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.

Management of Patients with Acute Methotrexate Nephrotoxicity with High-Dose Leucovorin.

BACKGROUND: Acute kidney injury complicating high-dose methotrexate (HDMTX) therapy increases the risk for severe mucositis, myelosuppression, and death. It is unclear whether high-dose leucovorin and supportive therapy without the use of glucarpidase can reduce toxicity from HDMTX. STUDY DESIGN: The charts of all patients at Memorial Sloan Kettering Cancer Center whose methotrexate (MTX) drug levels at 48 or 72 hours after administration were 10 times or more the toxic level were reviewed between January 2000 and December 2011. RESULTS: Eighty-eight patients (median age 51 years, range 9-90 years) who received 100 courses of HDMTX were identified. Serum creatinine increased by 2-fold from baseline (median, range 1- to 10-fold), but all patients recovered kidney function. Serum levels of MTX were 69 µmol/L (median, range 2.2-400), 6.9 µmol/L (1.3-64), and 2.0 µmol/L (0.05-26) at 24, 48, and 72 hours, respectively, after administration. A statistically significant correlation existed between MTX levels at 48, 72, 96, and 120 hours after administration but not between 24 and 72 hours or subsequent time points. High-dose leucovorin was given in 81% of courses in accordance with institutional protocols in most cases. Myelosuppression was present in 42%; grade III or higher neutropenia in 29%, and thrombocytopenia in 25%. Infectious complications, oral mucositis, and diarrhea occurred in 21%, 17%, and 6% of patients, respectively. Five deaths occurred, none directly attributed to complications from MTX administration. Seven additional patients received glucarpidase at the discretion of a treating physician during the study period, and results are reported separately. CONCLUSION: Patients who had 100 episodes of HDMTX-associated acute kidney injury were treated with a strategy that only included usual supportive measures and high-dose leucovorin. No deaths were directly attributed to complications related to HDMTX. Glucarpidase, an expensive drug, may not be necessary for a significant number of patients.

Long-Term Renal Outcomes after Cisplatin Treatment.

BACKGROUND AND OBJECTIVES: Nephrotoxicity remains the dose-limiting side effect of cisplatin, an effective chemotherapeutic agent with applications across diverse tumor types. This study presents data on renal outcomes across multiple tumor types in 821 adults. We report on incidence of AKI, initial and long-term changes in eGFR after cisplatin, and relationships between cumulative dose, initial eGFR, age, sex, and long-term renal function. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a retrospective study of adult patients treated with cisplatin from January 1, 2000 to September 21, 2011 who had survived ≥5 years after initial dose. The Modification of Diet in Renal Disease equation was used to calculate eGFR. AKI was defined as an increase from the baseline creatinine of >25% within 30 days after the first cycle of cisplatin. Chi-squared tests were done to evaluate the relationships between categorical or ordinal variables; ANOVAs or t tests were used to evaluate continuous or categorical variables. Changes in eGFR over time were evaluated in a growth curve model. RESULTS: Mean follow-up was 6 years (25th and 75th percentiles, 4 and 9 years). AKI occurred in 31.5% of patients, with a median initial decline in eGFR of 10 ml/min per 1.73 m(2) (25th and 75th percentiles, -41.5 and -23.3 ml/min per 1.73 m(2)). At any time point after the first cycle of cisplatin, <3% of patients progressed to eGFR<29 ml/min per 1.73 m(2), and none were known to be on dialysis. Age was associated with a higher risk for AKI after cisplatin. Compared with age <25 years old, the odds ratios for AKI versus no AKI are 1.22 for >26-44 years old (95% confidence interval [95% CI], 0.60 to 2.4), 1.54 for >45-65 years old (95% CI, 0.78 to 3), and 2.96 for >66 years old (95% CI, 1.4 to 6.1). The lowest dose categories of cisplatin (≤100 and 101-250 mg/m(2)) are associated with increases in eGFR (P=0.06 and P=0.02, respectively) compared with the highest dose category (>701 mg/m(2)). CONCLUSIONS: This is the largest study of adult patients with cancer who received cisplatin for treatment across multiple tumor types. Most patients experience small but permanent declines in eGFR, but none progressed to ESRD requiring hemodialysis.

Clinicopathological spectrum of kidney diseases in cancer patients treated with vascular endothelial growth factor inhibitors: a report of 5 cases and review of literature.

