AimsThe MAPK pathway is constitutively activated in uveal melanoma (UM). Selumetinib (AZD6244, ARRY-142886), a MEK inhibitor, has shown limited activity as monotherapy in metastatic UM. Pre-clinical studies support synergistic cytotoxic activity for MEK inhibitors combined with taxanes, and here we sought to assess the clinical efficacy of combining selumetinib and paclitaxel.Patients and MethodsSeventy-seven patients with metastatic UM who had not received prior chemotherapy were randomised to selumetinib alone, or combined with paclitaxel with or without interruption in selumetinib two days before paclitaxel. The primary endpoint was progression free survival (PFS). After amendment, the combination arms were combined for analysis and the sample size adjusted to detect a hazard ratio (HR): 0.55, 80% power at 1-sided 5% significance level.ResultsThe median PFS in the combination arms was 4.8 months (95% CI: 3.8 - 5.6) compared with 3.4 months (2.0 - 3.9) in the selumetinib arm (HR 0.62 [90% CI 0.41 - 0.92], 1-sided p-value = 0.022). ORR was 14% and 4% in the combination and monotherapy arms respectively. Median OS was 9 months for the combination and was not significantly different from selumetinib alone (10 months) with HR of 0.98 [90% CI 0.58 - 1.66], 1-sided p-value = 0.469. Toxicity was in keeping with the known profiles of the agents involved.ConclusionsSelPac met its primary endpoint, demonstrating an improvement in PFS for combination selumetinib and paclitaxel. No improvement in OS was observed, and the modest improvement in PFS is not practice changing.

BACKGROUND:Approximately 30% of patients with pancreas cancer have unresectable locally advanced disease, which is currently treated with systemic chemotherapy. A new treatment option of irreversible electroporation (IRE) has been investigated for these patients since 2005. Cohort studies suggest that IRE confers a survival advantage, but with associated, procedure-related complications. Selection bias may account for improved survival and there have been no prospective randomised trials evaluating the harms and benefits of therapy. The aim of this trial is to evaluate the feasibility of a randomised comparison of IRE therapy with chemotherapy versus chemotherapy alone in patients with locally advanced pancreatic cancer (LAPC). METHODS AND ANALYSIS:Eligible patients with LAPC who have undergone first-line 5-FluoroUracil, Leucovorin, Irinotecan and Oxaliplatin chemotherapy will be randomised to receive either a single session of IRE followed by (if indicated) further chemotherapy or to chemotherapy alone (standard of care). Fifty patients from up to seven specialist pancreas centres in the UK will be recruited over a period of 15 months. Trial follow-up will be 12 months. The primary outcome measure is ability to recruit. Secondary objectives include practicality and technical success of treatment, acceptability of treatment to patients and clinicians and safety of treatment. A qualitative study has been incorporated to evaluate the patient and clinician perspective of the locally advanced pancreatic cancer with percutaneous irreversible electroporation trial. It is likely that the data obtained will guide the structure, the primary outcome measure, the power and the duration of a subsequent multicentre randomised controlled trial aimed at establishing the clinical efficiency of pancreas IRE therapy. Indicative procedure-related costings will be collected in this feasibility trial, which will inform the cost evaluation in the subsequent study on efficiency. ETHICS AND DISSEMINATION:The protocol has received approval by London-Brent Research Ethics Committee reference number 21/LO/0077.Results will be analysed following completion of trial recruitment and follow-up. Results will be presented to international conferences with an interest in oncology, hepatopancreaticobiliary surgery and interventional radiology and be published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER:ISRCTN14986389.

