Projected Incidence of Hepatobiliary Cancers and Trends Based on Age, Race, and Gender in the United States.

BACKGROUND: Identifying the projected incidence of hepatobiliary cancers and recognizing patient cohorts at increased risk can help develop targeted interventions and resource allocation. The expected incidence of subtypes of hepatobiliary cancers in different age groups, races, and genders remains unknown. METHODS: Historical epidemiological data from the Surveillance, Epidemiology, and End Results (SEER) database was used to project future incidence of hepatobiliary malignancies in the United States and identify trends by age, race, and gender. Patients ≥18 years of age diagnosed with a hepatobiliary malignancy between 2001 and 2017 were included. US Census Bureau 2017 National Population projects provided the projected population from 2017 to 2029. Age-Period-Cohort forecasting model was used to estimate future births cohort-specific incidence. All analyses were completed using R Statistical Software. RESULTS: We included 110381 historical patients diagnosed with a hepatobiliary malignancy between 2001 and 2017 with the following subtypes: hepatocellular cancer (HCC) (68%), intrahepatic cholangiocarcinoma (iCCA) (11.5%), gallbladder cancer (GC) (8%), extrahepatic cholangiocarcinoma (eCCA) (7.6%), and ampullary cancer (AC) (4%). Our models predict the incidence of HCC to double (2001 to 2029) from 4.5 to 9.03 per 100,000, with the most significant increase anticipated in patients 70-79 years of age. In contrast, incidence is expected to continue to decline among the Asian population. Incidence of iCCA is projected to increase, especially in the white population, with rates in 2029 double those in 2001 (2.13 vs. 0.88 per 100,000, respectively; p < 0.001). The incidence of GC among the black population is expected to increase. The incidence of eCCA is expected to significantly increase, especially among the Hispanic population, while that of AC will remain stable. DISCUSSION: The overall incidence of hepatobiliary malignancies is expected to increase in the coming years, with certain groups at increased risk. These findings may help with resource allocation when considering screening, treatment, and research in the coming years.

Role of innate immunological/inflammatory pathways in myelodysplastic syndromes and AML: a narrative review.

Dysregulation of the innate immune system and inflammatory-related pathways has been implicated in hematopoietic defects in the bone marrow microenvironment and associated with aging, clonal hematopoiesis, myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). As the innate immune system and its pathway regulators have been implicated in the pathogenesis of MDS/AML, novel approaches targeting these pathways have shown promising results. Variability in expression of Toll like receptors (TLRs), abnormal levels of MyD88 and subsequent activation of NF-κß, dysregulated IL1-receptor associated kinases (IRAK), alterations in TGF-ß and SMAD signaling, high levels of S100A8/A9 have all been implicated in pathogenesis of MDS/AML. In this review we not only discuss the interplay of various innate immune pathways in MDS pathogenesis but also focus on potential therapeutic targets from recent clinical trials including the use of monoclonal antibodies and small molecule inhibitors against these pathways.

Phase II Trial of Trifluridine/Tipiracil Plus Irinotecan in Patients with Advanced, Refractory Biliary Tract Carcinoma.