Recently, cancer therapies have been supplemented by vascular endothelial growth factor (VEGF) inhibitors as anti-angiogenic agents. However, kidney-related adverse reactions associated with these agents clinically manifest as hypertension and proteinuria, the most severe form being thrombotic microangiopathy (TMA). We present the spectrum of pathological features in VEGF inhibitor-associated kidney disease. Clinicopathological findings of kidney disease were retrospectively studied in 5 cancer patients treated with anti-VEGF agents. Although 4 cases received bevacizumab (anti-VEGF-A), one was given sorafenib (small molecule tyrosine kinase inhibitor affecting VEGF-R2). All patients presented with acute kidney injury, hypertension, and/or proteinuria. All kidney biopsies showed recent and chronic endothelial injury of varying severity and vascular sclerosis, including 2 with typical active features of TMA. Furthermore, acute tubular injury with focal necrosis was seen in all cases. While administration of VEGF inhibitor was discontinued in 4 cases, it was resumed for 5 more doses, following steroid therapy in 1 case. Cessation of VEGF inhibitor therapy was successful in reversing anemia and led to improvement of hypertension and proteinuria in 4 of the 5 cases. One case with TMA progressed to end-stage renal disease. A range of renal pathologic lesions secondary to endothelial injury are noted often accompanied by acute tubular damage following anti-VEGF therapy, the most severe being TMA. While most of the clinical manifestations are reversible with discontinuation of therapy, the role of other nephrotoxic chemotherapeutic agents in enhancing renal injury including severe TMA and other host factors with possible poor outcome should be considered.

Long term renal toxicity of ifosfamide in adult patients--5 year data.

Ifosfamide is indicated as first line treatment in a variety of solid tumours in adults. It is known to be nephrotoxic and is often used following therapy with, or as concomitant therapy with other potent nephrotoxins. To date, there are sparse case reports on the incidence of acute kidney injury (AKI) or chronic kidney disease (CKD) in adults exposed to ifosfamide. The available data on the long term renal complications for patients exposed to ifosfamide are thus based entirely on the paediatric population. The aim of this study was to assess the long term effects of ifosfamide exposure on renal function in an adult population and to determine if there are any treatment or patient specific factors that contribute to long term nephrotoxicity. The mean decline in estimated glomerular filtration rate (eGFR) following the first cycle of ifosfamide was 15 ml/min/1.73 m(2). Thereafter, there was a slower but steady decline in eGFR. No patient progressed to end stage renal disease (ESRD). Patient age and concomitant exposure to carboplatin were the only two factors which significantly affected eGFR. This represents the only long term study on the nephrotoxicity of ifosfamide in adults.

A retrospective observational study on the use of capecitabine in patients with severe renal impairment (GFR <30 mL/min) and end stage renal disease on hemodialysis.

Capecitabine (Xeloda) is an orally administered precursor of 5'deoxy-5-fluorouridine, which is a preferentially activated to 5-fluorouracil in tumors. It is used in the treatment of colorectal, gastric, and breast cancers. Based on a single Phase II trial, which included a total of 4 patients with severe renal impairment (GFR <30 mL/min), the manufacturer issued a 'Dear Doctor' letter contraindicating the use of capecitabine in these patients since a high rate of grade 3 and 4 adverse events were observed and because these patients tolerated shorter treatment durations.(1) We retrospectively studied 12 patients with a GFR <30 mL/min, including 2 patients with end stage renal disease on hemodialysis, who received capecitabine for mean duration of 7.1 months (1-26 months). The mean serum creatinine at the time of initiation of the drug was 2.63 mg/dL (1.8-6.4 mg/dL) and mean GFR was 20.9 mL/min (8-29 mL/min). Two patients remained on capecitabine after they progressed to end stage renal disease (ESRD) requiring hemodialysis (HD) for an additional 17 and 6 months, respectively. Most patients reported grade 1 and 2 adverse effects (AE), 2 patients reported grade 3 diarrhea and one patient died while on treatment with capecitabine. The starting dose ranged from 250 to 1000 mg/m(2), given twice daily at variable intervals. Dose modifications, with reductions of up to 50% of the starting dose, were made following reports of AEs. Serum tumor marker levels and/or follow up imaging studies were available on 9 patients. Response to capecitabine was documented in 4 patients, stable disease in 2, and disease progression in 3. We conclude that, with close monitoring of their clinical and chemical data, and with dose modification based on reported AEs, capecitabine can be safely administered to patients with severe renal impairment, including patients on hemodialysis.

Nephrotoxicities associated with the use of tyrosine kinase inhibitors: a single-center experience and review of the literature.

