Brief Report: Tyrosine Kinase Inhibitors for Lung Cancers That Inhibit MATE-1 Can Lead to "False" Decreases in Renal Function.

INTRODUCTION: Select tyrosine kinase inhibitors (TKIs) used to treat oncogene-driven lung cancers also inhibit MATE-1. When MATE-1 is blocked, creatinine is retained in the serum. Elevated creatinine levels raise the specter of drug-induced intrarenal insufficiency despite the lack of true renal injury. We conducted a systematic analysis of MATE-1 inhibitor (MATEi)-treated patients to comprehensively characterize this phenomenon. METHODS: Patients with oncogene-driven lung cancer treated with a wide variety of MATEi TKIs (brigatinib, cabozantinib, capmatinib, crizotinib, entrectinib, lorlatinib, pralsetinib, selpercatinib, and tepotinib) were eligible for an analysis of renal dysfunction. Acute kidney injury was classified on the basis of creatinine levels (Kidney Disease: Improving Global Outcomes criteria) as stage 1 (≥1.5× but <2× baseline), stage 2 (≥2× but <3× baseline), or stage 3 (>3× baseline). When available, cystatin C, a marker of kidney function unaffected by MATE-1, was used to evaluate the glomerular filtration rate (GFR). RESULTS: We identified 863 patients receiving MATEi TKIs including crizotinib (39%, n = 333), lorlatinib (17%, n = 144), cabozantinib (10%, n = 87), selpercatinib (10%, n = 82), capmatinib (9%, n = 77), brigatinib (6%, n = 53), entrectinib (5%, n = 45), tepotinib (5%, n = 41), and pralsetinib (0.1%, n = 1). Of the 90 patients (10%) with acute kidney injury, Kidney Disease: Improving Global Outcomes stages 1, 2, and 3 were observed in 72% (n = 65), 21% (n = 19), and 7% (n = 6) of patients, respectively. Concurrently drawn creatinine and cystatin C levels on TKI therapy were available for 17 patients. In most cases (n = 15 of 17), the calculated GFR was higher using cystatin C versus creatinine. The percentage of patients whose GFR was higher using cystatin C versus creatinine by less than 10 mL/min, 10 to 19 mL/min, 20 to 29 mL/min, and more than or equal to 30 mL/min was 27% (n = four of 15), 20% (n = three of 15), 20% (n = three of 15), and 33% (n = five of 15), respectively. Long-term data in three patients that spanned 3 years revealed that GFR was higher using cystatin C versus creatinine in 96% (n = 49 of 51) of all time points. Using a virtual clinical trial GFR cutoff of 40 mL/min, the percentage of eligible patients rose from 41% (n = seven of 17) using creatinine calculations to 71% (n = 12 of 17) using cystatin C calculations. CONCLUSIONS: The calculated GFR in patients with cancer receiving MATEi TKIs was higher in almost all cases when using cystatin C. When serum creatinine level seems elevated in patients receiving MATE-1 inhibitors, we recommend recalculating GFR using cystatin C before searching for other etiologies of kidney injury and reducing or stopping TKI therapy.

Patient-Specific Pharmacokinetics and Dasatinib Nephrotoxicity.

BACKGROUND: Dasatinib has been associated with nephrotoxicity. We sought to examine the incidence of proteinuria on dasatinib and determine potential risk factors that may increase dasatinib-associated glomerular injury. METHODS: We examined glomerular injury through urine albumin-creatinine ratio (UACR) in 82 patients with chronic myelogenous leukemia who were on tyrosine-kinase inhibitor therapy for at least 90 days. t tests were used to compare mean differences in UACR, while regression analysis was used to assess the effects of drug parameters on proteinuria development while on dasatinib. We assayed plasma dasatinib pharmacokinetics using tandem mass spectroscopy and further described a case study of a patient who experienced nephrotic-range proteinuria while on dasatinib. RESULTS: Participants treated with dasatinib ( n =32) had significantly higher UACR levels (median 28.0 mg/g; interquartile range, 11.5-119.5) than participants treated with other tyrosine-kinase inhibitors ( n =50; median 15.0 mg/g; interquartile range, 8.0-35.0; P < 0.001). In total, 10% of dasatinib users exhibited severely increased albuminuria (UACR >300 mg/g) versus zero in other tyrosine-kinase inhibitors. Average steady-state concentrations of dasatinib were positively correlated with UACR ( ρ =0.54, P = 0.03) and duration of treatment ( P = 0.003). There were no associations with elevated BP or other confounding factors. In the case study, kidney biopsy revealed global glomerular damage with diffuse foot process effacement that recovered on termination of dasatinib treatment. CONCLUSIONS: Exposure to dasatinib was associated with a significant chance of developing proteinuria compared with other similar tyrosine-kinase inhibitors. Dasatinib plasma concentration significantly correlated with higher risk of developing proteinuria while receiving dasatinib. PODCAST: This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_09_08_CJN0000000000000219.mp3.