BACKGROUND: We sought to determine the safety and efficacy of trifluridine/tipiracil in combination with irinotecan in a phase II trial setting for refractory, advanced unresectable biliary tract carcinoma (BTC). METHODS: A total of 28 patients (27 were evaluable) with advanced BTCs who progressed on at least one prior systemic therapy were enrolled and were treated with trifluridine/tipiracil 25 mg/m2 (days 1-5 of 14-day cycle) and irinotecan 180 mg/m2 (day 1 of the 14-day cycle). The primary endpoint for the study was 16-week progression-free survival (PFS16) rate. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and safety were pre-specified secondary endpoints. RESULTS: Of 27 patients, PFS16 rate was 37% (10/27; 95% CI: 19%-58%), thereby meeting the criteria for success for the primary endpoint. The median PFS and OS of the entire cohort were 3.9 months (95% CI: 2.5-7.4) and 9.1 months (95% CI: 8.0-14.3), respectively. In the patients evaluable for tumor response (n = 20), the ORR and DCR were 10% and 50%, respectively. Twenty patients (74.1%) had at least one grade 3 or worse adverse event (AE), and 4 patients (14.8%) had grade 4 AEs. A total of 37% (n = 10/27) and 51.9% (n = 14/27) experienced dose reductions in trifluridine/tipiracil and irinotecan, respectively. Delay in therapy was noted in 56% of the patients while 1 patient discontinued the therapy, primarily due to hematologic AEs. CONCLUSION: The combination of trifluridine/tipiracil plus irinotecan is a potential treatment option for patients with advanced, refractory BTCs with good functional status and no targetable mutations. A larger randomized trial is needed to confirm these results. (ClinicalTrials.gov Identifier: NCT04072445).

A glimpse into the future of esophageal carcinoma in the United States: predicting the future incidence until 2040 based on the current epidemiological data.

Background: Esophageal carcinoma is the sixth most common cause of death worldwide. With the changing paradigm of esophageal carcinoma, we sought to estimate the future burden of esophageal carcinoma by histology, age, sex, and race, which could help plan prevention, control, and treatment strategies for this cancer. Methods: Surveillance, Epidemiology, and End Results (SEER) 14 registries were utilized to obtain incidence data from 2000 to 2016. We applied age-period-cohort models to estimate future esophageal carcinoma incidence rates and the estimated disease burden by multiplying incidence forecasts by corresponding US Census population projections. Results: Our forecasting study suggests that the incidence (per 100,000 persons) of esophageal adenocarcinoma for the age group 40-65 years will increase from 2.12 in 2021 to 3.86 in 2040, which corresponds to an 82% increase over the course of 19 years (3.2% per year, 95% CI: -2.3% to 9.1%). In addition, we found a considerable decrease in the incidence of esophageal squamous cell carcinoma in the current age groups 40-65 years (-2.7% per year) and >65 years (-4.6% per year). Conclusions: Preventive efforts of esophageal adenocarcinoma should primarily target males of age up to 65 years and females of current age 40 to 65 years who will make up the older age group (>65 years) in 2040.

Systemic Therapy in Advanced Hepatocellular Carcinoma: Patient Selection and Key Considerations.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide. Most patients with HCC have advanced disease at initial diagnosis, and sorafenib has been the only systemic treatment option for more than a decade in patients with advanced, unresectable HCC. However, there has been a dramatic change in the treatment algorithm in the last several years, given new drug approvals in the field. Most importantly, the combination of atezolizumab and bevacizumab has demonstrated clinically meaningful benefits in terms of response rate, progression-free survival, and overall survival compared to sorafenib in the first-line setting. Recently a phase III trial showed that the combination of durvalumab with a single dose of tremelimumab improved overall survival compared to sorafenib, while durvalumab monotherapy was found to be noninferior to sorafenib, making it an attractive alternative single agent in selected patient populations. As immunotherapy makes its way into the therapeutic landscape of HCC, other novel targeted therapies, such as lenvatinib, cabozantinib, ramucirumab, and regorafenib, have also been approved by regulatory authorities for treatment of advanced, unresectable HCC. This review article focuses on the first-line systemic treatment options for HCC while addressing some of the most important questions aimed at optimization of HCC treatment.

An evaluation of ivosidenib for the treatment of IDH1-mutant cholangiocarcinoma.