The coronavirus disease 2019 (COVID-19) pandemic has a major impact not only on public health and daily living, but also on clinical trials worldwide. To investigate the potential impact of the COVID-19 pandemic on the initiation of clinical trials, we have descriptively analyzed the longitudinal change in phase II and III interventional clinical trials initiated in Europe and in the United States. Based on the public clinical trial register EU Clinical Trials Register and clinicaltrials.gov, we conducted (i) a yearly comparison of the number of initiated trials from 2010 to 2020 and (ii) a monthly comparison from January 2020 to February 2021 of the number of initiated trials. The analyses indicate that the COVID-19 pandemic affected both the initiation of clinical trials overall and the initiation of non-COVID-19 trials. An increase in the overall numbers of clinical trials could be observed both in Europe and the United States in 2020 as compared with 2019. However, the number of non-COVID-19 trials initiated is reduced as compared with the previous decade, with a slightly larger relative decrease in the United States as compared to Europe. Additionally, the monthly trend for the initiation of non-COVID-19 trials differs between regions. In the United States, after a sharp decrease in April 2020, trial numbers reached the levels of 2019 from June 2020 onward. In Europe, the decrease was less pronounced, but trial numbers mainly remained below the 2019 average until February 2021.

Nitisinone (NTBC) was recently approved to treat alkaptonuria (AKU), but there is no information on its impact on oxidative stress and inflammation, which are observed in AKU. Therefore, serum samples collected during the clinical studies SONIA1 (40 AKU patients) and SONIA2 (138 AKU patients) were tested for Serum Amyloid A (SAA), CRP and IL-8 by ELISA; Advanced Oxidation Protein Products (AOPP) by spectrophotometry; and protein carbonyls by Western blot. Our results show that NTBC had no significant effects on the tested markers except for a slight but statistically significant effect for NTBC, but not for the combination of time and NTBC, on SAA levels in SONIA2 patients. Notably, the majority of SONIA2 patients presented with SAA > 10 mg/L, and 30 patients in the control group (43.5%) and 40 patients (58.0%) in the NTBC-treated group showed persistently elevated SAA > 10 mg/L at each visit during SONIA2. Higher serum SAA correlated with lower quality of life and higher morbidity. Despite no quantitative differences in AOPP, the preliminary analysis of protein carbonyls highlighted patterns that deserve further investigation. Overall, our results suggest that NTBC cannot control the sub-clinical inflammation due to increased SAA observed in AKU, which is also a risk factor for developing secondary amyloidosis.

Objective: Whether a Blumgart anastomosis (BA) is superior to Cattell-Warren anastomosis (CWA) in terms of postoperative pancreatic fistula (POPF) following pancreatoduodenectomy. Importance: Complications driven by POPF following pancreatic cancer resection may hinder adjuvant therapy, shortening survival. BA may reduce complications compared to CWA, improving the use of adjuvant therapy and prolonging survival. Methods: A multicenter double-blind, controlled trial of patients undergoing resection for suspected pancreatic head cancer, randomized during surgery to a BA or CWA, stratified by pancreatic consistency and duct diameter. The primary end point was POPF, and secondary outcome measures were adjuvant therapy use, specified surgical complications, quality of life, and survival from the date of randomization. For a 10% POPF reduction, 416 patients were required, 208 per arm (two-sided α = 0·05; power = 80%). Results: Z-score at planned interim analysis was 0.474 so recruitment was held to 238 patients; 236 patients were analyzed (112 BA and 124 CWA). No significant differences in POPF were observed between BA and CWA, odds ratio (95% confidence interval [CI]) 1·04 (0.58–1.88), P = 0.887, nor in serious adverse events. Adjuvant therapy was delivered to 98 (62%) of 159 eligible patients with any malignancy; statistically unrelated to arm or postoperative complications. Twelve-month overall survival, hazard ratio (95% CI), did not differ between anastomoses; BA 0.787 (0.713–0.868) and CWA 0.854 (0.792–0.921), P = 0.266, nor for the 58 patients with complications, median (IQR), 0.83 (0.74–0.91) compared to 101 patients without complications 0.82 (0.76–0.89) (P = 0.977). Conclusions: PANasta represents the most robust analysis of BA versus CWA to date.

