Voclosporin Food Effect and Single Oral Ascending Dose Pharmacokinetic and Pharmacodynamic Studies in Healthy Human Subjects

Safety and Efficacy of Long-Term Voclosporin Treatment for Lupus Nephritis in the Phase 3 AURORA 2 Clinical Trial

OBJECTIVE

AURORA 2 evaluated the long-term safety, tolerability, and efficacy of voclosporin compared to placebo in patients with lupus nephritis (LN) receiving an additional two years of treatment following completion of the one-year AURORA 1 study.

METHODS

Enrolled patients continued their double-blinded treatment of voclosporin or placebo randomly assigned in AURORA 1, in combination with mycophenolate mofetil and low-dose glucocorticoids. The primary objective was safety assessed with adverse events (AEs) and biochemical and hematological assessments. Efficacy was measured by renal response.

RESULTS

A total of 216 patients enrolled in AURORA 2. Treatment was well tolerated with 86.1% completing the study and no unexpected safety signals. AEs occurred in 86% and 80% of patients in the voclosporin and control groups, respectively, with an AE profile similar to that seen in AURORA 1, albeit with reduced frequency. Investigator reported AEs of both glomerular filtration rate (GFR) decrease and hypertension occurred more frequently in the voclosporin than the control group (10.3% vs 5.0%, and 8.6% vs 7.0%, respectively). Mean corrected estimated GFR (eGFR) was within the normal range and stable in both treatment groups. eGFR slope over the two-year period was -0.2 mL/min/1.73 m2 (95% confidence interval [CI] -3.0 to 2.7) in the voclosporin group and -5.4 mL/min/1.73 m2 (95% CI -8.4 to -2.3) in the control group. Improved proteinuria persisted across three years of treatment, leading to more frequent complete renal responses in patients treated with voclosporin (50.9% vs 39.0%; odds ratio 1.74; 95% CI 1.00-3.03).

CONCLUSION

Data demonstrate the safety and efficacy of long-term voclosporin treatment over three years of follow-up in patients with LN.

Clinical Pharmacokinetics and Pharmacodynamics of Voclosporin

Voclosporin is an approved option for the long-term treatment of lupus nephritis. We aimed to provide a narrative review of the pharmacokinetics and pharmacodynamics of voclosporin. In addition, we derived values for pharmacokinetic and pharmacodynamic parameters by graphical analysis of published diagrams. Compared with cyclosporin, low-dose voclosporin is associated with a lower nephrotoxicity risk and, compared to tacrolimus, with a lower diabetes risk. After repetitive dosing of 23.7 mg twice daily and at target trough concentrations of 10-20 ng/mL, the dominant or effect-indicative half-life is estimated at 7 hours. Compared with the pharmacodynamics of cyclosporin, the potency of voclosporin is stronger, with a lower concentration CE₅₀ of 50 ng/mL already producing the half-maximum immunosuppressive effect. The Hill coefficient can be predicted to be low at H = 1.3, indicating a concentration-dependent effect on the immune system. The corresponding effect bisection time of 10 hours allows for dosing every 12 hours. Accordingly, the trough concentration will be above the threshold concentration that produces 5% of the maximum effect of 5.2 ng/mL for immunosuppression but below both the predicted threshold of 30 ng/mL for nephrotoxicity and the predicted threshold of 40 ng/mL for new-onset diabetes. The pharmacokinetic and pharmacodynamic properties suggest the use of low-dose voclosporin combined with mycophenolate and low-dose glucocorticoids for immunosuppressive maintenance therapy.

Voclosporin: a novel calcineurin inhibitor for the treatment of lupus nephritis

INTRODUCTION

Lupus nephritis (LN) is a severe manifestation of systemic lupus erythematosus. Standard-of-care immunosuppressive therapies achieve poor complete renal response (CRR) rates, with considerable toxicity. This article reviews voclosporin, a novel oral calcineurin inhibitor (CNI) approved for treatment of adults with active LN by the US Food and Drug Administration (the FDA) in January 2021.

AREAS COVERED

: This review summarizes the chemical properties, pharmacokinetics, and pharmacodynamics of voclosporin, and its efficacy and safety in LN, based on literature review covering PubMed searches, manufacturers' websites and documents produced by the FDA.

EXPERT OPINION

: Voclosporin is a CNI with a consistent pharmacokinetic-pharmacodynamic relationship resulting from enhanced calcineurin binding and reduced drug and metabolite load. This profile permits therapeutic efficacy in LN at a dose associated with relatively low calcineurin inhibition, and therefore a potentially improved safety profile. Pivotal trials demonstrated a significant benefit of adding voclosporin to standard therapy, with rapid reduction in proteinuria, and a clinically meaningful and significantly higher CRR rate at 1 year. At approved doses for LN, potential advantages of voclosporin versus historical experience with CNIs include lack of need for therapeutic drug monitoring, benign metabolic, lipid and electrolyte profile, and no impact on mycophenolate mofetil levels.

Old and New Calcineurin Inhibitors in Lupus Nephritis

Calcineurin inhibitors (CNIs) are drugs that inhibit calcineurin, a key phosphatase that dephosphorylates a transcription factor called the nuclear factor of activated T cells (NFAT), allowing its translocation into the nucleus of quiescent T cells. In the nucleus, NFAT activates interleukin 2, which stimulates the proliferation and differentiation of T-cells. CNIs can also stabilize the actin cytoskeleton of podocytes reducing proteinuria. Thanks to these characteristics, CNIs have been often used in the treatment of autoimmune diseases. However, the therapeutic index of CNIs is narrow, and their interactions with other drugs can increase toxicity or reduce efficacy. In lupus nephritis, cyclosporine and tacrolimus have been used both in induction and maintenance therapies. Observational studies and randomized controlled trials showed that both cyclosporine and tacrolimus can increase efficacy. Tolerance is satisfactory if low doses are used and the patient is carefully monitored. More recently, a new CNI, called voclosporin (VCS), has been approved by the Food and Drug Administration for use in lupus nephritis. VCS offers potential advantages over other CNIs. In two large multiethnic trials, VCS was not associated with adverse renal and metabolic events and obtained positive results despite a novel and rapid corticosteroid tapering regime.

