ATN-224 Research Articles

Effects of tetrathiomolybdate on copper metabolism in healthy volunteers and in patients with Wilson disease

In Wilson disease (WD), copper accumulates in the liver and brain causing disease. Bis-choline tetrathiomolybdate (TTM) is a potent copper chelator that may be associated with a lower risk of inducing paradoxical neurological worsening than conventional therapy for neurologic WD. To better understand the mode of action of TTM, we investigated its effects on copper absorption and biliary excretion. In a double-blind randomized setting, hepatic 64Cu activity was examined after orally administered 64Cu by PET/CT in 16 healthy volunteers before and after seven days of TTM treatment (15mg/d) or placebo. Oral 64Cu was administered one hour after the final TTM dose. Changes in hepatic 64Cu activity reflected changes in intestinal 64Cu uptake. Additionally, in four patients with WD, the distribution of 64Cu in venous blood, liver, gallbladder, kidney, and brain was followed after i.v. 64Cu dosing for up to 68 hours before and after seven days of TTM (15mg/day), using PET/MRI. Increased gallbladder 64Cu activity was taken as evidence of increased biliary 64Cu excretion. In healthy volunteers, TTM reduced intestinal 64Cu uptake by 82% 15 hours after the oral 64Cu dose. In patients with WD, gallbladder 64Cu activity was negligible before and after TTM, while TTM effectively retained 64Cu in the blood, significantly reduced hepatic 64Cu activity at all time-points and significantly reduced cerebral 64Cu activity two hours after the intravenous 64Cu dose. While we did not show an increase in biliary excretion of 64Cu following TTM administration, we demonstrated that TTM effectively inhibited most intestinal 64Cu uptake and retained 64Cu in the blood stream, limiting the exposure of organs like the liver and brain to 64Cu. Bis-choline tetrathiomolybdate (TTM) is an investigational copper chelator being developed for the treatment of Wilson disease. In animal models of Wilson disease, TTM has been shown to facilitate biliary copper excretion. In the present human study, TTM surprisingly did not facilitate biliary copper excretion but instead reduced intestinal copper uptake to a clinically significant degree. Our study builds on our understanding of human copper metabolism and the mechanism of action of TTM.

Monitoring of Copper in Wilson Disease.

(1) Introduction: Wilson's disease (WND) is an autosomal recessive disorder of copper (Cu) metabolism. Many tools are available to diagnose and monitor the clinical course of WND. Laboratory tests to determine disorders of Cu metabolism are of significant diagnostic importance. (2) Methods: A systematic review of the literature in the PubMed, Science Direct, and Wiley Online Library databases was conducted. (Results): For many years, Cu metabolism in WND was assessed with serum ceruloplasmin (CP) concentration, radioactive Cu test, total serum Cu concentration, urinary copper excretion, and Cu content in the liver. The results of these studies are not always unambiguous and easy to interpret. New methods have been developed to calculate non-CP Cu (NCC) directly. New parameters, such as relative Cu exchange (REC), reflecting the ratio of CuEXC to total serum Cu, as well as relative Cu exchange (REC), reflecting the ratio of CuEXC to total serum Cu, have been shown to be an accurate tool for the diagnosis of WND. Recently, a direct and fast LC-ICP-MS method for the study of CuEXC was presented. A new method to assess Cu metabolism during treatment with ALXN1840 (bis-choline tetrathiomolybdate [TTM]) has been developed. The assay enables the bioanalysis of CP and different types of Cu, including CP-Cu, direct NCC (dNCC), and labile bound copper (LBC) in human plasma. Conclusions: A few diagnostic and monitoring tools are available for patients with WND. While many patients are diagnosed and adequately assessed with currently available methods, diagnosis and monitoring is a real challenge in a group of patients who are stuck with borderline results, ambiguous genetic findings, and unclear clinical phenotypes. Technological progress and the characterization of new diagnostic parameters, including those related to Cu metabolism, may provide confidence in the more accurate diagnosis of WND in the future.

Accumulation of molybdenum in major organs following repeated oral administration of bis-choline tetrathiomolybdate in the Sprague Dawley rat.