BackgroundScreening for pancreatic ductal adenocarcinoma (PDAC) in populations at high risk is recommended. Individuals with new-onset type 2 diabetes mellitus (NOD) are the largest high-risk group for PDAC. To facilitate screening, we sought biomarkers capable of stratifying NOD subjects into those with type 2 diabetes mellitus (T2DM) and those with the less prevalent PDAC-related diabetes (PDAC-DM), a form of type 3c DM commonly misdiagnosed as T2DM.MethodsUsing mass spectrometry- and immunoassay-based methodologies in a multi-stage analysis of independent sample sets (n=443 samples), blood levels of 264 proteins were considered using Ingenuity Pathway Analysis, literature review and targeted training and validation.FindingsOf 30 candidate biomarkers evaluated in up to four independent patient sets, 12 showed statistically significant differences in levels between PDAC-DM and T2DM. The combination of adiponectin and interleukin-1 receptor antagonist (IL-1Ra) showed strong diagnostic potential, (AUC of 0.91; 95% CI: 0.84-0.99) for the distinction of T3cDM from T2DM.InterpretationAdiponectin and IL-1Ra warrant further consideration for use in screening for PDAC in individuals newly-diagnosed with T2DM.FundingNorth West Cancer Research, UK, Cancer Research UK, Pancreatic Cancer Action, UK.

INTRODUCTION:In one-third of all abdominal aortic aneurysms (AAAs), the aneurysm neck is short (juxtarenal) or shows other adverse anatomical features rendering operations more complex, hazardous and expensive. Surgical options include open surgical repair and endovascular aneurysm repair (EVAR) techniques including fenestrated EVAR, EVAR with adjuncts (chimneys/endoanchors) and off-label standard EVAR. The aim of the UK COMPlex AneurySm Study (UK-COMPASS) is to answer the research question identified by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme: 'What is the clinical and cost-effectiveness of strategies for the management of juxtarenal AAA, including fenestrated endovascular repair?'METHODS AND ANALYSIS:UK-COMPASS is a cohort study comparing clinical and cost-effectiveness of different strategies used to manage complex AAAs with stratification of physiological fitness and anatomical complexity, with statistical correction for baseline risk and indication biases. There are two data streams. First, a stream of routinely collected data from Hospital Episode Statistics and National Vascular Registry (NVR). Preoperative CT scans of all patients who underwent elective AAA repair in England between 1 November 2017 and 31 October 2019 are subjected to Corelab analysis to accurately identify and include every complex aneurysm treated. Second, a site-reported data stream regarding quality of life and treatment costs from prospectively recruited patients across England. Site recruitment also includes patients with complex aneurysms larger than 55 mm diameter in whom an operation is deferred (medical management). The primary outcome measure is perioperative all-cause mortality. Follow-up will be to a median of 5 years.ETHICS AND DISSEMINATION:The study has received full regulatory approvals from a Research Ethics Committee, the Confidentiality Advisory Group and the Health Research Authority. Data sharing agreements are in place with National Health Service Digital and the NVR. Dissemination will be via NIHR HTA reporting, peer-reviewed journals and conferences.TRIAL REGISTRATION NUMBER:ISRCTN85731188.