INTRODUCTION: The combination of gemcitabine and cisplatin remains the standard-of-care first-line therapeutic option in patients with the unresectable disease based on the encouraging phase II and phase III trials (ABC-02). Recently, the combination of durvalumab, gemcitabine, and cisplatin has shown modest but statistically significant improvement in median overall survival (OS) as compared to that of the gemcitabine-cisplatin combination. Systemic therapy options such as the combination of 5-flurouracil (5-FU) and oxaliplatin (FOLFOX), 5-FU and liposomal irinotecan, and trifluridine/tipiracil (TAS-102) and irinotecan have shown encouraging results. Therapies targeting FGFR2 fusions/rearrangements, BRAF mutations, microsatellite high tumors, HER2 amplifications, and IDH mutations are currently being extensively evaluated in cholangiocarcinoma with encouraging results. AREAS COVERED: We briefly discuss the recent advancements in targeted therapy approaches in cholangiocarcinoma with a special focus on ivosidenib. EXPERT OPINION: Ivosidenib is an excellent option for IDH1-mutant cholangiocarcinoma that progressed on first-line chemotherapy given its excellent tolerability and median OS benefit. However, a few questions remain unanswered - sequencing of targeted therapies, benefits of combining targeted therapy with systemic chemotherapy or with other treatment modalities, such as immunotherapy and localized therapies.

Time to first treatment is an independent prognostic factor for Multiple Myeloma (MM).

INTRODUCTION: Multiple myeloma (MM) is an incurable plasma cell neoplasm. In this study, we aimed to analyze the impact of time to initiation of systemic therapy for MM on overall survival (OS). METHODS: We identified cases diagnosed with MM from the National Cancer Database from 2004 to 2013. RESULTS: A total of 38,178 MM patients were included in the analysis. The median time to systemic therapy in our cohort was 17 days (range 0-120). The median OS for patients who initiated therapy > 30-days after diagnosis was longer than those who received it ≤ 7 days (46 vs. 27-month, p < 0.001). On multivariable analysis, patients who received treatment ≤ 7 days from diagnosis had worse mortality compared with those receiving treatment > 30 days (HR 1.5; 95% CI 1.4-1.6). CONCLUSIONS: In our study, time to initiation of systemic therapy was an independent prognostic factor in MM. Similar to other lymphoid malignancies, this metric may be a surrogate for high-risk disease in MM, and future trials may need to investigate time-to-treatment as a factor to allow enrollment of potentially sick patients.

First-Line Targeted Therapy for Hepatocellular Carcinoma: Role of Atezolizumab/Bevacizumab Combination.

Hepatocellular carcinoma (HCC) is an aggressive malignancy accounting for 90% of primary liver malignancies. Therapeutic options for HCC are primarily based on the baseline functional status, the extent of disease at presentation and the underlying liver function that is clinically evaluated by the Barcelona-Clinic Liver Cancer system and Child−Pugh score. In patients with advanced HCC, the United States Food and Drug Administration (US-FDA) approved systemic therapies include the combination of atezolizumab−bevacizumab, sorafenib, and lenvatinib in the first line setting while cabozantinib, regorafenib, ramucirumab (in patients with alfa-fetoprotein [AFP] > 400 ng/mL), pembrolizumab, nivolumab, and nivolumab-ipilimumab combination are reserved for patients who progressed on sorafenib. European Medical Agency (EMA) approved the use of atezolizumab−bevacizumab, sorafenib, and lenvatinib in the first line setting, while cabozantinib, regorafenib, and ramucirumab (in patients with alfa-fetoprotein [AFP] > 400 ng/mL) are approved for use in patients that progressed on first-line therapy. In the first line setting, sorafenib demonstrated a median overall survival (OS) benefit of 3 months as compared to that of best supportive care in randomized phase III trials, while lenvatinib was shown to be non-inferior to sorafenib. Recently, phase 3 studies with immunotherapeutic agents including atezolizumab plus a bevacizumab combination and tremelimumab plus durvalumab combination demonstrated a better OS and progression free survival (PFS) compared to sorafenib in the first-line setting, making them attractive first-line options in advanced HCC. In this review, we outlined the tumorigenesis and immune landscape of HCC in brief and discussed the role and rationale of combining immunotherapy and anti-VEGF therapy. We further expanded on potential limitations and the future directions of immunotherapy in combination with targeted agents in the management of advanced HCC.

