Long-term Renal Toxicity Research Articles

Combining Multiple Omics with Molecular Dynamics Reveals SCP2-Mediated Cytotoxicity Effects of Aflatoxin B1 in SW480 Cells.

Aflatoxins belong to a class of mycotoxins, among which aflatoxin B1 (AFB1) has detrimental effects on the health of both animals and humans. It is associated with long-term exposure-induced carcinogenicity, hepatotoxicity, renal toxicity, neurotoxicity, and immunosuppressive properties, resulting in a variety of diseases. The intestine is the first barrier for human exposure to AFB1, but limited investigations have been conducted to clarify the underlying mechanisms of intestinal cytotoxicity. The mechanism of AFB1-induced cytotoxicity was investigated in this study using an integrated approach combining transcriptome, proteome, and metabolome analysis along with molecular dynamics simulation. After exposing SW480 cells to 50 μM AFB1 for 72 h, the transcriptome, proteome, and metabolome exhibited significant enrichment in pathways associated with oxidative stress, fatty acid and lipid metabolism, and glutathione metabolism. The experimental results demonstrated that AFB1 significantly reduces SW480 cells viability, and induces oxidative stress, calcium overload, mitochondrial damage, and lipid metabolism disorders.

Disseminated Histoplasmosis with Secondary Hemophagocytic Lymphohistiocytosis in a Renal Transplant Recipient on Belatacept-based Immunosuppression

Effective post-transplant immunosuppression is essential to induce tolerance to allogeneic tissues and promote long-term graft survival. However, suppression of the immune system significantly increases the risk of opportunistic infections. In addition to the ongoing challenge of balancing graft survival and preventing infections, previous gold-standard calcineurin inhibitor-based immunosuppression also posed an increased risk of nephrotoxicity, cardiac disease, and diabetes. Belatacept is approved as an alternative to calcineurin inhibitor-based regimens. Although belatacept has improved cardiovascular and metabolic adverse events in renal transplant patients’ but it carries a notably higher risk of long-term graft survival and renal toxicity, similar to calcineurin inhibitor-based regimens. However, there may be an increased risk of infections with its mechanism of action. We present a case of a 62-year-old female who developed disseminated histoplasmosis 18 months after being on belatacept-based immunosuppression after a deceased donor renal transplant for end-stage renal disease secondary to focal segmental glomerulosclerosis. Grocott Methenamine Stain (GMS) of peripheral blood smear showed intracellular yeast in neutrophils, consistent with histoplasmosis. Disseminated histoplasmosis was confirmed with positive bronchoalveolar lavage (BAL) and urine culture. The patient later developed hemophagocytic lymphohistiocytosis (HLH) secondary to immunosuppression and disseminated histoplasmosis. The patient succumbed to the disease despite maximal medical therapy. To our knowledge, there is one other published report of disseminated histoplasmosis in a patient with belatacept-based immunosuppression. The unique feature of this case is the development of HLH secondary to disseminated histoplasmosis while on belatacept. Further research is needed to evaluate the need for antifungal prophylaxis in patients on belatacept therapy.

#2754 Long-term renal outcomes in ICI-associated acute interstitial nephritis: a comprehensive comparative study