Purpose: To investigate the value of (18)FDG PET/CT volumetric parameters in the prediction of overall survival (OS) in patients with pancreatic cancer and also, assess their independence relative to well-established clinico-pathological variables. Methods: We conducted a retrospective analysis of patients with a confirmed diagnosis of pancreatic cancer who underwent (18)FDG PET/CT. The tumour maximum standardised uptake value (SUVmax) in addition to SUVmean, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were calculated. The prognostic value of (18)FDG PET/CT and clinico-pathological parameters for OS were assessed using univariate and multivariable analyses. Results: A sum of 89 patients were analysed in this study. Median survival for patients categorised as having high TLG (>= 55) and low TLG (<55) was 18 vs 5 months (p < 0.001). Similarly, the respective high vs low SUVmean, MTV and SUVmax were 18 vs 6 months (p = 0.001), 16 vs 6 months (p = 0.002) and 18 vs 6 months (p = 0.001). Univariate analysis showed SUVmax SUVmean, MTV, TLG, tumour size, tumour differentiation and presence of distant metastasis as prognostic factors for OS. On multivariable analysis, TLG (HR 2.0, 95% CI 1.26-3.18, p = 0.004) and the presence of distant metastasis (HR 3.37, 95% CI 1.97 -5.77, p < 0.001) emerged as independent prognostic factors. Subgroup analysis identified TLG as the only significant PET metric after adjusting for the presence of distant metastasis. Conclusions: (18)FDG PET/CT is a useful tool in the preoperative evaluation of patients with pancreatic cancer. Tumour TLG offer an independent prognostic value in both potentially operable and metastatic disease settings. (C) 2020 Elsevier Ltd, BASO - The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Abstract Background Alkaptonuria (AKU) is a disorder of tyrosine/protein metabolism leading to accumulation of homogentisic acid. Clinical management historically recommended reducing dietary protein intake, especially in childhood, which has since been discredited in the literature. For the first time, analysis of baseline cross‐sectional nutritional surveillance data from a large cohort of AKU patients is presented, which has clinical implications in all aspects of treatment planning. Method Seventy‐four patients (mean 55 years) admitted to the National Alkaptonuria Centre (NAC), underwent a global nutritional assessment, which included objective anthropometry, bioimpedance measures, habitual nutritional intake using a 7‐day food diary and key nutritional biomarkers, including 24 hours urinary nitrogen, serum albumin, total protein and total 25‐hydroxy vitamin D. All data was compared with cohort norms or recommended nutrient intakes for health (RNI). The potential beneficial impact of protein and anti‐inflammatory nutrients such as vitamin C, selenium, and zinc were statistically interrogated against the AKU severity score index (AKUSSI)—a validated measure of disease progression stratified by age. Results Fifty percent of AKU patients reported some level of protein restriction at some point in their lives. In comparison with national data sets, AKU patients present with significantly lower than predicted mid‐upper arm circumference, grip strength, BMI, total energy and protein intake, and higher than predicted percentage body fat. They therefore meet the ESPEN criteria as “clinically undernourished.” Severity fluctuates over the life course. No statistical association is identified between protein intake, expressed as %RNI or g/kg, or anti‐inflammatory nutrients, including vitamin C as a high dose supplement on the severity of the disease, when correlated against the validated AKUSSI score. Conclusion AKU patients are at risk of protein depletion associated with a “perfect storm” of risk factors: historical, poorly evidenced recommendations to reduce total protein intake; limited mobility as the condition progresses, compromising muscle integrity; frequent hospital admissions for major surgery associated with multiple joint replacements, creating pinch points of high metabolic demand and the potential impact of the disease itself. As this is the first time this risk has been identified, the authors consider the dietetic implications of nitisinone treatment, which requires dietary protein control to manage the acquired tyrosinaemia. The lack of statistically significant evidence to support dietary manipulation of any kind to impede disease progression in AKU is demonstrated.