BACKGROUND: Sunitinib is an oral multitargeted tyrosine kinase receptor inhibitor (MTKI) used for the treatment of renal cell carcinoma. These small-molecule agents inhibit signaling through receptor tyrosine kinases such as vascular endothelial growth factor receptor, platelet-derived growth factor receptor and cytokine stem cell factor receptor, among others. Although the development of these novel molecular-targeted agents represents a substantial advance in the treatment of metastatic cancer, the spectrum of their adverse effects may be broader than initially predicted. METHOD: We performed a retrospective chart review of patients who had received sunitinib and developed renal insufficiency. RESULTS: We describe 4 patients with renal cell carcinoma and 1 patient with transitional cell carcinoma treated with sunitinib who experienced various degrees of nephrotoxicity including hypertension, proteinuria, thrombotic microangiopathy, and acute and chronic kidney injury which resolved upon cessation of MTKI. CONCLUSIONS: Nephrologists and oncologists should be aware of the potential for toxic renal effects, and we recommend guidelines for early recognition and treatment of these conditions in patients receiving MTKI.

Chronic kidney disease, thrombotic microangiopathy, and hypertension following T cell-depleted hematopoietic stem cell transplantation.

Chronic kidney disease (CKD) is now an accepted long-term complication of allogeneic hematopoietic stem cell transplantation. Calcineurin inhibitors (CNI), which are used for prophylaxis and treatment of graft-versus-host disease (GVHD), have been associated with the development of nephrotoxicity. Hypertension (HTN) and thrombotic microangiopathy (TMA) are 2 comorbidities linked to CKD. T cell depletion (TCD) of stem cell grafts can obviate the need for the use of CNI. We conducted a retrospective analysis of 100 patients who underwent TCD transplantation: 30 in group A were conditioned without total-body radiation (TBI) and 70 in group B received a TBI containing regimen. None of the patients received CNI. The median age was 55.5 and 45 years for groups A and B, respectively. Eleven patients developed TMA, all in group B. The 2-year cumulative incidence of sustained CKD was 29.2% and 48.8% in group A and group B, respectively, with a mean follow-up of at least 21 months. CKD free survival was better in the non-TBI group (P = .046). Multivariable survival analysis revealed that exposure to TBI, older age, and TMA were risk factors for CKD. The incidence of new onset or worsening HTN was 6.7% and 25.7% (P = .03) in group A and B, respectively. The use of TBI (P = .0182) and diagnosis of TMA (P = .0006) predisposed patients to the development of HTN using univariable logistic regression models. Thus, despite the absence of CNI, a proportion of these older patients in both groups developed CKD and HTN.

Feasibility trial of letrozole in combination with bevacizumab in patients with metastatic breast cancer.

PURPOSE: Preclinical models suggest that the use of anti-vascular endothelial growth factor (anti-VEGF) therapy with antiestrogens may prevent or delay the development of endocrine therapy resistance. We therefore performed a feasibility study to evaluate the safety of letrozole plus bevacizumab in patients with hormone receptor-positive metastatic breast cancer (MBC). METHODS: Patients with locally advanced breast cancer or MBC were treated with the aromatase inhibitor (AI) letrozole (2.5 mg orally daily) and the anti-VEGF antibody bevacizumab (15 mg/kg intravenously every 3 weeks). The primary end point was safety, defined by grade 4 toxicity using the National Cancer Institute Common Toxicity Criteria, version 3.0. Secondary end points included response rate, clinical benefit rate, and progression-free survival (PFS). Prior nonsteroidal AIs (NSAIs) were permitted in the absence of progressive disease. RESULTS: Forty-three patients were treated. After a median of 13 cycles (range, 1 to 71 cycles), select treatment-related toxicities included hypertension (58%; grades 2 and 3 in 19% and 26%), proteinuria (67%; grades 2 and 3 in 14% and 19%), headache (51%; grades 2 and 3 in 16% and 7%), fatigue (74%; grades 2 and 3 in 19% and 2%), and joint pain (63%; grades 2 and 3 in 19% and 0%). Eighty-four percent of patients had at least stable disease on an NSAI, confounding efficacy results. Partial responses were seen in 9% of patients and stable disease >or= 24 weeks was noted in 67%. Median PFS was 17.1 months. CONCLUSION: Combination letrozole and bevacizumab was feasible with expected bevacizumab-related events of hypertension, headache, and proteinuria. Phase III proof-of-efficacy trials of endocrine therapy plus bevacizumab are in progress (Cancer and Leukemia Group B 40503).