Abstract Background and Aims Immune checkpoint inhibitors (ICI) have transformed cancer treatment, but they may lead to immune-mediated acute interstitial nephritis (ICI-AIN), in 2-5% of patients. About 35-40% show full kidney function recovery three months post ICI-AIN. Limited evidence exists for long-term renal toxicity. The unknown difference in long-term renal function evolution between partial and complete recovery of the acute episode in ICI-AIN is an unexplored area for future research. Additionally, there's no comparative study on the long-term renal function evolution between ICI-AIN and cases associated with other drugs (Drug-AIN) or autoimmune causes (AI-AIN). Method Retrospective, descriptive and observational study. The medical records of all AIN cases diagnosed in the Nephrology Unit of the Bellvitge University Hospital between 2010 and 2023 were reviewed. Longitudinal data on treatments, comorbidities and kidney function were collected. Data was analyzed using descriptive statistics, Chi-square tests, Mann-Whitney U tests and Kaplan Meier analyses. Results A total of 94 out of 96 screened patients were diagnosed with AIN (AI-AIN n = 26; Drug-AIN n = 30; ICI-AIN n = 38). Of those, 89.4% were biopsy-confirmed. Median follow-up was 36.64 months (IQR 12.32-74.28). There were not differences in baseline serum creatinine (sCreat) across the groups, defined as sCreat 6 months prior to AIN. At diagnosis, sCreat was lower in ICI-AIN compared to Drug-AIN (267.62 ± 116.44 vs 553.20 ± 317.46, p < 0.001), but significant differences were not found comparing to AI-AIN. There were not differences in the cumulative dose and days of treatment with prednisone between the three groups. In the first year, 35.5% of ICI-AIN patients and 10.3% with Drug-AIN returned to baseline kidney function (p = 0.020). Over the course of three years, 45.9% reverted to baseline in the ICI-AIN cohort compared to 18.5% in the Drug-AIN cohort (p = 0.023). This trend continued at 5 years, with 45.9% in ICI-AIN and 22.2% in Drug-AIN recovering to baseline (p = 0.051). The proportion of patients who recovered baseline kidney function was comparable between the group diagnosed with ICI-AIN and the group diagnosed with AI-AIN at all evaluated time points. Kaplan-Meier analysis at 1, 3, and 5 years of follow-up revealed a shorter time to sCreat recovery to baseline in the ICI-AIN group compared to the Drug-AIN group, with Log-rank (Mantel-Cox) p-values of 0.016, 0.004, and 0.006, respectively. On the contrary, Kaplan-Meier analysis at the same time points did not reveal differences in time to basal sCreat recovery in ICI-AIN compared to AI-AIN. Among the evaluated variables, only baseline sCreat influenced the recovery of baseline kidney function in in the univariate analysis, with an odds ratio of 0.95 (95% CI 0.903-1, p-value 0.049) in the ICI-AIN group. The mean nadir sCreat and estimated glomerular filtration rate (eGFR) after treating AIN were comparable between ICI-AIN and Drug-AIN patients (nadir sCreat: 107.46 µmol/L and 102.24 µmol/L, respectively; nadir eGFR: 61.89 ml/min and 56.96 ml/min, respectively; p-value ns). However, ICI-AIN patients reached nadir renal function more rapidly after treatment initiation (10.99 vs. 28.06 months, p-value = 0.020). After reaching nadir function, 73.7% of ICI-AIN patients showed decline, similar to Drug-AIN (73.3%) and AI-AIN (88.5%, p ns). Yet, ICI-AIN patients had a higher yearly eGFR decline post-nadir compared to Drug-AIN (−17.05 (ml/min)/year vs. −3.99 (ml/min)/year, p-value 0.006) and autoimmune AIN (−4.09 (ml/min)/year, p-value 0.009). Conclusion In summary, the results of our study suggest that ICI-AIN patients demonstrate a distinctive pattern of recovery after the acute episode and long-term decline in kidney function after reaching the nadir kidney function compared to the Drug-AIN and AI-AIN groups. They exhibit a faster recovery to nadir kidney function but experience a higher yearly decline post-nadir in eGFR. The influence of baseline sCreat on recovery underscores the importance of considering individual patient characteristics in predicting outcomes and optimizing kidney function before initiating treatment with ICI.

Long-term Nephrotoxicity after PRRT: Myth or Reality.

Rationale: The kidneys are commonly considered as the potential dose-limiting organ for peptide receptor radionuclide therapy (PRRT), making the risk of nephrotoxicity a primary concern. This retrospective analysis with prospective documentation and long-term follow-up aims to assess the risk of nephrotoxicity after PRRT in a large cohort of patients with neuroendocrine neoplasms (NENs) treated at our institution over the past 18 years. Methods: A total of 1361 NEN patients treated with 1-10 cycles of 177Lu-DOTA-TOC/-NOC/-TATE, 90Y-DOTA-TOC/-NOC/-TATE, DUO-PRRT (sequential administration of 90Y- and 177Lu-), or TANDEM-PRRT (combination of 90Y- and 177Lu- on the same day concomitantly) were included in this analysis. All parameters were prospectively documented in a structured database comprising over 250 items per patient and retrospectively analyzed. Kidney function, including serum creatinine, blood urea nitrogen, cGFR, and electrolytes, was evaluated before each PRRT cycle and during follow-up. Restaging was regularly performed at 6-month intervals until death. Treatment-related adverse events were graded according to the Common Terminology Criteria for Adverse Events (CTCAE v.5.0). Results: Between 2000 and 2018, a total of 5409 cycles of PRRT were administered to 1361 NEN patients. Follow-up after complete treatment was available for 1281 patients receiving 4709 cycles of PRRT, with a median follow-up time of 69.2 months (interquartile range, 32.8-110.5 months) and a maximum follow-up time of 175 months. Baseline creatinine levels were normal in 1039/1281 (81.1%) subjects, while grade 1 (G1) renal insufficiency was present in 221/1281 (17.3%) prior to PRRT. G2 was present in 19/1281 (1.5%), and G3 in 2/1281 (0.2%). After treatment, the proportion of G3/G4 grade patients only increased from 0.2% to 0.7%. Mean creatinine levels increased from a baseline of 0.90 ± 0.30 to 1.01 ± 0.57 mg/L (80.0 ± 26.7 to 89.4 ± 50.8 μmol/L) after treatment. In our main analysis cohort of 1244 patients (4576 cycles), 200 patients experienced an increase in CTCAE creatinine grade. Age, number of treatment cycles, type of radionuclides, and length of follow-up time were the main factors affecting CTCAE creatinine grading after treatment. When comparing the subgroups treated with different radionuclides, the risk of nephrotoxicity after 90Y treatment alone and the 90Y/177Lu combination group was higher than after 177Lu treatment alone. In the 90Y treatment subgroup, the two significant risk factors for an increased CTCAE creatinine grade were identified to be age (≥60) and a long follow-up time. Conclusions: This retrospective analysis with prospective documentation in a large cohort of 1281 NEN patients receiving 4709 cycles of PRRT co-administered with renal protection, treated through the individualized approach at a single institution over 18 years, did not reveal any evidence of long-term PRRT-related renal toxicity. The results of our study suggest that with the use of proper renal protection, nephrotoxicity due to PRRT is more likely a myth than a reality.

