
Main finding
As reported in the abstract
Time-averaged TAC C/D ratio
- 1.6-fold higher in non-expressers (*3/*3) vs expressers
Observational data: associations, not effects.
Further findings
TAC dose · 1 month
P = 0.03
TAC blood concentration · 1 month
P = 0.04
- TAC blood concentration: concentrations paradoxically lower in expressers despite higher doses
TAC concentrations and clinical outcomes after dose adjustment · 12 months
- Comparable concentrations in both genotypes
- ∼4.8 ng/ml
- Clinical improvements (reduced SLEDAI-2K and prednisolone sparing)
Decline of renal function · 12 months
- Predominantly driven by age and baseline renal function rather than CYP3A5 genotype
Original publication
The influence of CYP3A5 genotype on tacrolimus pharmacokinetics in patients with SLE. Rheumatology (Oxford). Published 9 April 2026. doi:10.
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