Drug monitoring in systemic lupus erythematosus

Therapeutic Hydroxychloroquine Blood Levels Are Associated With Fewer Hospitalizations and Possible Reduction of Health Disparities in Lupus

OBJECTIVE

Nonadherence to receiving hydroxychloroquine (HCQ) is associated with a three-fold higher risk of lupus-related hospitalization. Monitoring HCQ blood levels could improve adherence to receiving HCQ and efficacy. Yet, HCQ level monitoring is not routinely done partially due to cost and coverage concerns. To establish HCQ level monitoring cost-effectiveness, we reported the following: (1) risk of acute care by HCQ blood levels, and (2) cost of HCQ monitoring versus acute care visits.

METHODS

HCQ blood levels were measured during routine lupus visits. HCQ levels were categorized as follows: (1) subtherapeutic (<750 ng/mL), (2) therapeutic (750-1,200 ng/mL), or (3) supratherapeutic (>1,200 ng/mL). All lupus-related acute care visits (emergency room visits/hospitalizations) after the index clinic visit until next follow-up were abstracted. In our primary analysis, we examined associations between HCQ levels and time to first acute care visit in all patients and subgroups with higher rates of acute care.

RESULTS

A total of 39 lupus-related acute care visits were observed in 181 patients. Therapeutic HCQ blood levels were associated with 66% lower rates of acute care. In our cohort, two groups, Black or Hispanic patients and those with public insurance, faced three to four times higher rates of acute care. Levels within 750 to 1,200 ng/mL were associated with 95% lower rates of acute care use in subgroups with higher acute care use.

CONCLUSION

HCQ blood levels within 750 to 1,200 ng/mL are associated with lower rates of acute care in all patients with lupus, including groups with higher rates of acute care. Future clinical trials should establish the causal association between HCQ level monitoring and acute care in patients with lupus.

Mendelian randomization analysis reveals a protective association between genetically predicted systemic lupus erythematosus and renal cell carcinoma

Observational studies have suggested that there may be a connection between systemic lupus erythematosus (SLE) and a higher likelihood of developing urological cancers, although the exact cause-effect relationship is still unclear. This study therefore investigated the causal relationship between SLE and urological cancers using the Mendelian randomization (MR) approach. Our primary MR analysis involved using the inverse variance weighted method, which employed an inverse-variance-weighted approach, to examine the causal relationship between SLE and urological conditions. In addition, we performed various sensitivity analyses, such as MR-Egger regression, tests for heterogeneity, and leave-one-out sensitivity tests, to assess the reliability of our results. The findings from our analysis using Two-Sample MR showed that genetically predicted SLE was linked to a reduced likelihood of developing renal cell carcinoma (RCC) (odds ratio = 0.9996, 95% confidence interval = 0.9993-0.9999, P value = .0159). These results suggest a possible protective impact of SLE against RCC. Nevertheless, no substantial correlation was detected between SLE and the likelihood of developing bladder cancer or prostate cancer. Collectively, these findings offer significant fresh perspectives on the possible correlation between SLE and genitourinary malignancies, specifically RCC, which will provide ideas and basis for the treatment of RCC.

Therapeutic Drug Monitoring in Patients with Systemic Lupus Erythematosus: Utility and Gaps

Despite advances in the treatment of patients with systemic lupus erythematous (SLE), outcomes have remained suboptimal. Persistent disease activity, patient comorbidities and drug toxicities contribute to the accrual of progressive irreversible damage and high rates of morbidity and mortality. Currently, similar drug doses and regimens are promulgated in the treatment guidelines for all SLE patients, despite the vast differences in patient and environmental factors that affect the drugs' metabolism and blood concentrations. This causes a disconnect between drug dosing and drug blood concentrations, which can then result in unpredictability in drug toxicities and therapeutic effects. In this review, we discuss commonly used oral immunosuppressive medications in SLE, their pharmacogenomics, and factors affecting their metabolism and blood concentrations. Further, we highlight the role of therapeutic drug monitoring in SLE, which is the first accessible step to individualising therapy.

When should targeted therapies be used in the treatment of lupus nephritis: Early in the disease course or in refractory patients?

Although the prognosis of lupus nephritis (LN) has improved over the last few decades, 5-20% of patients still progress to kidney failure. Hence, there is an unmet need to improve the management of LN. Two novel drugs, belimumab and voclosporin, have been recently approved for LN and obinutuzumab is in the late stage of development. In randomised controlled trials (RCTs), all these drugs, added to the standard-of-care, were more effective than standard-of-care alone in achieving renal response. Now the question is: should these new drugs be used early in the disease course or just in refractory patients? The main reasons supporting the early use are based on the RCTs that demonstrated benefits when combinatory regimen was initiated early in incident and relapsing patients leading to a higher proportion of patients to achieve renal response, hence reducing nephron loss and the risk of kidney failure. The main reasons supporting the use of the combinatory regimens primarily in relapsing/refractory patients acknowledge that many patients responded well even without add-on medications, allowing a more economic use of innovative and costly drugs. However, good predictors of renal response to standard-of-care are lacking and, thus, the decision of adding new treatments early or just in refractory or relapsing patients has to consider drug access, risks of over or undertreatment, and preservation of kidney function in high-risk individuals.