Molybdenum is an essential dietary trace element required for several critical enzyme systems. High intake is associated with toxicity in ruminants and animal studies. The proposed therapeutic use of molybdenum-based drugs poses a potential risk for accumulation through chronic administration of therapeutic doses of this element. The current experiment was designed to study the effect of daily dosing of a molybdenum compound, bis-choline tetrathiomolybdate (TTM), in Sprague Dawley rats using laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-ToF-MS) and two dosing levels of TTM for up to 3months. To investigate if molybdenum accumulation was associated with tissue toxicity, histopathology, haematology and clinical biochemistry markers of toxicity were incorporated into the study design. There were no behavioural signs of toxicity to the rats, and no clinical or anatomic pathology was associated with treatment. The current data did show a progressive accumulation of molybdenum within the adrenal gland, kidneys, liver, spleen, brain and testes. Although this was not associated with tissue toxicity within the 3-month study design, greater exposure over a longer period of time has the potential for producing adverse pathophysiological cellular function. Tissue toxicity, as a result of local excessive accumulation of molybdenum over time, has clear implications for the therapeutic use of molybdenum in humans and demands sensitive monitoring of tissue molybdenum levels to avoid toxicity. The current study highlights the shortcomings of conventional biomonitoring approaches to detect molybdenum accumulation with the goal of avoiding molybdenum-associated toxicity.

Diagnosis of Liver Cirrhosis on the Background of Mutations H63D of the HFE Gene and H1069Q of the ATP7B Gene in associated with Hemochromatosis and Wilson's Disease (Clinical Case)

The purpose of the study was to ilustrate the analysis of etiological factors of liver cirrhosis using clinical and anamnestic data and the results of instrumental, laboratory and genetic researches. Materials and methods. The data of anamnesis and objective examination, results of instrumental, laboratory and genetic research methods are evaluated and analyzed. Modern protocols and medical literature were used. Results and discussion. Clinical case of the patient, 52 years old. Complaints of weakness, pain in the left hypochondrium, taste of iron, convulsions of the upper and lower extremities. Laboratory and instrumental methods of research allowed to establish the following indicators in the patient: erythrocytopenia, thrombocytopenia, neutropenia, persistent lymphocytosis, lecopenia, decreased platelet count, increased average erythrocyte volume and average hemoglobin content in one erythromycin distribution, albuminemia, increased beta globulin, decreased albumin to globulin ratio, increased liver enzymes (ALT, AST, bilirubin direct) and GGT, blood iron metabolism (COPD and iron levels), iron saturation and iron ferritin saturation, negative immunological analysis for antinuclear antibodies (ANA), HbS Ag and anti-HCV were not detected. The patient was consulted by a hematologist, lymphoproliferative diseases were excluded. On the basis of data on hepatosplenomegaly, portal hypertension, varicose veins of the esophagus, lymphadenopathy, excluding nonalcoholic fatty liver disease, alcoholic fatty liver disease, viral hepatitis, autoimmune hepatitis, biliary cirrhosis, diagnosed with a diagnosis on the detection of mutations that cause hemochromatosis and Wilson's disease. Molecular genetic studies have shown the following results: the H63D mutation of the HFE gene in the heterozygous state and the H1069Q mutation of the ATP7B gene in the heterozygous state were detected. Mutation testing and phenotype prediction based on genotype opens up prospects not only for personalized therapy, but also for the development of new treatment strategies. The literature provides data about new therapies with different mechanisms of action and discusses studies on Bis-choline tetrathiomolybdate in patients, pre-clinical studies of a novel chelator methanobactin and animal studies exploring cures for WD with gene therapy using adeno-associated vectors that introduce ATP7B into liver cells. Conclusion. The clinical case showed the need to involve specialists in various specialties and a set of research methods to establish the etiology of liver cirrhosis and further etiopathogenetic treatment and the formation of risk groups for primary prevention among relatives

FRI277 - Accumulation of molybdenum in major organs following chronic oral administration of bis-choline tetrathiomolybdate in Sprague Dawley rats

FRI277 - Accumulation of molybdenum in major organs following chronic oral administration of bis-choline tetrathiomolybdate in Sprague Dawley rats

Bis-choline tetrathiomolybdate prevents copper-induced blood-brain barrier damage.