Tumor Mutational Burden Is a Potential Predictive Biomarker for Response to Immune Checkpoint Inhibitors in Patients With Advanced Biliary Tract Cancer.

PURPOSE: Patients with advanced biliary tract cancers (BTCs) have a dismal prognosis. This multisite, single-institution study analyzed the efficacy and safety of immune checkpoint inhibitors (ICIs) in patients with advanced BTC. MATERIALS AND METHODS: The prospectively maintained institutional database was searched for patients with advanced BTC. Electronic medical records of the patients with advanced BTC treated with an ICI that included programmed death-1 or programmed death-ligand 1 blockers were retrospectively reviewed to obtain data on patient characteristics, tumor characteristics including molecular biomarkers, detailed treatment, response characteristics, survival, and toxicities. The analysis included overall response rate, survival, and correlation between survival and molecular biomarkers. RESULTS: The institutional database query identified 47 patients with advanced BTC who received at least one dose of an ICI; 11 (24%) patients in the first-line setting and the rest of the patients had refractory disease. The median age of the cohort was 62 years, and 51% were female. The overall response rate was 10.6%, with a disease control rate of 53.2%. The median progression-free survival (PFS) and overall survival were 3.6 months and 6.9 months, respectively. Biomarker analysis revealed improved PFS in patients with tumor mutational burden > 5 mutations per megabase (median PFS: 6.4 v 2.2 months; P = .0027). No unexpected adverse events were observed. CONCLUSION: ICIs are well tolerated and have modest antitumor activity in patients with advanced BTC. The study result supports the exploration of tumor mutational burden as a potential predictive biomarker for response to ICIs in patients with advanced BTC.

Isocitrate Dehydrogenase-Mutated Cholangiocarcinoma: Natural History and Clinical Outcomes.

PURPOSE: Clinical-pathologic features and natural history of patients with isocitrate dehydrogenase (IDH)-mutant intrahepatic cholangiocarcinoma (CCA) are not well characterized. Here, we sought to describe the natural history, clinical phenotype, and prognostic impact of advanced, IDH-mutated CCA. METHODS: We conducted a multicentric, retrospective analysis of patients with IDH-mutated (IDH1 or IDH2) CCA between 2010 and 2020. Median overall survival (OS) and progression-free survival (PFS) analyses were performed using the Kaplan-Meier method. Chi-square test was used to analyze disease control rate (DCR) and overall response rate (ORR). Matched controls were used for comparing survival between patients with and without IDH mutations (mIDH). RESULTS: Sixty-five patients with IDH-mutated CCA were included. All patients had intrahepatic CCA. On first-line chemotherapy, median OS and median PFS were 21.2 months and 8.3 months, respectively. Notably, median OS (32.4 v 19.5 months, P = .12) and PFS (18.0 v 8.0 months, P = .12) were not significantly affected by disease status at presentation (locally advanced v metastatic, respectively). Median OS was significantly longer in patients with mIDH (21.2 v 10.5 months; P < .01). First-line gemcitabine-containing regimens had a significantly higher DCR and ORR than non-gemcitabine-containing regimens (DCR: 75% v 33%, P = .01; ORR: 39% v 0%, P = .02). In patients receiving IDH inhibitor therapy, median PFS was 4.6 months with a DCR of 29%. CONCLUSION: CCA with mIDH confers a unique subtype resulting in a better survival compared with that of counterparts. IDH inhibitors represent a promising therapeutic option in later lines of therapy in this subgroup.

Dermatologic Manifestations of Endocrine Disorders.