Long-Term Toxicity after Total Body Irradiation-Based Conditioning Regimens for Allogeneic Stem Cell Transplantation

Total body irradiation (TBI) is an integral component of many conditioning regimens prior to allogeneic hematopoietic stem cell transplantation (HSCT). Few studies have investigated long-term sequelae. A large series of patients undergoing myeloablative and non-myeloablative regimens was studied. Adult patients undergoing allogeneic HSCT utilizing TBI-based conditioning regimens from 1995-2020 at our institution were included. Baseline treatment-related factors and long-term toxicities (developing, or persisting beyond, 6 months after HSCT) were collected. The cumulative incidence of long-term toxicities and overall survival (OS) were calculated. Cox regression was used to assess for predictors of toxicity. Five hundred fifty-two patients were analyzed: 378 myeloablative (typically 13.5 Gy/9fx) and 174 non-myeloablative (typically 2 Gy/1fx) TBI recipients. Median follow-up was 7.4 years for surviving patients. Cumulative incidences of long-term toxicities at 5 and 10 years are included in the Table. The most common toxicities were: pulmonary- infectious pneumonia and respiratory failure NOS; cardiac- heart failure and myocardial infarction; other endocrine- adrenal insufficiency and testosterone deficiency. The most common secondary malignancy was non-melanoma skin cancer. The proportion of all toxicities that were high-grade (3-5) for myeloablative and non-myeloablative regimens, respectively, were: pulmonary (65%, 52%), cardiac (66%, 39%), renal (23%, 27%), and other endocrine (3%, 18%). Increasing number of chemotherapy regimens (p = 0.05) and umbilical cord donor (p = 0.02) were associated with long-term pulmonary toxicity. Male sex (p = 0.03), increasing number of chemotherapy regimens (p<0.01), and elevated creatinine after transplant (p<0.01) were associated with long-term renal toxicity. Cataract development was associated with increasing age at transplant (p = 0.02). OS (5 years) was 40% (42% -myeloablative; 33%-non-myeloablative). Allogeneic HSCT, often preceded by TBI-based conditioning regimens, has significant survivorship challenges. Recipients of non-myeloablative regimens are still at risk of significant long-term multisystem toxicity despite much lower doses of TBI and chemotherapy. Pre-transplant factors such as cumulative chemotherapy exposure and age at transplant were associated with some toxicities.

Renal Safety of Long-term Tenofovir Disoproxil Fumarate Treatment in Patients With Chronic Hepatitis B.

Data on renal safety of tenofovir disoproxil fumarate (TDF) treatment among individuals with chronic hepatitis B (CHB) are inconsistent. The current study aimed to assess the effect of long-term TDF treatment on renal outcomes in adult patients with CHB. From a CHB cohort in Ethiopia, we included 233 patients treated with TDF and 126 untreated controls. Levels of creatinine and creatinine clearance over time were described in patients with and without TDF treatment. Linear mixed effects models with a treatment × time interaction were used to investigate the effect of TDF on creatinine and creatinine clearance. In treated patients only, change in creatinine and creatinine clearance was estimated separately in the first year as compared with subsequent years via linear mixed effects models. Median follow-up in the treated group was 51 months (IQR, 27-72), and 75% of patients were male (median age, 33 years; IQR, 26-40). Median follow-up in the untreated group was 69 months (IQR, 66-72), and 48% of participants were male (median age, 33 years; IQR, 27-41). We found no change in creatinine over time in TDF-treated patients as compared with a slight increase in untreated patients (P interaction = .003). There was a decrease in creatinine clearance over time in both groups, which was stronger in patients without TDF treatment (P interaction = .007). In TDF-treated patients, changes in creatinine and creatinine clearance occurred mainly within the first 12 months after treatment initiation. This study showed no evidence of long-term renal toxicity of TDF treatment in patients with CHB.

Recombinant α1-Microglobulin (rA1M) Protects against Hematopoietic and Renal Toxicity, Alone and in Combination with Amino Acids, in a 177Lu-DOTATATE Mouse Radiation Model.

177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) is used clinically to treat metastasized or unresectable neuroendocrine tumors (NETs). Although 177Lu-DOTATATE is mostly well tolerated in patients, bone marrow suppression and long-term renal toxicity are still side effects that should be considered. Amino acids are often used to minimize renal radiotoxicity, however, they are associated with nausea and vomiting in patients. α1-microglobulin (A1M) is an antioxidant with heme- and radical-scavenging abilities. A recombinant form (rA1M) has previously been shown to be renoprotective in preclinical models, including in PRRT-induced kidney damage. Here, we further investigated rA1M's renal protective effect in a mouse 177Lu-DOTATATE model in terms of administration route and dosing regimen and as a combined therapy with amino acids (Vamin). Moreover, we investigated the protective effect of rA1M on peripheral blood and bone marrow cells, as well as circulatory biomarkers. Intravenous (i.v.) administration of rA1M reduced albuminuria levels and circulatory levels of the oxidative stress-related protein fibroblast growth factor-21 (FGF-21). Dual injections of rA1M (i.e., at 0 and 24 h post-177Lu-DOTATATE administration) preserved bone marrow cellularity and peripheral blood reticulocytes. Administration of Vamin, alone or in combination with rA1M, did not show any protection of bone marrow cellularity or peripheral reticulocytes. In conclusion, this study suggests that rA1M, administered i.v. for two consecutive days in conjunction with 177Lu-DOTATATE, may reduce hematopoietic and kidney toxicity during PRRT with 177Lu-DOTATATE.