Voclosporin: a novel calcineurin inhibitor for the management of lupus nephritis

INTRODUCTION

Kidney survival rates in lupus nephritis (LN) remain suboptimal, with 10-20% of patients progressing to end-stage kidney disease by 10-20 years. Recently, the landscape of LN management has changed with the advent of new molecules that have demonstrated safety and efficacy in clinical trials.

AREAS COVERED

In this review, we approach the current state of LN management, the unmet therapeutic needs, and deep dive into voclosporin, a novel calcineurin inhibitor (CNI) that has demonstrated improved efficacy when added to a mycophenolate mofetil (MMF) and glucocorticoid regimen, without an increase in adverse events. We focus on the characteristics of this new CNI and the studies that led to its approval by the US FDA.

EXPERT OPINION

Voclosporin adds to therapeutic options for LN. This drug offers potential advantages over other CNIs. The addition of voclosporin to a standard-of-care regimen of MMF/glucocorticoids demonstrated higher and faster response rates. As other regimens, a combination of CNI, MMF, and glucocorticoids must be individualized and is not appropriate for all patients. Some questions remain to be answered for this regimen, such as the length of treatment, the tapering schedule, and its long-term safety and efficacy for preserving kidney function.

Voclosporin: First Approval

Voclosporin (Lupkynis^™) is an oral calcineurin inhibitor immunosuppressant that is being developed by Aurinia Pharmaceuticals. In January 2021, based on positive results from the pivotal phases II and III trials, oral voclosporin received its first approval in the USA for use in combination with a background immunosuppressive therapy regimen for adults with active lupus nephritis. Voclosporin is also being explored for the novel coronavirus disease 2019 (COVID-19) in kidney transplant recipients. This article summarizes the milestones in the development of voclosporin leading to this first approval for lupus nephritis.

Pharmacokinetic Disposition Difference Between Cyclosporine and Voclosporin Drives Their Distinct Efficacy and Safety Profiles in Clinical Studies

Background

Voclosporin, a more potent derivative of cyclosporine, has been studied extensively in patients with immunologic disorders such as psoriasis, organ transplantation, uvetitis and lupus nephritis. Although better tolerated and safer than cyclosporine, voclosporin is inferior to cyclosporine in treating psoriasis, non-inferior to tacrolimus in organ transplantation and efficacious in treating lupus nephritis.

Methods

The pharmacokinetic dispositions of voclosporin and cyclosporine in central and peripheral compartments were analyzed and correlated with their distinct clinical efficacy and safety profiles.

Results

Both drugs demonstrated non-linear pharmacokinetics with increasing doses, more prominently at lower doses of voclosporin than at 10-fold higher doses of cyclosporine. Repeated lower dosing of voclosporin produced preferential calcineurin inhibition in and near blood circulation, leading to relatively lower cardiovascular and renal adverse effects but inferior efficacy for psoriasis compared to cyclosporine. With 10-fold higher plasma levels and deeper tissue penetration, cyclosporine has more prevalent renal and cardiac toxicities but superior efficacy to treat psoriasis.

Conclusion

Although the two drugs are similar in structure and mechanism of action, the high potency and low dose compounded by the non-linear disposition of voclosporin resulted in more systemic versus local calcineurin inhibition than with cyclosporine. The dispositional difference between voclosporin and cyclosporine accounted for the puzzling efficacy and safety observations in different patients and was the basis for their optimal and differential use in treating diverse immunologic disorders.

Population PKPD of voclosporin in renal allograft patients

The aims of this population-pharmacokinetic/pharmacodynamic (POP-PKPD) analysis of voclosporin in renal allograft patients were to build a POP-PKPD model for voclosporin and calcineurin activity (CNa) and identify clinically relevant covariates that could assist dosing of the drug. POP-PKPD modeling was performed using a stochastic approximation of the standard expectation maximization (SAEM) algorithm for nonlinear mixed-effects as implemented in Monolix™ 3.2. Voclosporin whole blood concentrations were obtained from de novo renal allograft patients and assayed using a validated LC/MS/MS assay. CNa was measured using a (32)P-radiolabeled assay. A two-compartment model with simultaneous sigmoid inhibitory Emax model was used to describe the PKPD relationship between voclosporin concentration and CNa. The POP-PKPD model was then utilized to simulate an optimal initial dosing strategy. Eighty-seven patients were included in the POP-PKPD study. Population mean estimates (relative standard error, rse) for oral clearance (CL/F) and first compartment volume of distribution (V1), were 717 mL min(-1) (35%) and 2010 mL (17%), respectively. Maximum CNa Inhibition (Imax), effective concentration (C50), and baseline immunosuppression (S0) were 0.87 pmol/min/mg (8.0%), 123 ng/mL (10%), and 1.15 pmol/min/mg (4.0%), respectively. Covariate analyses demonstrated that age and body surface area significantly influenced CL/F: CLi=717(Agei/48.8)-0.57(BSAi/1.99)1.1, while serum triglycerides significantly altered S0: S0i=1.15(TRIGi/1.97)0.15.