Dasatinib nephrotoxicity correlates with patient-specific pharmacokinetics.

Introduction: Dasatinib has been associated with nephrotoxicity. We sought to examine the incidence of proteinuria on dasatinib and determine potential risk factors that may increase dasatinib-associated glomerular injury. Methods: We examine glomerular injury via urine albumin-to-creatinine ratio (UACR) in 101 chronic myelogenous leukemia patients who were on tyrosine-kinase inhibitor (TKI) therapy for at least 90 days. We assay plasma dasatinib pharmacokinetics using tandem mass spectroscopy, and further describe a case study of a patient who experienced nephrotic-range proteinuria while on dasatinib. Results: Patients treated with dasatinib (n= 32) had significantly higher UACR levels (median 28.0 mg/g, IQR 11.5 - 119.5) than patients treated with other TKIs (n=50; median 15.0 mg/g, IQR 8.0 - 35.0; p < 0.001). In total, 10% of dasatinib users exhibited severely increased albuminuria (UACR > 300 mg/g) versus zero in other TKIs. Average steady state concentrations of dasatinib were positively correlated with UACR (ρ = 0.54, p = 0.03) as well as duration of treatment ( p =0.003). There were no associations with elevated blood pressure or other confounding factors. In the case study, kidney biopsy revealed global glomerular damage with diffuse foot process effacement that recovered upon termination of dasatinib treatment. Conclusions: Exposure to dasatinib is associated a significant chance of developing proteinuria compared to other similar TKIs. Dasatinib plasma concentration significantly correlates with increased risk of developing proteinuria while receiving dasatinib. Screening for renal dysfunction and proteinuria is strongly advised for all dasatinib patients.

Outcomes of renal transplantation in patients with AL amyloidosis: an international collaboration through The International Kidney and Monoclonal Gammopathy Research Group.

Effective systemic therapies suppress toxic light chain production leading to an increased proportion of patients with light chain (AL) amyloidosis who survive longer albeit with end-stage renal disease. There is a critical need to identify patients in this population who benefit from renal transplantation. This multicenter, observational study from five countries includes 237 patients with AL amyloidosis who underwent renal transplantation between 1987 and 2020. With a median follow-up of 8.5 years, the median overall survival from renal transplantation was 8.6 years and was significantly longer in patients with complete and very good partial hematologic responses (CR + VGPR) compared to less than VGPR (9 versus 6.8 years; HR: 1.5, P = 0.04 [95% CI: 1-2.1]) at renal transplantation. Median graft survival was 7.8 years and was better in the CR + VGPR group (8.3 vs 5.7 years, HR: 1.4, P = 0.05 [95% CI: 1-2]). The frequency and time to amyloid recurrence in the graft was also lower (16% vs 37%, p = 0.01) and longer (median time not achieved vs 10 years, p = 0.001) in the CR + VGPR group. Comparing CR vs. VGPR there was no difference in overall or graft survival. Although 69 patients (29%) experienced hematologic relapse, treatment effectively prevented graft loss in the majority (87%). Renal transplantation in selected AL amyloidosis patients is associated with extended overall and renal graft survival. Patients with hematologic CR or VGPR have the most favorable outcomes, and these patients should be considered for renal transplantation.

Acute Kidney Injury in the Modern Era of Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND AND OBJECTIVES: AKI is a major complication of allogeneic hematopoietic stem cell transplantation, increasing risk of nonrelapse mortality. AKI etiology is often ambiguous due to heterogeneity of conditioning/graft versus host disease regimens. To date, graft versus host disease and calcineurin inhibitor effects on AKI are not well defined. We aimed to describe AKI and assess pre-/post-hematopoietic transplant risk factors in a large recent cohort. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We performed a single-center, retrospective study of 616 allogeneic hematopoietic cell transplant recipients from 2014 to 2017. We defined AKI and CKD based on Kidney Disease Improving Global Outcomes (KDIGO) criteria and estimated GFR using the Chronic Kidney Disease Epidemiology Collaboration equation. We assessed AKI pre-/post-hematopoietic transplant risk factors using cause-specific Cox regression and association of AKI with CKD outcomes using chi-squared test. AKI was treated as a time-dependent variable in relation to nonrelapse mortality. RESULTS: Incidence of AKI by day 100 was 64%. Exposure to tacrolimus and other nephrotoxins conferred a higher risk of AKI, but tacrolimus levels were not associated with severity. Reduced-intensity conditioning carried higher AKI risk compared with myeloablative conditioning. Most stage 3 AKIs were due to ischemic acute tubular necrosis and calcineurin inhibitor nephrotoxicity. KRT was initiated in 21 out of 616 patients (3%); of these 21 patients, nine (43%) recovered and five (24%) survived to hospital discharge. T cell-depleted transplants, higher baseline serum albumin, and non-Hispanic ethnicity were associated with lower risk of AKI. CKD developed in 21% (73 of 345) of patients after 12 months. Nonrelapse mortality was higher in those with AKI (hazard ratio, 2.77; 95% confidence interval, 1.8 to 4.27). CONCLUSIONS: AKI post-hematopoietic cell transplant remains a major concern. Risk of AKI was higher with exposure to calcineurin inhibitors. T cell-depleted hematopoietic cell transplants and higher serum albumin had lower risk of AKI. Of the patients requiring KRT, 43% recovered kidney function. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_09_07_CJN19801220.mp3.