Carboplatin and hypomagnesemia: Is it really a problem?

Carboplatin has largely replaced cisplatin in ovarian/peritoneal/tubal cancer (OC) due to comparable activity and reduced toxicity, particularly nephrotoxicity and hypomagnesemia. Anecdotally hypomagnesemia occurs commonly with carboplatin, however there are limited data available regarding frequency or severity. To quantify incidence and severity of hypomagnesemia in patients receiving carboplatin-based chemotherapy for OC; to explore a dose-response relationship with carboplatin and assess potential confounding variables. A retrospective single-center review of all OC patients receiving carboplatin-based chemotherapy as first/subsequent line between 2012 and 2018 was performed. Data on patient/disease characteristics, potential confounders (gastrointestinal/renal impairment, premorbid hypomagnesemia and concomitant medications), dose, electrolytes, and magnesium replacement were collected. One hundred four of 144 (72%) patients had at least one hypomagnesemia event, 11 of 104 (11%) grade 2, and 11 of 104 (11%) grade 3/4 in severity. Multivariate analysis showed a significant association between hypomagnesemia and treatment duration (P<.001). Premorbid hypomagnesemia was associated with a significantly longer duration and higher grade of hypomagnesemia (P=.021 and P<.001, respectively). Vomiting, diarrhea, and confounding medications were associated with hypomagnesemia (P=.019 and P=.028, respectively). Fourteen percent of hypomagnesemia events never resolved suggesting a significant cohort post-carboplatin are at risk of long-term renal toxicity. The effect of magnesium replacement could not be accurately assessed due to limited documentation of replacement. Hypomagnesemia is common in patients receiving carboplatin-based chemotherapy for OC, and although generally mild, a significant minority were severe. Several high-risk groups were identified including patients with premorbid hypomagnesemia, vomiting, diarrhea, or taking certain medications. Further research is warranted to understand when hypomagnesemia is clinically relevant and determine the impact of interventions.

Outcomes After Proton Therapy for Treatment of Pediatric High-Risk Neuroblastoma

Patients with high-risk neuroblastoma (HR-NBL) require radiation to the primary tumor site and sites of persistent metastatic disease. Proton radiation therapy (PRT) may promote organ sparing, but long-term outcomes have not been studied. Sequential patients with HR-NBL received PRT: 2160cGy (relative biological effectiveness) to primary tumor bed and persistent metastatic sites, with 3600cGy (relative biological effectiveness) to gross residual disease. From September 2010 through September 2015, 45 patients with HR-NBL received PRT after systemic therapy, primary tumor resection, and high-dose chemotherapy with stem cell rescue. Median age was 46months at the time of PRT (range, 10months to 12years); 23 patients (51%) were male. Primary tumors were adrenal in 40 (89%); 11 (24%) received boost. Ten metastatic sites in 8 patients were radiated. Double scattered proton beams were used for 19 (42%) patients, in combination with x-rays for 2 (5%). The remaining 26 (58%) received pencil beam scanning, available since January 2013. We observed 97% freedom from primary site recurrence at 3, 4, and 5years. Overall survival rates were 89%, 80%, and 80% and disease-free survival rates were 77%, 70%, and 70%, at 3, 4, and 5years, respectively. With median follow-up of 48.7months from diagnosis (range, 11-90months) for all patients (57.4months for those alive), 37 (82%) patients are alive, and 32 (71%) are without evidence of disease. One patient experienced locoregional recurrence; the remaining 12 (27%) experienced relapse at distant, nonradiated sites. Acute toxicities during treatment were mainly grade 1. No patient has experienced World Health Organization grade 3 or 4 long-term renal or hepatic toxicity. Pencil beam scanning plans required less planning time and resources than double scattered plans. We observe excellent outcomes in patients treated with PRT for HR-NBL from 2010 through 2015, with 82% of patients alive and 97% free of primary site recurrence. No patient has experienced long-term renal or liver toxicity. This treatment maximizes normal tissue preservation and is appropriate for this patient population.

Somatostatin Receptor 2-Targeting Compounds.

The molecular imaging and treatment of neuroendocrine tumors (NETs) with radiolabeled somatostatin analogs represent a milestone in the development of theranostic compounds. Whole-body scintigraphy with 111In-pentetreotide has revolutionized the diagnosis and staging of NETs and the evaluation of treatment outcomes. At present, diagnostic accuracy with positron-emitting radionuclides is greater than 90%. Peptide receptor radionuclide therapy (PRRT) has become a well-accepted treatment for patients with well-differentiated inoperable or metastatic NETs and disease progression after first-line treatment. Disease control rates (complete or partial remission or stable disease in patients with formerly progressive disease) of up to 95%, with a low incidence of long-term hematologic and renal toxicity, have been reported. In a recently published randomized trial, compared with intensified treatment of midgut NETs with long-acting and repeatable octreotide, PRRT reduced the hazard of disease progression and death by 79%. Upcoming developments in PRRT include the use of somatostatin receptor antagonists and α-emitting radionuclides, which may further enhance treatment outcomes.