In Wilson disease, excessive copper accumulates in patients' livers and may, upon serum leakage, severely affect the brain according to current viewpoints. Present remedies aim at avoiding copper toxicity by chelation, for example, by D-penicillamine (DPA) or bis-choline tetrathiomolybdate (ALXN1840), the latter with a very high copper affinity. Hence, ALXN1840 may potentially avoid neurological deterioration that frequently occurs upon DPA treatment. As the etiology of such worsening is unclear, we reasoned that copper loosely bound to albumin, that is, mimicking a potential liver copper leakage into blood, may damage cells that constitute the blood-brain barrier, which was found to be the case in an in vitro model using primary porcine brain capillary endothelial cells. Such blood-brain barrier damage was avoided by ALXN1840, plausibly due to firm protein embedding of the chelator bound copper, but not by DPA. Mitochondrial protection was observed, a prerequisite for blood-brain barrier integrity. Thus, high-affinity copper chelators may minimize such deterioration in the treatment of neurologic Wilson disease.

Recent advances in Wilson disease.

Wilson disease (WD) is rare genetic disorder that presents with varied phenotype that can at times make the diagnosis challenging. Medical treatments are available, but there are still unmet needs for patients. Since life-long therapy is necessary, adherence to medical therapy and best practices for monitoring and individualizing therapy continue to evolve. Studies are ongoing that address some of these issues. In the current review we focused our attention to recent advances in the diagnosis of WD, current medical treatments, future potential therapies and treatment monitoring. We include discussion of new methodology for detection and quantitation of ophthalmologic signs of WD, new brain imaging modalities for early detection of neurologic involvement in patients and potential new diagnostic methodology using blood samples that may be applicable to newborn screening and adult disease diagnosis. In addition, there are new strategies aimed at improving adherence and outcomes with currently available therapies, including once daily chelation dosing and discussion of the efficacy of different zinc salt compounds. With respect to new therapies with different mechanisms of action, we discuss studies on Bis-choline tetrathiomolybdate (TTM) in patients, pre-clinical studies of a novel chelator methanobactin and other animal studies exploring cures for WD with gene therapy using adeno-associated vectors (AAVs) that introduce ATP7B into liver cells. There are also promising advances in the more accurate measurement of non-ceruloplasmin bound copper and exchangeable copper in the circulation which would potentially help with monitoring and individualization of treatment and possibly play a role in future disease diagnosis.

Recent advances in Wilson disease

Wilson disease (WD) is rare genetic disorder that presents with varied phenotype that can at times make the diagnosis challenging. Medical treatments are available, but there are still unmet needs for patients. Since life-long therapy is necessary, adherence to medical therapy and best practices for monitoring and individualizing therapy continue to evolve. Studies are ongoing that address some of these issues. In the current review we focused our attention to recent advances in the diagnosis of WD, current medical treatments, future potential therapies and treatment monitoring. We include discussion of new methodology for detection and quantitation of ophthalmologic signs of WD, new brain imaging modalities for early detection of neurologic involvement in patients and potential new diagnostic methodology using blood samples that may be applicable to newborn screening and adult disease diagnosis. In addition, there are new strategies aimed at improving adherence and outcomes with currently available therapies, including once daily chelation dosing and discussion of the efficacy of different zinc salt compounds. With respect to new therapies with different mechanisms of action, we discuss studies on Bis-choline tetrathiomolybdate (TTM) in patients, pre-clinical studies of a novel chelator methanobactin and other animal studies exploring cures for WD with gene therapy using adeno-associated vectors (AAVs) that introduce ATP7B into liver cells. There are also promising advances in the more accurate measurement of non-ceruloplasmin bound copper and exchangeable copper in the circulation which would potentially help with monitoring and individualization of treatment and possibly play a role in future disease diagnosis.