Endocrine disorders are known to involve all organ systems of the body, including the skin. The cutaneous manifestations of endocrine disorders can range from common findings such as acanthosis nigricans, pretibial myxedema, acne, hirsutism, hyper or hypopigmentation to rare cutaneous findings such as miliaria rubra, calciphylaxis, lentigines, and calcinosis cutis. These cutaneous symptoms can sometimes be the presenting symptoms or can even be pathognomonic of the underlying endocrine condition. In some cases, the cutaneous symptoms from an underlying endocrine abnormality may be the most prominent. These symptoms can significantly affect the quality of life of individuals. Often, individuals may seek health care from a dermatologist or primary care physician for isolated skin symptoms. Therefore, it is imperative for physicians to recognize the skin symptoms as the manifestation of the endocrine disorder for prompt diagnosis and treatment of the underlying endocrine disorder.

Management of well-differentiated neuroendocrine tumors.

Neuroendocrine tumors (NETs) are a heterogeneous group of epithelial neoplasms with predominantly neural and endocrine differentiation that have the ability to produce peptide hormones and other biologically active substances. The histologic characterization of NETs based on differentiation and grading is crucial to determining prognosis and treatment. Surgery still offers the best chance of cure for patients with NETs, and tumor resection is the preferred approach when possible. For locally advanced or metastatic disease, approaches to treatment can vary widely depending on the extent of disease and goals of therapy. A better understanding of the biology of NETs acquired over the last decade has facilitated the development of targeted therapies, such as everolimus and a variety of tyrosine kinase inhibitors. Furthermore, the field of theranostics has led to dramatic improvements in our diagnostic and treatment abilities. Chemotherapy has a role in the treatment of NETs, evidenced by the benefit shown with the combination of temozolomide and capecitabine to treat pancreatic NETs. Somatostatin analogues are a mainstay of treatment because they reduce secretory products and have antiproliferative effects on NET cells. In this work, we aim to review the landscape for the diagnosis and treatment of well-differentiated NETs.

FGFR Inhibitors in Oncology: Insight on the Management of Toxicities in Clinical Practice.

Fibroblast Growth Factor receptor (FGFR) pathway aberrations have been implicated in approximately 7% of the malignancies. As our knowledge of FGFR aberrations in cancer continues to evolve, FGFR inhibitors emerged as potential targeted therapeutic agents. The promising results of pemigatinib and infigratinib in advanced unresectable cholangiocarcinoma harboring FGFR2 fusions or rearrangement, and erdafitinib in metastatic urothelial carcinoma with FGFR2 and FGFR3 genetic aberrations, lead to their accelerated approval by the United States (USA) FDA. Along with these agents, many phase II/III clinical trials are currently evaluating the use of derazantinib, infigratinib, and futibatinib either alone or in combination with immunotherapy. Despite the encouraging results seen with FGFR inhibitors, resistance mechanisms and side effect profile may limit their clinical utility. A better understanding of the unique FGFR-inhibitor-related toxicities would invariably help us in the prevention and effective management of FGFR-inhibitor-induced adverse events thereby enhancing their clinical benefit. Herein, we summarized the physiology of FGF/FGFR signaling and briefly discussed the possible mechanisms that could lead to FGFR inhibitor resistance and side effects. In addition, we proposed treatment guidelines for the management of FGFR-inhibitor-associated toxicities. This work would invariably help practicing oncologists to effectively manage the unique toxicities of FGFR inhibitors.

Outcomes of COVID-19 in Patients With Cancer: A Closer Look at Pre-Emptive Routine Screening Strategies.