Preventing long-term tenofovir renal toxicity by pharmacokinetic assessment

Tenofovir is the active metabolite of tenofovir disoproxil fumarate (TDF), a commonly used antiretroviral agent in HIV treatment and in HIV preexposure prophylaxis. After a long-term exposure, TDF is associated with kidney impairment. In the D:A:D study cohort of HIV-infected patients (22 603 HIV-infected patients with baseline estimated glomerular filtration rate (eGFR) 90 ml/min per 1.73 m), tenofovir exposure was associated after adjustment with an increased relative risk (1.18 a year) of developing chronic kidney disease (CKD) defined by the occurrence of an eGFR below 70 ml/min per 1.73 m [1]. Recent studies also suggested that tenofovir use in preexposure prophylaxis might also be associated with a weak decline in eGFR, a mean decrease in eGFR after 60 months of treatment was 6 ml/min in the Bangkok Tenofovir study [2], and around 2 ml/min per 1.73 m during a median follow-up of 18 months in Partners Prep Study [3]. The decline in eGFR associated with tenofovir use is not always reversible after treatment cessation [4]. Tenofovir has a mitochondrial toxicity in tubular cells, leading to kidney tubular dysfunction (KTD) [5]. KTD affects 10.6–19% of the patients receiving tenofovir [6,7]. Tubular tenofovir toxicity is probably dose dependent. Indeed, an association between high-trough tenofovir plasma concentrations and KTD (defined by hypophosphatemia, hypouricemia, nondiabetic glucosuria, b-2 microglobulinuria, or a-1 microglobulinuria) was previously observed [6,7]. However, a decrease in eGFR may be observed without evidence for KTD. It is crucial to identify mechanisms and risk factors of tenofovir renal toxicity. Tenofovir penetrates in tubular cells by several tubular transporters. Polymorphisms in genes encoding for tubular transporters organic cationic transporter 1, multidrug resistant protein 2 (MRP-2) and 4 (MRP-4) were associated with increased tenofovir plasma concentrations and increased risk of KTD or of decrease in eGFR [8–11].

Efficacy, safety and pharmacokinetics of tenofovir disoproxil fumarate in virologic-suppressed HIV-infected children using weight-band dosing.

Tenofovir disoproxil fumarate (TDF) is approved for children but concerns remain about long-term renal and bone toxicity. We evaluated the efficacy, safety and pharmacokinetics of TDF in treatment-experienced children during 96 weeks. This was a prospective, open-label study in HIV-infected children 3-18 years of age (≥15 kg), with viral suppression on their first-line regimen without tenofovir. Children were given TDF/lamivudine/efavirenz once daily at entry; TDF was prescribed according to weight bands. Age-, gender- and CD4-matched controls receiving TDF-sparing regimens were concomitantly enrolled. Tenofovir pharmacokinetic assessment was performed at week 4. CD4 counts, HIV-1 RNA viral load and safety assessments were determined at baseline, 24, 48 and 96 weeks. Eighty children were enrolled (40 per group); 35 (44%) were male. Median age was 12.2 (range 3.1-17.7) years. The median administered dose was 214 mg/m. Tenofovir geometric mean AUC0-24 hours, Cmax and C24 hours were 2.66 [90% confidence interval (CI) 2.49-2.84] μg hours/mL, 0.26 (0.24-0.29) μg/mL and 0.057 (0.052-0.062) μg/mL, respectively. Estimated glomerular filtration rate did not significantly change overtime. The fractional excretion of calcium slightly increased but fractional excretion of phosphate was unchanged among children in TDF group. The bone mineral density Z score decreased in the first 24 weeks of TDF treatment and was stable afterward. The TDF group had lower cholesterol levels (P = 0.001). Thirty-nine of 40 children remained virologically suppressed. No serious adverse event related to tenofovir. TDF substitution in children and adolescents who were otherwise stable while receiving a first-line nonnucleoside reverse transcriptase inhibitor-based regimen achieved adequate exposure without clinically significant renal or bone adverse events over 96 weeks. While reassuring, these preliminary safety findings may not exclude delayed effects on renal function and bone density.

Cyclophosphamide compared with ifosfamide in consolidation treatment of standard-risk Ewing sarcoma: results of the randomized noninferiority Euro-EWING99-R1 trial.

