Long-term post-marketing surveillance of mizoribine for the treatment of lupus nephritis: Safety and efficacy during a 3-year follow-up

Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism

Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.

Post-marketing surveillance study of the long-term use of mizoribine for the treatment of lupus nephritis: 2-Year results

OBJECTIVES

To understand the status of mizoribine use in patients with lupus nephritis (LN) and to collect safety- and efficacy-related data on 2-year treatment with mizoribine.

METHODS

A continuous survey was conducted between March 2010 and July 2015.

RESULTS

The analysis set included 559 patients (mean age 39.5 years, females 82.6%, mean duration of systemic lupus erythematosus (SLE) 8.4 years, mean duration of LN 5.9 years). Renal function was satisfactory for 6 months, but worsened from 12 months, with significant worsening at 24 months. By the ACR 2006 remission criteria (eGFR >60), at 24 months, 26.5% of patients achieved complete remission, and 63.3% achieved complete or partial remission. The urine protein to creatinine ratio decreased significantly. The SLE Disease Activity Index 2000 score decreased significantly at 12 and 24 months. Overall, 98 (17.5%) patients experienced 124 adverse drug reactions (ADRs); 3.6% experienced serious ADRs. Mizoribine was used with a steroid in 99.3% and an immunosuppressant in 51.2%; tacrolimus was used in 43.8%. The oral steroid dosage decreased from baseline to 24 months. The incidence of ADRs was not significantly different with concomitant tacrolimus use.

CONCLUSIONS

The results suggest that long-term mizoribine is safe and effective, even when used with tacrolimus.