Worldwide, >60% patients with rheumatoid arthritis (RA) are overweight/obese (body mass index, BMI≥25kg/m2). Studies demonstrate poorer disease outcomes and health-related quality of life in these patients. However, little is known about the effect of increased BMI on drug choice, dosing, or treatment response. Objective: To explore the effect of increased BMI on DMARD-prescribing, methotrexate (MTX)-dose, and disease activity over 12 months. Participants registered on METEOR (international database of RA patients) were stratified into early (<1year post-diagnosis, eRA), and established RA (estRA). EULAR response and DAS28 remission (including components), and treatment regimens were recorded at baseline, 6, and 12 months. Increased BMI (defined overweight and obese) were explored in 1) eRA and 2) estRA, as predictors of good EULAR response, DAS28 remission, number of DMARDs prescribed, and MTX-dose. Logistic and linear regression models (controlling for age, gender, smoking, and baseline outcome values), subgroup analyses (by drug exposure), and sensitivity analyses, were performed. 1,313 patients (1056 female) were included, 582 eRA. In eRA, increased BMI was not significantly associated with remission outcomes. In estRA, obese patients on monotherapy were statistically significantly less likely to achieve good EULAR response [OR 0.4 (95%CI 0.23-0.7)] or DAS28 remission [OR 0.47 (95%CI 0.24-0.88)] at 6 months, compared to those of normal weight. A similar trend observed at 12 months did not reach significance. Obese estRA patients were more likely to be treated with combination conventional synthetic DMARDs (csDMARD) than monotherapy, compared with those of normal weight, significant at 6 months [OR 1.59 (95%CI 1.03-2.45)]. In early and established disease, no significant difference in remission outcomes was demonstrated for combination compared to monotherapy. However, overweight/obese individuals were less likely to achieve remission overall (non-significant). Regarding components of remission, tender joint count and ESR in estRA were higher in overweight/obese individuals at 6 months [β 1.05 (95%CI 0.05-2.06)] and 12 months [β 6.58 (95%CI 0.16-12.99)] respectively, compared to those of normal weight. Sensitivity analyses showed no difference in the above results. MTX-dose was available for 613 patients at sequential visits. Within this subgroup, overweight/obese patients with both eRA and estRA were exposed to higher doses of MTX (mono- and combination-therapy) at any time-point, compared to those of normal weight. eRA: overweight: β 5.33, 95%CI 3.10-7.56; obese: β 6.01, 95%CI 3.57-8.46. estRA: overweight: β 4.87, 95%CI 3.79-5.95; obese: β 2.69, 95%CI 1.56-3.83. An average weekly dose of 20mg was prescribed in overweight/obese patients, compared to 15mg in those of normal weight. We observed that overweight/obese individuals require more intense csDMARD therapy to achieve the same treatment targets as those of normal weight. Awareness of this is particularly important given the increasing obesity prevalence in RA. M. Dey None. S.S. Zhao None. E. Psarelli None. R.J. Moots None. R. Landewe Other; Member of METEOR board. N.J. Goodson None.

For over two decades, nitisinone (NTBC) has been successfully used to manipulate the tyrosine degradation pathway and save the lives of many children with hereditary tyrosinaemia type 1. More recently, NTBC has been used to halt homogentisic acid accumulation in alkaptonuria (AKU) with evidence suggesting its efficacy as a disease modifying agent. NTBC-induced hypertyrosinaemia has been associated with cognitive impairment and potentially sight-threatening keratopathy. In the context of a non-lethal condition (ie, AKU), these serious risks call for an evaluation of the wider impact of NTBC on the tyrosine pathway. We hypothesised that NTBC increases the tyrosine pool size and concentrations in tissues. In AKU mice tyrosine concentrations of tissue homogenates were measured before and after treatment with NTBC. In humans, pulse injection withl-[C-13(9)]tyrosine andl-[d(8)]phenylalanine was used along with compartmental modelling to estimate the size of tyrosine pools before and after treatment with NTBC. We found that NTBC increased tyrosine concentrations in murine tissues by five to nine folds. It also significantly increased the tyrosine pool size in humans (P < .001), suggesting that NTBC increases tyrosine not just in serum but also in tissues (ie, acquired tyrosinosis). This study provides, for the first time, the experimental proof for the magnitude of NTBC-related acquired tyrosinosis which should be overcome to ensure the safe use of NTBC in AKU.