PURPOSE: The benefit of routine pre-emptive screening for severe acute respiratory syndrome coronavirus 2 infections in patients with cancer before cancer-directed therapies is unclear. Herein, we characterize the outcomes of a cohort of patients with cancer who were diagnosed with COVID-19 by routine screening (RS) in comparison with those diagnosed on the basis of clinical suspicion or exposure history (nonroutine screening [NRS]). METHODS: A multisite prospective observational study was conducted at three major and five satellite campuses of the Mayo Clinic Cancer Center between March 18 and July 31, 2020. The primary outcome was COVID-19-related hospital admission. Secondary outcomes included intensive care unit admissions and all-cause mortality. RESULTS: Five thousand four hundred fifty-two patients underwent RS in the outpatient setting only, and 44 (0.81%) were diagnosed with COVID-19. RS detected 19 additional patients from the scheduled inpatient admissions for surgical or interventional procedures or inpatient chemotherapy. One hundred sixty-one patients were diagnosed with COVID-19 on the basis of NRS. COVID-19-related hospitalization rate (17.5% v 26.7%; P = .14), intensive care unit admission (1.6% v 5.6%; P = .19), and mortality (4.8% v 3.7%; P = .72) were not significantly different between the RS and NRS groups. In the multivariable analysis, age ≥ 60 years (odds ratio, 4.4; P = .023) and an absolute lymphocyte count ≤ 1.4 × 109/L (odds ratio, 9.2; P = .002) were independent predictors of COVID-19-related hospital admission. CONCLUSION: The COVID-19 positivity rate was low on the basis of RS. Comparing the hospital admission and mortality outcomes with the NRS cohort, there were no significant differences. The value of routine pre-emptive screening of asymptomatic patients with cancer for COVID-19 remains low.

Aspirin and Statin Use and the Risk of Gallbladder Cancer.

Aspirin and statin drugs have been associated with reduced risk of several gastrointestinal cancers, but their association with gallbladder cancer (GBC) has not been well established. We evaluated the association of aspirin and statins with the risk of GBC. Patients with GBC managed at Mayo Clinic between 2000 and 2019 were matched 1:2 with a general patient pool by age and sex. Univariable and multivariable logistic regression models were used to assess associations between GBC and aspirin or statin use. The analysis included 795 cases and 1590 controls, with a median age of 67 years. Aspirin or statin use alone or in combination was higher in controls (p < 0.001). Univariate analysis showed that the use of aspirin [odds ratio (OR): 0.11; 95%CI: 0.08-0.15] or statins (OR: 0.29; 95%CI: 0.20-0.40) and their combined use (OR: 0.18; 95%CI: 0.13-0.24) was associated with lower risk of GBC. Multivariable analysis revealed that aspirin (OR: 0.12; 95%CI: 0.09-0.16) and combined statins and aspirin (OR: 0.46; 95%CI: 0.31-0.67) were associated with lower risk of GBC. Aspirin alone or in combination with statins is associated with a strongly reduced risk of GBC. Further prospective studies are needed to confirm these results and to elucidate their mechanisms.

TAS-102: A resurrected novel Fluoropyrimidine with expanding role in the treatment of gastrointestinal malignancies.

TAS-102 is an orally administered fixed-dose formulation consisting of trifluorothymidine (TFT), a fluoropyrimidine antimetabolite, and tipiracil (TPI), an inhibitor of thymidine phosphorylase (TP) that prevents rapid degradation of TFT and ensures its bioavailability. The novelty of TAS-102 lies in its antitumor activity against 5-fluorouracil (5-FU) resistant tumors, demonstrated both in the in vitro models and xenografts. The cytotoxic activity of TFT relies primarily on extensive incorporation of the TFT metabolite into the cellular DNA inducing DNA dysfunction and cell death. In contrast, 5-fluorouracil (5-FU) interferes with DNA biosynthesis by inhibiting thymidylate synthase(TS), which partly explains the absence of cross-resistance between TAS-102 and 5-FU. TAS-102 is currently approved in the third-line setting for patients with metastatic colorectal and gastric cancer based on phase III randomized clinical trial data confirming an overall survival benefit with TAS-102. The preliminary data from recently reported studies suggest a potential expanding role of TAS-102 in a variety of gastrointestinal (GI) cancers. The current article presents an overview of the pharmacology, clinical development of TAS-102, and its emerging role in the treatment of GI cancers. In addition, we discussed the rationale underlying the ongoing clinical trials investigating various combinations of TAS-102 with other anticancer agents, including targeted therapies, in a wide range of GI tumors.

Systemic therapy for advanced hepatocellular carcinoma: targeted therapies.