Kidney injury and disease in patients with haematological malignancies.

Acute kidney injury (AKI) is common in patients with cancer, especially in those with haematological malignancies. Kidney injury might be a direct consequence of the underlying haematological condition. For example, in the case of lymphoma infiltration or extramedullary haematopoiesis, it might be caused by a tumour product; in the case of cast nephropathy it might be due to the presence of monoclonal immunoglobulin; or it might result from tumour complications, such as hypercalcaemia. Kidney injury might also be caused by cancer treatment, as many chemotherapeutic agents are nephrotoxic. High-intensity treatments, such as high-dose chemotherapy followed by haematopoietic stem cell transplantation, not only increase the risk of infection but can also cause AKI through various mechanisms, including viral nephropathies, engraftment syndrome and sinusoidal obstruction syndrome. Some conditions, such as thrombotic microangiopathy, might also result directly from the haematological condition or the treatment. Novel immunotherapies, such as immune checkpoint inhibitors and chimeric antigen receptor T cell therapy, can also be nephrotoxic. As new therapies for haematological malignancies with increased anti-tumour efficacy and reduced toxicity are developed, the number of patients receiving these treatments will increase. Clinicians must gain a good understanding of the different mechanisms of kidney injury associated with cancer to better care for these patients.

Hypophosphatemia and FGF23 tumor-induced osteomalacia in two cases of metastatic breast cancer.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by factor-induced dysregulation of phosphate and vitamin D metabolism resulting in alterations in bone formation, leading to bone pain and fractures. While the true incidence is likely underestimated, less than 500 cases of TIO have been reported since initial description in 1947. TIO cases have classically been associated with mesenchymal tumors of bone and soft tissue, but have also rarely been linked to malignant tumors, with scant reports implicating non-mesenchymal tumors. TIO is mediated through inappropriate tumor overproduction of fibroblast growth factor 23 (FGF23). Increased FGF23 secretion leads to hypophosphatemia by (1) reduced phosphate reabsorption via activation of the proximal renal tubular epithelial cells to internalize sodium phosphate cotransporters and (2) reduced activation of vitamin D3 via inhibition of the renal enzyme 1-α hydroxylase. Low circulating levels of active vitamin D lead to reduced intestinal phosphate absorption and impaired mineralization of osteoid matrix. TIO in breast cancer poses a distinct diagnostic challenge due to the common adjunct oncologic management with bone protection therapy such as denosumab or bisphosphonates. These agents can be culprits of hypophosphatemia and hypocalcemia, rendering timely diagnosis of TIO difficult. Delay of diagnosis of TIO can result in worsening functional status, and early morbidity and mortality. To date, there has been one prior case report of TIO in breast cancer, and herein we describe two additional cases of TIO in this setting.

A multi-center study on safety and efficacy of immune checkpoint inhibitors in cancer patients with kidney transplant.

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.

Acute Kidney Injury after CAR-T Cell Therapy: Low Incidence and Rapid Recovery.