Background Alkaptonuria is a rare, genetic, multisystem disease characterised by the accumulation of homogentisic acid (HGA). No HGA-lowering therapy has been approved to date. The aim of SONIA 2 was to investigate the efficacy and safety of once-daily nitisinone for reducing HGA excretion in patients with alkaptonuria and to evaluate whether nitisinone has a clinical benefit. Methods SONIA 2 was a 4-year, open-label, evaluator-blind, randomised, no treatment controlled, parallel-group study done at three sites in the UK, France, and Slovakia. Patients aged 25 years or older with confirmed alkaptonuria and any clinical disease manifestations were randomly assigned (1:1) to receive either oral nitisinone 10 mg daily or no treatment. Patients could not be masked to treatment due to colour changes in the urine, but the study was evaluator-blinded as far as possible. The primary endpoint was daily urinary HGA excretion (u-HGA(24)) after 12 months. Clinical evaluation Alkaptonuria Severity Score Index (cAKUSSI) score was assessed at 12, 24, 36, and 48 months. Efficacy variables were analysed in all randomly assigned patients with a valid u-HGA 24 measurement at baseline. Safety variables were analysed in all randomly assigned patients. The study was registered at ClinicalTrials.gov (NCT01916382). Findings Between May 7, 2014, and Feb 16, 2015, 139 patients were screened, of whom 138 were included in the study, with 69 patients randomly assigned to each group. 55 patients in the nitisinone group and 53 in the control group completed the study. u-HGA 24 at 12 months was significantly decreased by 99.7% in the nitisinone group compared with the control group (adjusted geometric mean ratio of nitisinone/control 0.003 [95% CI 0.003 to 0.004], p<0.0001). At 48 months, the increase in cAKUSSI score from baseline was significantly lower in the nitisinone group compared with the control group (adjusted mean difference -8.6 points [-16.0 to -1.2], p=0.023). 400 adverse events occurred in 59 (86%) patients in the nitisinone group and 284 events occurred in 57 (83%) patients in the control group. No treatment-related deaths occurred. Interpretation Nitisinone 10 mg daily was well tolerated and effective in reducing urinary excretion of HGA. Nitisinone decreased ochronosis and improved clinical signs, indicating a slower disease progression.

ESPAC-4 : A Multicenter, International, Randomized Controlled Phase III Trial of Adjuvant Combination Chemotherapy of Gemcitabine (GEM) and Capecitabine (CAP), Versus Monotherapy Gemcitabine in Patients With Resected Pancreatic Ductal Adenocarcinoma

ImportanceThe patterns of disease recurrence after resection of pancreatic ductal adenocarcinoma with adjuvant chemotherapy remain unclear.ObjectiveTo define patterns of recurrence after adjuvant chemotherapy and the association with survival.Design, Setting, and ParticipantsProspectively collected data from the phase 3 European Study Group for Pancreatic Cancer 4 adjuvant clinical trial, an international multicenter study. The study included 730 patients who had resection and adjuvant chemotherapy for pancreatic cancer. Data were analyzed between July 2017 and May 2019.InterventionsRandomization to adjuvant gemcitabine or gemcitabine plus capecitabine.Main Outcomes and MeasuresOverall survival, recurrence, and sites of recurrence.ResultsOf the 730 patients, median age was 65 years (range 37-81 years), 414 were men (57%), and 316 were women (43%). The median follow-up time from randomization was 43.2 months (95% CI, 39.7-45.5 months), with overall survival from time of surgery of 27.9 months (95% CI, 24.8-29.9 months) with gemcitabine and 30.2 months (95% CI, 25.8-33.5 months) with the combination (HR, 0.81; 95% CI, 0.68-0.98; P = .03). The 5-year survival estimates were 17.1% (95% CI, 11.6%-23.5%) and 28.0% (22.0%-34.3%), respectively. Recurrence occurred in 479 patients (65.6%); another 78 patients (10.7%) died without recurrence. Local recurrence occurred at a median of 11.63 months (95% CI, 10.05-12.19 months), significantly different from those with distant recurrence with a median of 9.49 months (95% CI, 8.44-10.71 months) (HR, 1.21; 95% CI, 1.01-1.45; P = .04). Following recurrence, the median survival was 9.36 months (95% CI, 8.08-10.48 months) for local recurrence and 8.94 months (95% CI, 7.82-11.17 months) with distant recurrence (HR, 0.89; 95% CI, 0.73-1.09; P = .27). The median overall survival of patients with distant-only recurrence (23.03 months; 95% CI, 19.55-25.85 months) or local with distant recurrence (23.82 months; 95% CI, 17.48-28.32 months) was not significantly different from those with only local recurrence (24.83 months; 95% CI, 22.96-27.63 months) (P = .85 and P = .35, respectively). Gemcitabine plus capecitabine had a 21% reduction of death following recurrence compared with monotherapy (HR, 0.79; 95% CI, 0.64-0.98; P = .03).Conclusions and RelevanceThere were no significant differences between the time to recurrence and subsequent and overall survival between local and distant recurrence. Pancreatic cancer behaves as a systemic disease requiring effective systemic therapy after resection.Trial RegistrationClinicaltrials.gov Identifier: NCT00058201, EudraCT 2007-004299-38, and ISRCTN 96397434.