Laser Ablation Inductively Coupled Plasma Spectrometry: Metal Imaging in Experimental and Clinical Wilson Disease

Wilson disease is an inherited disorder caused by mutations in the ATP7B gene resulting in copper metabolism disturbances. As a consequence, copper accumulates in different organs with most common presentation in liver and brain. Chelating agents that nonspecifically chelate copper, and promote its urinary excretion, or zinc salts interfering with the absorption of copper from the gastrointestinal tract, are current medications. Also gene therapy, restoring ATP7B gene function or trials with bis-choline tetrathiomolybdate (WTX101) removing excess copper from intracellular hepatic copper stores and increasing biliary copper excretion, is promising in reducing body’s copper content. Therapy efficacy is mostly evaluated by testing for evidence of liver disease and neurological symptoms, hepatic synthetic functions, indices of copper metabolisms, urinary copper excretions, or direct copper measurements. However, several studies conducted in patients or Wilson disease models have shown that not only the absolute concentration of copper, but also its spatial distribution within the diseased tissue is relevant for disease severity and outcome. Here we discuss laser ablation inductively coupled plasma spectrometry imaging as a novel method for accurate determination of trace element concentrations with high diagnostic sensitivity, spatial resolution, specificity, and quantification ability in experimental and clinical Wilson disease specimens.

Orphan designation: Choline tetrathiomolybdate, Treatment of Wilson's disease

Orphan designation: Choline tetrathiomolybdate, Treatment of Wilson's disease

Orphan designation: Choline tetrathiomolybdate, Treatment of Wilson's disease

Orphan designation: Choline tetrathiomolybdate, Treatment of Wilson's disease

Bis-choline Tetrathiomolybdate as Old Drug in a New Design for Wilson's Disease: Good for Brain and Liver?

Bis-choline Tetrathiomolybdate as Old Drug in a New Design for Wilson's Disease: Good for Brain and Liver?

WTX101 – an investigational drug for the treatment of Wilson disease

ABSTRACTIntroduction: Wilson disease (WD) is a genetic disorder in which excess toxic copper accumulates in the liver, brain, and other tissues leading to severe and life-threatening symptoms. Copper overload can be assessed as non-ceruloplasmin-bound copper non-ceruloplasmin-bound copper (NCC) in blood. Current therapies are limited by efficacy, safety concerns, and multiple-daily dosing.Areas covered: This article reviews the literature on WTX101 (bis-choline tetrathiomolybdate), an oral first-in-class copper–protein-binding agent in development for the treatment of WD.Expert opinion: In a proof-of-concept phase II trial, once-daily WTX101 over 24 weeks rapidly lowered NCC levels and this was accompanied by improved neurological status without apparent initial drug-induced paradoxical worsening, reduced disability, stable liver function, with a favorable safety profile. WTX101 directly removes excess copper from intracellular hepatic copper stores and also forms an inert tripartite complex with copper and albumin in the circulation and promotes biliary copper excretion. These mechanisms may explain the rapid biochemical and clinical improvements observed. A phase III trial of WTX101 is ongoing and results are eagerly awaited to confirm if WTX101 can improve the treatment of this devastating disease.

Metabolic disposition of WTX101 (bis-choline tetrathiomolybdate) in a rat model of Wilson disease

1. WTX101 (bis-choline tetrathiomolybdate) is an investigational copper (Cu)-protein-binding agent developed for the treatment of Wilson disease (WD), a rare genetic disorder caused by mutations in the ATP7B Cu-transporter and resulting in toxic Cu accumulation.2. Mass balance of a single intravenous WTX101 dose, measured as molybdenum (Mo), was assessed over 168 h in control (Long Evans Agouti [LEA]) and Long-Evans Cinnamon (LEC) rats, a WD model.3. In LEC rats, Mo was partially excreted (up to 45%); 29% by renal clearance, and faecal clearance, still ongoing at 168 h, accounted for 16%. In contrast, in LEA rats, Mo was almost fully excreted (∼87%); 79% was renally cleared with only 7% faecal excretion.4. In LEC rats, the proportion of faecal to renal Mo excretion was enhanced (4:6) compared to controls (1:9).5. Substantially more Mo was found in LEC liver and kidney compared with LEA tissues, in line with tissue Cu distribution.6. These findings are consistent with the WTX101 mechanism of action: in the WD model, excess Cu is removed from hepatic metallothionein and retained within the stable tetrathiomolybdate-Cu-albumin tripartite complex, preventing tetrathiomolybdate degradation and resulting in less urinary elimination and greater faecal excretion than in controls.