Therapeutic options for advanced, unresectable hepatocellular carcinoma (HCC) have changed dramatically over the last 3 years. While surgical resection, orthotropic liver transplantation, and localized therapeutic options such as ablation, radiation therapy, and embolization remain therapeutics of choice in localized disease, systemic therapy is the only option in advanced, metastatic HCC. Since the United States Food and Drug Administration (US FDA) approval of sorafenib in 2008, targeted therapies such as sunitinib, tivantinib, brivanib, erlotinib, and linifanib; monoclonal antibody- bevacizumab showed no meaningful improvement in treatment of HCC. However, with improved understanding on the molecular pathophysiology and tumor heterogeneity of HCC, we have made progress in expanding the therapeutic options in advanced HCC. Targeted therapy with lenvatinib, cabozantinib, and regorafenib; monoclonal antibody ramucirumab; immunotherapies nivolumab and pembrolizumab have demonstrated promising results in the clinical trials. The current work outlines the molecular mechanisms and tumorigenesis of HCC, a detailed discussion of the trial results of the approved therapies in HCC, future perspectives and potential options to overcome the challenges of systemic therapy in HCC.

Prevention and treatment of FGFR inhibitor-associated toxicities.

Fibroblast growth factor receptor (FGFR) inhibitors have shown promising results in terms of objective response rates in phase I/II trials in various malignancies that harbor FGFR genetic aberrations. The class of medications brings in the concept of 'personalized' treatment by targeting susceptible FGFR genetic alterations in some rare but dismal cancers such as cholangiocarcinoma. Despite the fact that FGFR inhibitors are well-tolerated, these drugs are associated with toxicities that are distinct from that of other small-molecule tyrosine kinase inhibitors. These toxicities can result in dose reductions, interruptions, and even drug discontinuation as reported in the clinical trials. The prevention and effective management of the FGFR inhibitor-associated toxicities will allow patients to stay on these medications without the therapy interruptions. The current work is focused on summarizing the available literature on unique FGFR inhibitor-associated toxicities with a special emphasis in managing the unique adverse events.

Nephropathic Cystinosis: A Distinct Form of CKD-Mineral and Bone Disorder that Provides Novel Insights into the Regulation of FGF23.

BACKGROUND: The rare lysosomal storage disease nephropathic cystinosis presents with renal Fanconi syndrome that evolves in time to CKD. Although biochemical abnormalities in common causes of CKD-mineral and bone disorder have been defined, it is unknown if persistent phosphate wasting in nephropathic cystinosis is associated with a biochemical mineral pattern distinct from that typically observed in CKD-mineral and bone disorder. METHODS: We assessed and compared determinants of mineral homeostasis in patients with nephropathic cystinosis across the predialysis CKD spectrum to these determinants in age- and CKD stage-matched patients, with causes of CKD other than nephropathic cystinosis. RESULTS: The study included 50 patients with nephropathic cystinosis-related CDK and 97 with CKD from other causes. All major aspects of mineral homeostasis were differentially effected in patients with CKD stemming from nephropathic cystinosis versus other causes. Patients with nephropathic cystinosis had significantly lower percent tubular reabsorption of phosphate and fibroblast growth factor-23 (FGF23) at all CKD stages, and lower blood phosphate in CKD stages 3-5. Linear regression analyses demonstrated lower FGF23 levels in nephropathic cystinosis participants at all CKD stages when corrected for eGFR and age, but not when adjusted for serum phosphate. CONCLUSIONS: Nephropathic cystinosis CKD patients have mineral abnormalities that are distinct from those in CKD stemming from other causes. Persistently increased urinary phosphate excretion maintains serum phosphate levels within the normal range, thus protecting patients with nephropathic cystinosis from elevations of FGF23 during early CKD stages. These findings support the notion that phosphate is a significant driver of increased FGF23 levels in CKD and that mineral abnormalities associated with CKD are likely to vary depending on the underlying renal disease.