Relative efficacy and toxicity of cyclophosphamide compared with ifosfamide are debatable. The Euro-EWING99-R1 trial asked whether cyclophosphamide may replace ifosfamide in combination with vincristine and dactinomycin (vincristine, dactinomycin, and cyclophosphamide [VAC] v vincristine, dactinomycin, and ifosfamide [VAI]) after an intensive induction chemotherapy containing vincristine, ifosfamide, doxorubicin, and etoposide (VIDE) in standard-risk localized disease (NCT00020566). Standard-risk Ewing sarcomas were localized tumors with either a good histologic response to chemotherapy (< 10% cells) or small tumors (< 200 mL) resected at diagnosis or receiving radiotherapy alone as local treatment. Patients entered the trial after six VIDE+1 VAI courses. Allocated treatment was either 7 VAC courses with 1.5 g/m(2) of cyclophosphamide or seven VAI-courses with 6 g/m(2) ifosfamide. The limit of noninferiority was set at -8.5% for the 3-year event-free survival rate (EFS), equivalent to 1.43 in terms of the hazard ratio of event (HR(event)). This large international trial recruited 856 patients between February 2000 and March 2010 (n = 431 receiving VAC and n = 425 receiving VAI). With a median follow-up of 5.9 years, the 3-year EFSs were 75.4% and 78.2%, respectively, the 3-year EFS difference was -2.8% (91.4% CI, -7.8 to 2.2%), the HR(event) was 1.12 (91.4% CI, 0.89 to 1.41), and the HR(death) was 1.09 (91.4% CI, 0.84 to 1.42; intention-to-treat). The HR(event) was 1.22 (91.4% CI, 0.96 to 1.54) on the per-protocol population. Major treatment modifications were significantly less frequent in the VAC arm (< 1%) than in the VAI arm (7%), mainly resulting from toxicity. Patients experienced more frequent thrombocytopenia in the VAC arm (45% v 35%) but fewer grade 2 to 4 acute tubular toxicities (16% v 31%). Cyclophosphamide may be able to replace ifosfamide in consolidation treatment of standard-risk Ewing sarcoma. However, some uncertainty surrounding the noninferiority of VAC compared with VAI remains at this stage. The ongoing comparative evaluation of long-term renal and gonadal toxicity is crucial to decisions regarding future patients.

High-dose Interleukin-2 Therapy for Metastatic Renal Cell Carcinoma: A Contemporary Experience

To present our experience of high-dose interleukin-2 (HDIL-2) in a high-volume National Cancer Institute-designated center for patients with metastatic renal cell carcinoma (mRCC). Patients with mRCC who received HDIL-2 monotherapy as a first- or second-line therapy during 2004-2011 were identified. Demographics, pathologic variables, renal function, time until the start of HDIL-2 therapy, number of cycles (1-3), responses (complete response, partial response, stable disease, and progressive disease), and primary renal cell carcinoma treatment were analyzed. Progression-free survival and overall survival (OS) were determined. Of 906 patients in the kidney cancer database, 91 patients with mRCC were treated with HDIL-2 and 18 patients (20.5%) underwent prior cytoreductive nephrectomy. Median age was 51 years, and 73.9% were men. Median follow-up was 45 months. Pretreatment renal function impairment led to more treatment cycles (2-3) than in those with adequate initial kidney function (92.3% vs 50.6%, respectively; P = .002). Lower tumor stage correlated with a better response (P = .023) and with longer time from diagnosis to initiation of HDIL-2 (P = .011). Complications included hypotension (67.4%), renal impairment (63%), impaired liver function (42.4%), and thrombocytopenia (31.5%). Four patients (4.5%) had a complete response, 10 (11.4%) had a partial response, and 28 (31.8%) had a stable disease. Median progression-free survival and OS were 8.6 and 35.5 months, respectively. The estimated 2-year OS rate was 60.6%. Incorporating HDIL-2 therapy in the treatment strategies for mRCC added to the patients' survival in this series. HDIL-2 therapy is well tolerated in patients with pre-existing renal impairment with no long-term renal toxicity.

Astatine-211 Conjugated To Anti-CD20 Monoclonal Antibody Eliminates B-Cell Lymphoma In a Mouse Model