Phase I trial of bevacizumab plus escalated doses of sunitinib in patients with metastatic renal cell carcinoma.

PURPOSE: Both bevacizumab and sunitinib target the vascular endothelial growth factor pathway and demonstrate activity against advanced renal cell carcinoma (RCC). In this phase I study, the maximum-tolerated dose (MTD) and safety of sunitinib in combination with bevacizumab were examined in patients with advanced RCC. PATIENTS AND METHODS: Three cohorts of three to six patients were treated with escalated doses of daily oral sunitinib (ie, 25 mg, 37.5 mg, 50 mg) for 4 weeks followed by a 2-week break and with fixed doses of bevacizumab (10 mg/kg) intravenously once every 2 weeks. Dose-limiting toxicities (DLTs) were assessed during the first cycle to determine the MTD, and an expanded cohort was treated to obtain additional safety information. RESULTS: Of 26 study participants, 25 received treatment at one of three dose levels. Grade 4 hemorrhage, identified as a DLT, occurred in one patient in each of cohorts 2 and 3. The MTD was determined to be sunitinib 50 mg/bevacizumab 10 mg/kg, but chronic therapy at this dose level frequently resulted in grades 3 to 4 hypertension and hematologic and vascular toxicities. Overall, 48% of patients discontinued treatment because of adverse events. One complete and 12 partial responses were observed, which provided an objective response rate of 52%. CONCLUSION: In this phase I trial of patients with metastatic RCC, the combination of sunitinib and bevacizumab caused a high degree of hypertension and vascular and hematologic toxicities at the highest dose level. We do not plan to pursue additional study of this regimen at these doses in patients with RCC.

Ifosfamide may be safely used in patients with end stage renal disease on hemodialysis.

Background. Pharmacokinetic data on clearance of ifosfamide in hemodialysis patients are limited. Consequently, these patients are excluded from therapy with this agent. We review the outcomes for patients at our institution with end stage renal disease on dialysis who received ifosfamide for metastatic sarcoma. Patients and Methods. We treated three patients with end stage renal disease on hemodialysis with escalating doses of ifosfamide. Data on radiographic response to therapy, WBC and platelet counts, signs or symptoms of infection, neuropathy and bladder toxicity are reported. Starting doses of ifosfamide were based on review of the literature available with subsequent modifications based on each patient's prior exposure to myelosuppressive agents and on symptoms of neurotoxicity and the degree of myelosuppression following each cycle of chemotherapy. Results. Myelosuppression was the most common side effect from therapy, but no patient developed a life threatening infection, neurotoxicity, or hematuria. One patient developed epistaxis in the setting of thrombocytopenia while on warfarin therapy. All patients had clinical evidence for therapeutic response and two had documented radiographic improvement following ifosfamide administration. Conclusion. Ifosfamide can be used safely in combination with hemodialysis in patients with end stage renal disease.

Cetuximab therapy and symptomatic hypomagnesemia.

We report that patients treated with cetuximab, a monoclonal antibody against the epithelial growth factor receptor (EGFR), occasionally develop a magnesium wasting syndrome with inappropriate urinary excretion. We first observed this phenomenon in a 34-year-old male patient with metastatic colorectal cancer who developed profound fatigue and symptomatic hypocalcemia and hypomagnesemia while on cetuximab plus irinotecan therapy. Other medications with the potential to cause magnesium wasting had not been administered. Intravenous magnesium supplementation was required for the duration of cetuximab therapy, but electrolyte abnormalities resolved after discontinuation of treatment. This case prompted review of serum chemistry reports for a consecutive case series of 154 colorectal cancer patients treated with cetuximab. Thirty-four patients (22%) had at least one serum magnesium measurement during cetuximab treatment, and six had grade 3 (< 0.9 mg/dL) and two had grade 4 (< 0.7 mg/dL) hypomagnesemia. Because EGFR is strongly expressed in the kidney, particularly in the ascending limb of the loop of Henle where 70% of filtered magnesium is reabsorbed, EGFR blockade may interfere with magnesium transport. Because symptoms may be rapidly ameliorated with supplementation, we suggest that, when fatigue or hypocalcemia is encountered during cetuximab therapy, serum magnesium level be measured and repleted as necessary.

Efforts to control the errant products of a targeted in vivo generator.