Chimeric antigen receptor (CAR) T cell therapy using engineered cytotoxic T cells has shown promising responses in various hematologic malignancies. Cytokine release syndrome (CRS) and immune effector cell-associated neurologic syndrome (ICANS) are recognized toxicities of CAR-T, whereas kidney injury remains less well recognized. The objective of the present study was to identify the incidence of acute kidney injury (AKI) after CAR-T cell therapy, potential risk factors, and recovery of kidney function. We performed a retrospective review of 46 adult patients with non-Hodgkin lymphoma treated with CAR-T therapy between February 2018 and February 2019 at our institution. Serum creatinine values before CAR-T therapy through day 100 were used to assess AKI, as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria: grade 1, 1.5- to <2-fold of baseline; grade 2, 2- to <3-fold of baseline; grade 3, ≥3-fold of baseline. CRS and ICANS were graded using the consensus criteria of the American Society of Transplantation and Cellular Therapy. The overall incidence of CRS was 78.3% (95% confidence interval [CI], 66% to 90.5%), of whom 13% (95% CI, 3.3% to 22.8%) developed grade 3-4 CRS, whereas the overall incidence of ICANS was lower at 45.7% (95% CI, 3.1% to 60.3%). The cumulative incidence of any grade AKI by day 100 was 30% (95% CI, 16.9% to 43.9%), with a grade 1 AKI incidence of 21.7% (95% CI, 9.7% to 33.8%) and a grade 2-3 AKI incidence of 8.7% (95% CI, .4% to 17%). No patients developed severe AKI necessitating renal replacement therapy. Patients with previous autologous or allogeneic stem cell transplantation, those requiring intensive care unit level care and with grade 3-4 CRS had a higher incidence of AKI. Most patients recovered, with kidney function returning to baseline within 30 days. We conclude that with early recognition and management of CAR-T complications, the incidence of AKI is low, the severity of injury is mild, and most patients recover kidney function within 30 days.

Incidence and Risk Factors for Acute and Chronic Kidney Injury after Adult Cord Blood Transplantation.

Although cord blood transplantation (CBT) extends allograft access, patient comorbidities, chemoradiation, and nephrotoxic medications all contribute to acute kidney injury (AKI) risk. We analyzed AKI in adult myeloablative CBT recipients who underwent transplantation from 2006 to 2017 for hematologic malignancies using cyclosporine A (CSA)/mycophenolate mofetil immunosuppression. Maximum grades of AKI were calculated using Kidney Disease: Improving Global Outcomes (grade 1, 1.5 to <2-fold; grade 2, 2 to <3-fold; or grade 3, ≥3-fold over baseline) definitions. In total, 153 patients (median 51 years [range, 23-65], 114/153 [75%] acute leukemia, 27/153 [18%] African, 88/153 [58%] cytomegalovirus seropositive, median age-adjusted hematopoietic cell comorbidity index 3 [range, 0-9], median pretransplant albumin 4.0 g/dL [range, 2.6-5.2]) underwent transplantation. The day 100 cumulative incidence of grade 1-3 AKI was 83% (95% confidence interval [CI], 77%-89%) (predominantly grade 2, median onset 40 days, range 0 to 96), and grade 2-3 AKI incidence was 54% (95% CI, 46%-62%) (median onset 43 days, range 0 to 96). Mean CSA level preceding AKI onset was high (360 ng/mL, target range 300-350). In multivariate analysis, African ancestry, addition of haploidentical CD34+ cells, low day -7 albumin, critical illness/intensive care admission, and nephrotoxic drug exposure (predominantly CSA and/or foscarnet) were associated with AKI. In a day 100 landmark analysis, 6% of patients with no prior AKI had chronic kidney disease (CKD) at 2 years versus 43% with prior grade 1 and 38% with prior grade 2-3 AKI (overall P= .02). Adult CBT recipients are at significant AKI risk, and AKI is associated with increased risk of CKD. Prevention strategies, early recognition, and prompt intervention are critical to mitigate kidney injury.

Vitamin D and Clinical Outcomes in Dialysis.

Most dialysis patients are vitamin D deficient, including deficiencies in both activated vitamin D (1, 25-dihydroxyvitamin D) and the less active 25-hydroxyvitamin D. These and other abnormalities associated with chronic kidney disease (CKD), if they remain untreated, lead to secondary hyperparathyroidism and bone changes, such as osteitis fibrosa cystica. Activated vitamin D has been proven to decrease parathyroid hormone (PTH) levels in dialysis patients and is currently used for this indication. There are multiple other potential "pleotrophic" effects associated with vitamin D therapy. These include associations with lower all-cause and cardiovascular mortality, lower rates of infections and improved glycemic indexes. Meta-analyses of multiple observational studies have shown activated vitamin D therapy to be associated with improved survival. Observational data also suggest fewer infections and better glucose control. There have been no randomized clinical trials powered to evaluate mortality or other clinical outcomes. Small trials of nutritional vitamin D (ergocalciferol and cholecalciferol) showed increases in 25-hydroxyvitamin D levels without hypercalcemia or hyperphosphatemia, even when given in addition to activated vitamin D therapy. While activated vitamin D therapy is associated with improved outcomes, it also leads to higher fibroblast growth factor 23 (FGF-23) levels, which may be detrimental in dialysis patients. Further research is needed to evaluate whether activated or nutritional vitamin D therapy are beneficial in dialysis patients for outcomes other than secondary hyperparathyroidism.