Bis-choline tetrathiomolybdate in patients with Wilson's disease: an open-label, multicentre, phase 2 study

Wilson's disease is a genetic disorder in which copper accumulates in the liver, brain, and other tissues. Therapies are limited by efficacy, safety concerns, and multiple daily dosing. Bis-choline tetrathiomolybdate (WTX101) is an oral first-in-class copper-protein-binding molecule that targets hepatic intracellular copper and reduces plasma non-ceruloplasmin-bound copper (NCC) by forming tripartite complexes with albumin and increasing biliary copper excretion. We aimed to assess the efficacy and safety of WTX101 in the initial or early treatment of patients with Wilson's disease. We did this open-label, phase 2 study at 11 hospitals in the USA and Europe. We enrolled patients (≥18 years) with Wilson's disease who were untreated or had received no more than 24 months of treatment with chelators or zinc, had a Leipzig score of 4 or more, and had NCC concentrations above the lower limit of the normal reference range (≥0·8 μmol/L). Eligible patients received WTX101 monotherapy at a starting dose of 15-60 mg/day on the basis of baseline NCC concentrations for the first 4-8 weeks, with response-guided individualised dosing for the remaining weeks up to week 24. Investigators, other hospital personnel, and patients were aware of the identity of the treatment. The primary endpoint was change in baseline NCC concentrations corrected for copper in tetrathiomolybdate-copper-albumin complexes (NCCcorrected) at 24 weeks, with treatment success defined as achievement or maintenance of normalised NCCcorrected (≤2·3 μmol/L [upper limit of normal]) or achievement of at least a 25% reduction in NCCcorrected from baseline at 24 weeks. This study is registered with ClinicalTrials.gov, number NCT02273596. Between Nov 24, 2014, and April 27, 2016, 28 patients were enrolled and received WTX101; 22 (79%) patients completed the study up to week 24. At 24 weeks, 20 (71%, 95% CI 51·3-86·8; p<0·0001) of 28 patients met the criteria for treatment success: 16 (57%) treated with WTX101 either achieved or maintained normalised NCCcorrected concentrations and 4 (14%) had at least a 25% reduction from baseline NCCcorrected. Mean NCCcorrected was reduced by 72% from baseline to week 24 (least squares mean difference -2·4 μmol/L [SE 0·4], 95% CI -3·2 to -1·6; p<0·0001). No cases of paradoxical drug-related neurological worsening were recorded. Liver function was stable in all patients, although reversible increased concentrations of asymptomatic alanine or aspartate aminotransferase, or γ-glutamyltransferase, without increased bilirubin, occurred in 11 (39%) of 28 patients who received at least 30 mg/day. 11 serious adverse events were reported in seven (25%) patients and included psychiatric disorders (six events in four patients), gait disturbance (one event), elevated liver aminotransferases (two events in two patients, one with agranulocytosis), and decline in neurological functioning (one event, likely due to natural disease progression although causality could not be ruled out). The seven serious adverse events categorised as psychiatric disorders and as gait disturbance were assessed as unlikely to be related to the study drug, whereas the remaining four events were possibly or probably related. Our findings indicate that WTX101 might be a promising new therapeutic approach for Wilson's disease, with a unique mode of action. In view of its once-daily dose and favourable safety profile, WTX101 could improve the treatment of patients with this debilitating condition. Wilson Therapeutics AB.