Stem cell rescue after myeloablative doses of beta particle emitting radiolabeled monoclonal antibodies targeting CD20 antigen can lead to remissions in up to 95% of lymphoma patients who previously failed conventional combination chemotherapy. While encouraging, toxicities with beta particle radioimmunotherapy (RIT) are significant and ∼50% of patients ultimately relapse. Higher doses of absorbed radiation to tumors have correlated with a reduced risk of disease recurrence but dose limiting toxicities prevent escalation. A potential advantage of alpha particle emitting radionuclides is the release of large amounts of energy linearly over a few cell diameters (∼50-80 mm) resulting in irreparable double-strand DNA breaks that overwhelm cellular repair mechanisms. As a result, alpha particles confer a unique capacity to kill individual targeted cells while causing minimal radiation damage to surrounding tissues. To explore alpha-emitter conjugated anti-CD20 RIT, a closo-decaborate(2-) [B10] labeling reagent was developed as a radiolabeling platform capable of providing critical stability to alpha particle-labeled biomolecules. 211At was chosen as a therapeutic radionuclide based on its high linear energy transfer, biologically relevant t1/2 (∼7.2 hr) and absence of toxic daughter radionuclide decay byproducts. Cell binding assays using CD20-expressing Ramos tumor cells demonstrated that B10 conjugated to the anti-CD20 monoclonal antibody (mAb) 1F5 (B10-1F5) was specific and that astatination did not impair antibody binding (211At-B10-1F5 binding was equivalent to 125I-B10-1F5). Blood clearance was similar for 125I-1F5, 211At-B10-1F5 and 125I-B10-1F5 in athymic nude- Foxn1nu mice (23.87 ±5.13 % injected dose/gram [ID/g], 19.41 ±3.27 %ID/g and 19.80 ±1.44% ID/g respectively) at 17 hr post infusion. In tissue biodistribution studies using nude mice bearing Ramos flank tumor xenografts (10 x106 cells injected) radioactivity was measured in blood, tumor and nonspecific organs harvested 24 hours after injection (n=5/group). Animals received either 125I-1F5, 211At-B10-1F5 and 125I-B10-1F5 (co-injected) or isotype matched control mAb 211At- B10-HB8181 and125I-B10-HB8181(co-injected). Measured activity in tumors was three-fold higher for 125I-1F5, 125I-B10-1F5 and 211At-B10-1F5 (7.62 ± 2.09%ID/g, 7.53 ± 1.59%ID/g and 9.28 ± 1.85%ID/g respectively) than for 125I-B10-HB8181 and 211At-B10-HB8181 controls (2.87 ± 0.35%ID/g and 3.45 ± 0.58%ID/g respectively). In non-target organs no appreciable difference in measured activity was seen with either 211At- or 125I-labeled B10-1F5 and their respective controls. Subsequent therapy studies performed in nude mice bearing Ramos flank tumor xenografts demonstrated only a moderate survival advantage after 211At-B10-1F5 [data not shown]. This finding was consistent with the hypothesis that the alpha particle's short path length may not be ideally suited to models of “bulky” disease. In contrast, therapy studies using disseminated Ramos and Granta tumor cells introduced into NOD-SCID mice suggest a role for alpha particle based RIT in “non-bulky” disease models. In these studies NOD-SCID animals received 1x106 tumor cells iv 48 hours prior to 211At-B10-1F5 (10 μCi or 15 μCi) or control 211At-B10-HB8181 (n=10/group). Stem cell rescue was performed 48 hours after the RIT. Eighty days after treatment 80% of animals receiving 15 μCi of 211At-B10-1F5 and 70% of animals in the 10 μCi treatment group were alive and tumor free while no animals in the non-binding 211At-B10-HB8181 (10 μCi or 15 μCi) control groups survived beyond day 47 (Figure). Blood counts, serum creatinine and transaminase levels measured in 211At-B10-1F5 treated animals ∼180 days after RIT demonstrated no significant long-term bone marrow, renal or liver toxicity. 211At-B10-1F5 can eliminate CD20 expressing tumor cells in this mouse model and further study appears to be warranted. Disclosures: No relevant conflicts of interest to declare.

Long‐term effect of chronic intravenous and inhaled nephrotoxic antibiotic treatment on the renal function of patients with cystic fibrosis

Cystic fibrosis (CF) patients have numerous infectious exacerbations requiring prolonged antibiotic treatments, some of which are nephrotoxic. Inhaled antibiotics can reach detectable serum levels. We studied the impact of chronic nephrotoxic antibiotic exposure on kidney function in CF population. We collected data retrospectively for 113 adult CF patients followed for 8.5 years. Fifty-seven (50.4%) were males and 56 (49.5%) females (mean age 31.7 years [SD 9.9]), of which 31% had diabetes and 9.7% had hypertension. Over 8.5 years follow up, there were no significant changes in blood urea nitrogen (BUN; P = 0.92) or creatinine (P = 0.2) in the whole group. 22% of patients had ≥1 episodes of acute kidney injury (AKI). The presence of AKI was associated with increased BUN (P = 0.002) and creatinine (P = 0.056) at the end of follow up. Use of intravenous colistin, gentamicin, tobramycin, or vancomycin did not correlate with increased BUN (P = 0.64; P = 0.49; P = 0.51; P = 0.47) or creatinine (P = 0.43; P = 0.49; P = 0.17; P = 0.2) after 8.5 years. Elevated tobramycin peak and trough levels did not correlate with increased BUN or creatinine. Inhaled colistin and gentamicin correlated with increased BUN (P = 0.009; P = 0.02) but not creatinine (P = 0.45; P = 0.46). Inhaled tobramycin did not correlate with increased BUN (P = 0.17) or creatinine (P = 0.58). Only inhaled colistin correlated with AKI episodes (P = 0.03). Chronic inhaled colistin and gentamicin are associated with an increase in BUN but not creatinine at the end of follow up. Inhaled colistin was associated with episodes of AKI. Well-managed intravenous use of nephrotoxic antibiotics in CF population is associated with no major long-term renal toxicity.

Nephrotoxicity profiles and threshold dose values for [177Lu]-DOTATATE in nude mice

In peptide receptor radionuclide therapy for neuroendocrine tumors the main dose-limiting tissue is found in the kidneys because of tubular reabsorption and retention of radioactivity. The aim of this study was to quantify late effects in renal cortex of nude mice exposed to high amounts of [(177)Lu]-DOTA-Tyr(3)-octreotate ([(177)Lu]-DOTATATE), and to determine whether a threshold dose value exists for these findings. Nude mice were exposed to 90, 120 or 150MBq of [(177)Lu]-DOTATATE. Renal toxicity was evaluated up to 6 months after injection. Blood samples were collected to examine renal functional markers, and after sacrifice at 6 months changes in renal morphology were explored. Tissue damage was estimated by quantifying the relative area of the different subunits in the renal cortex using point counting. Additional morphological signs of radiation damage were also noted. The absorbed doses to the kidneys were estimated by previously determined kidney pharmacokinetics and Monte Carlo simulations for different assumptions regarding the activity distribution. Increased serum creatinine and urea values indicated long-term renal toxicity. The tissue area occupied by proximal tubules decreased with increasing doses of [(177)Lu]-DOTATATE, whereas the other subunits in cortex slightly increased. The mean absorbed dose in the renal cortex for [(177)Lu]-DOTATATE was estimated to be 35-58Gy for the different groups of animals. A dose-response relationship was observed for proximal tubular damage, and a threshold dose value of 24Gy (BED 37Gy) was determined. Selective morphological changes in kidney cortex of nude mice were quantified and appeared in a dose dependent manner after injection of high amounts of [(177)Lu]-DOTATATE.