The clinical effects of alkaptonuria (AKU) are delayed and ageing influences disease progression. Morbidity of AKU is secondary to high circulating homogentisic acid (HGA) and ochronosis. It is not known whether HGA is produced by or processed in the kidney in AKU. Data from AKU patients from four studies were merged to form a single AKU group. A control group of non-AKU subjects was generated by merging data from two non-AKU studies. Data were used to derive renal clearance and fractional excretion (FE) ratios for creatinine, HGA, phenylalanine (PHE) and tyrosine (TYR) using standard calculations, for comparison between the AKU and the control groups. There were 225 AKU patients in the AKU group and 52 in the non-AKU control group. Circulating HGA increased with age (P < 0.001), and was significantly associated with decreased HGA clearance (CLHGA) (P < 0.001) and FEHGA(P < 0.001). CL(HGA)and FE(HGA)were increased beyond the theoretical maximum renal plasma flow, confirming renal production and emphasising the greater contribution of net tubular secretion than glomerular filtration to renal elimination of HGA. The kidneys are crucial to elimination of HGA. Elimination of HGA is impaired with age resulting in worsening disease over time. The kidney is an important site for production of HGA. Tubular secretion of HGA contributes more to elimination of HGA in AKU than glomerular filtration.

Nitisinone decreases homogentisic acid (HGA) in Alkaptonuria (AKU) by inhibiting the tyrosine metabolic pathway in humans. The effect of different daily doses of nitisinone on circulating and 24 h urinary excretion of phenylalanine (PA), tyrosine (TYR), hydroxyphenylpyruvate (HPPA), hydroxyphenyllactate (HPLA) and HGA in patients with AKU was studied over a four week period. Forty AKU patients, randomised into five groups of eight patients, received doses of 1, 2, 4 or 8 mg of nitisinone daily, or no drug (control). Metabolites were analysed by tandem mass spectrometry in 24 h urine and serum samples collected before and after nitisinone. Serum metabolites were corrected for total body water and the sum of 24 hr urine plus total body water metabolites of PA, TYR, HPPA, HPLA and HGA were determined. Body weight and urine urea were used to check on stability of diet and metabolism over the 4 weeks of study. The sum of quantities of urine metabolites (PA, TYR, HPPA, HPLA and HGA) were similar pre- and post-nitisinone. The sum of total body water metabolites were significantly higher post-nitisinone (p < 0.0001) at all doses. Similarly, combined 24 hr urine:total body water ratios for all analytes were significantly higher post-nitisinone, compared with pre-nitisinone baseline for all doses (p = 0.0002 – p < 0.0001). Significantly higher concentrations of metabolites from the tyrosine metabolic pathway were observed in a dose dependant manner following treatment with nitisinone and we speculate that, for the first time, experimental evidence of the metabolite pool that would otherwise be directed towards pigment formation, has been unmasked.