Alpha-particle immunotherapy by targeted alpha-emitters or alpha-emitting isotope generators is a novel form of extraordinarily potent cancer therapy. A major impediment to the clinical use of targeted actinium-225 (225Ac) in vivo generators may be the radiotoxicity of the systemically released daughter radionuclides. The daughters, especially bismuth-213 (213Bi), tend to accumulate in the kidneys. We tested the efficacy of various pharmacologic agents and the effect of tumor burden in altering the pharmacokinetics of the 225Ac daughters to modify their renal uptake. Pharmacologic treatments in animals were started before i.v. administration of the HuM195-225Ac generator. 225Ac, francium-221 (221Fr), and 213Bi biodistributions were calculated in each animal at different time points after 225Ac generator injection. Oral metal chelation with 2,3-dimercapto-1-propanesulfonic acid (DMPS) or meso-2,3-dimercaptosuccinic acid (DMSA) caused a significant reduction (P < 0.0001) in the renal 213Bi uptake; however, DMPS was more effective than DMSA (P < 0.001). The results with DMPS were also confirmed in a monkey model. The renal 213Bi and 221Fr activities were significantly reduced by furosemide and chlorothiazide treatment (P < 0.0001). The effect on renal 213Bi activity was further enhanced by the combination of DMPS with either chlorothiazide or furosemide (P < 0.0001). Competitive antagonism by bismuth subnitrate moderately reduced the renal uptake of 213Bi. The presence of a higher target-tumor burden significantly prevented the renal 213Bi accumulation (P = 0.003), which was further reduced by DMPS treatment (P < 0.0001). Metal chelation, diuresis with furosemide or chlorothiazide, and competitive metal blockade may be used as adjuvant therapies to modify the renal accumulation of 225Ac daughters.

Acute renal failure in cancer patients.

Acute renal failure (ARF) is defined as a sudden decrease in glomerular filtration rate leading to an acute rise in blood urea nitrogen and serum creatinine levels. It is a serious complication of cancer and constitutes a major source of morbidity and mortality. Current data suggest that ARF has the potential to substantially jeopardize the chances of cancer patients receiving optimal treatment and a potential cure. The pathways leading to ARF in cancer patients are common to the development of ARF in other conditions. However, ARF may also develop due to aetiologies arising from cancer treatment or the disease itself, including: nephrotoxic chemotherapy agents, post-renal obstruction, compression and infiltration by malignancy, tumour lysis syndrome, uric acid, sepsis and contrast agent nephropathy. This review provides a comprehensive overview of the causes of ARF in patients with cancer and guidance on how to prevent and treat this condition. Ultimately, the key to managing ARF in cancer patients is to ensure that a multidisciplinary approach provides adequate assessment, appropriate preventative measures and early intervention.

High-dose calcitriol, zoledronate, and dexamethasone for the treatment of progressive prostate carcinoma.

BACKGROUND: Preclinical and clinical data have suggested that high-dose calcitriol (1,25-dihydroxycholecalciferol) has activity against prostate carcinoma. Pulse-dosed calcitriol and dexamethasone may maximize tolerability and efficacy. The authors examined the toxicity of pulse-dosed calcitriol with zoledronate and with the addition of dexamethasone at the time of disease progression. METHODS: Patients with progressive prostate carcinoma were eligible for the current study. In cohorts of 3-6 patients, calcitriol was administered for 3 consecutive days per week, starting at a dose of 4 microg per day. Doses were escalated to 30 microg per day. Intravenous zoledronate (4 mg) was administered monthly. Dexamethasone could be added to the regimen at disease progression. Toxicities, markers of bone turnover, plasma calcitriol levels, and clinical outcomes were recorded. RESULTS: Thirty-one patients were treated in cohorts that were defined by the calcitriol dose administered (4, 6, 8, 10, 14, 20, 24, or 30 microg). Seven patients received dexamethasone. Three patients had their doses reduced due to calcium-related laboratory findings. Patients tolerated therapy well, even in the 30 microg cohort; therefore, a maximum tolerated dose was not defined. Peak plasma levels observed in the 24 microg and 30 microg cohorts ranged from 391 to 968 pg/mL. Minimal antitumor effects were observed. CONCLUSIONS: Calcitriol was well tolerated at doses up to and including 30 microg 3 times per week in combination with intravenous zoledronate 4 mg monthly, with or without dexamethasone, in patients with progressive prostate carcinoma. Peak plasma levels in the 24 microg and 30 microg cohorts were greater than the levels associated with antitumor effects preclinically. Due to the cumbersome dosing schedule and the lack of significant activity observed, Phase II trials of this regimen are not planned.