Radioimmunotherapy of breast cancer metastases with alpha-particle emitter 225Ac: comparing efficacy with 213Bi and 90Y.

alpha-Particles are suitable to treat cancer micrometastases because of their short range and very high linear energy transfer. alpha-Particle emitter (213)Bi-based radioimmunotherapy has shown efficacy in a variety of metastatic animal cancer models, such as breast, ovarian, and prostate cancers. Its clinical implementation, however, is challenging due to the limited supply of (225)Ac, high technical requirement to prepare radioimmunoconjugate with very short half-life (T(1/2) = 45.6 min) on site, and prohibitive cost. In this study, we investigated the efficacy of the alpha-particle emitter (225)Ac, parent of (213)Bi, in a mouse model of breast cancer metastases. A single administration of (225)Ac (400 nCi)-labeled anti-rat HER-2/neu monoclonal antibody (7.16.4) completely eradicated breast cancer lung micrometastases in approximately 67% of HER-2/neu transgenic mice and led to long-term survival of these mice for up to 1 year. Treatment with (225)Ac-7.16.4 is significantly more effective than (213)Bi-7.16.4 (120 microCi; median survival, 61 days; P = 0.001) and (90)Y-7.16.4 (120 microCi; median survival, 50 days; P < 0.001) as well as untreated control (median survival, 41 days; P < 0.0001). Dosimetric analysis showed that (225)Ac-treated metastases received a total dose of 9.6 Gy, significantly higher than 2.0 Gy from (213)Bi and 2.4 Gy from (90)Y. Biodistribution studies revealed that (225)Ac daughters, (221)Fr and (213)Bi, accumulated in kidneys and probably contributed to the long-term renal toxicity observed in surviving mice. These data suggest (225)Ac-labeled anti-HER-2/neu monoclonal antibody could significantly prolong survival in HER-2/neu-positive metastatic breast cancer patients.

Long-Term Renal Toxicity in Children Following Fractionated Total-Body Irradiation (TBI) Before Allogeneic Stem Cell Transplantation (SCT)

To retrospectively assess the incidence and time course of renal dysfunction in children (< or = 16 years) following total- body irradiation (TBI) before allogeneic stem cell transplantation (SCT). Between 1986 and 2003, 92 children (median age, 11 years; range, 3-16 years) underwent TBI before allogeneic SCT. 43 of them had a minimum follow-up of 12 months (median, 51 months; range, 12-186 months) and were included into this analysis. Conditioning regimen included chemotherapy and fractionated TBI with 12 Gy (n = 26) or 11.1 Gy (n = 17). In one patient, renal dose was limited to 10 Gy by customized renal shielding due to known nephropathy prior to SCT. Renal dysfunction was defined as an increase of serum creatinine > 1.25 times the upper limit of age-dependent normal. Twelve children (28%) experienced an episode of renal dysfunction after a median of 2 months (range, 1-10 months) following SCT. In all but one patient renal dysfunction was transient and resolved after a median of 8 months (range, 3-16 months). One single patient developed persistent renal dysfunction with onset at 10 months after SCT. None of these patients required dialysis. The actuarial 3-year freedom from persistent renal toxicity for children surviving > 12 months after SCT was 97.3%. The incidence of persistent renal dysfunction after fractionated TBI with total doses < or = 12 Gy was very low in this analysis.

The nephrotoxic effects of HAART

With significant reductions in mortality and risk of progression to AIDS in the era of highly active antiretroviral therapy (HAART), complications of long-standing HIV infection and treatment have become increasingly important. Such complications include the nephrotoxic effects of HAART, which are the subject of this Review. The most common nephrotoxic effects associated with HAART include crystal-induced obstruction secondary to use of protease inhibitors (mainly indinavir and atazanavir), and proximal tubule damage related to the nucleotide analog reverse transcriptase inhibitor tenofovir. Acute kidney injury (AKI) can occur following tenofovir-induced tubule dysfunction or as a result of severe mitochondrial dysfunction and lactic acidosis induced by nucleoside reverse transcriptase inhibitors. The potential insidious long-term renal toxicity of antiretroviral treatment is probably underappreciated in patients with HIV: a proportion of patients with treatment-related AKI did not recover their baseline renal function at 2-year follow-up, suggesting the possibility of permanent renal damage. Finally, nonspecific metabolic complications might increase the risk of vascular chronic kidney disease in patients on HAART. However, given the benefits of HAART, fear of nephrotoxic effects is never a valid reason to withhold antiretroviral therapy. Identification of patients with pre-existing chronic kidney disease, who are at increased risk of renal damage, enables appropriate dose modification, close monitoring, and avoidance or cautious use of potentially nephrotoxic medications.