Bis-choline tetrathiomolybdate for Wilson's disease

Bis-choline tetrathiomolybdate for Wilson's disease

The copper chelator ATN-224 induces peroxynitrite-dependent cell death in hematological malignancies

Chemoresistance due to oxidative stress resistance or upregulation of Bcl-2 contributes to poor outcome in the treatment of hematological malignancies. In this study, we utilize the copper-chelator drug ATN-224 (choline tetrathiomolybdate) to induce cell death in oxidative stress-resistant cells and cells overexpressing Bcl-2 by modulating the cellular redox environment and causing mitochondrial dysfunction. ATN-224 treatment decreases superoxide dismutase 1 (SOD1) activity, increases intracellular oxidants, and induces peroxynitrite-dependent cell death. ATN-224 also targets the mitochondria, decreasing both cytochrome c oxidase (CcOX) activity and mitochondrial membrane potential. The concentration of ATN-224 required to induce cell death is proportional to SOD1 levels, but independent of Bcl-2 status. In combination with doxorubicin, ATN-224 enhances cell death. In primary B-cell acute lymphoblastic leukemia patient samples, ATN-224 decreases the viable cell number. Our findings suggest that ATN-224’s dual targeting of SOD1 and CcOX is a promising approach for treatment of hematological malignancies either as an adjuvant or as a single agent.

A non-comparative randomized phase II study of 2 doses of ATN-224, a copper/zinc superoxide dismutase inhibitor, in patients with biochemically recurrent hormone-naïve prostate cancer

ObjectiveATN-224 (choline tetrathiomolybdate) is an oral Cu2+/Zn2+-superoxide dismutase 1 (SOD1) inhibitor with preclinical antitumor activity. We hypothesized that ATN-224 may induce antitumor effects as an antiangiogenic agent at low dose-levels while possessing direct antitumor activity at higher dose-levels. The objective of this study was to screen its clinical activity in patients with biochemically recurrent hormone-naïve prostate cancer. MethodsBiochemically-recurrent prostate cancer patients with prostate specific antigen doubling times (PSADT) < 12 months, no radiographic evidence of metastasis, and no hormonal therapy within 6 months (with serum testosterone levels > 150 ng/dl) were eligible. ATN-224 was administered at 2 dose-levels, 300 mg (n = 23) or 30 mg (n = 24) daily, by way of randomization. PSA progression was defined as a ≥50% increase (and >5 ng/ml) in PSA from baseline or post-treatment nadir. Endpoints included the proportion of patients who were free of PSA progression at 24 weeks, changes in PSA slope/PSADT, and safety. The study was not powered to detect differences between the 2 treatment groups. ResultsAt 24 weeks, 59% (95% CI 33%–82%) of men in the low-dose arm and 45% (95% CI 17%–77%) in the high-dose arm were PSA progression-free. Median PSA progression-free survival was 30 weeks (95% CI 21–40+) and 26 weeks (95% CI 24–39+) in the low-dose and high-dose groups, respectively. Pre- and on-treatment PSA kinetics analyses showed a significant mean PSA slope decrease (P = 0.006) and a significant mean PSADT increase (P = 0.032) in the low-dose arm only. Serum ceruloplasmin levels, a biomarker for ATN-224 activity, were lowered in the high-dose group, but did not correlate with PSA changes. ConclusionsLow-dose ATN-224 (30 mg daily) may have biologic activity in men with biochemically-recurrent prostate cancer, as suggested by an improvement in PSA kinetics. However, the clinical significance of PSA kinetics changes in this patient population remains uncertain. The absence of a dose-response effect also reduces enthusiasm, and there are currently no plans to further develop this agent in prostate cancer.

A randomized, phase II study of ATN-224 in patients with biochemically relapsed, hormone-naive prostate cancer: A DOD/PCF Prostate Cancer Clinical Trials Consortium trial

5135 Background: ATN-224 (choline tetrathiomolybdate) is an orally active, small molecule that has antiangiogenic and antitumor effects in prostate cancer (PCa) models. ATN-224 targets Cu2+/Zn2+superoxide dismutase 1 (SOD1) and suppress the generation of H2O2 leading to activation of a number of phosphatases, a group of negative growth regulatory enzymes. We hypothesized that ATN-224 may induce antitumor effect as an antiangiogenic (at 30 mg dose level) and possesses direct antitumor activity at higher dose (300 mg/day). Methods: PCa pts with PSA doubling time (PSADT) of &lt; 12 months, no radiographic evidence of metastasis, no hormonal therapy within 6 months were enrolled. All pts had testosterone &gt; 150 ng/dL at baseline. ATN-224 was administered at 2 dose levels. PSA progression was defined as at least a 50% increase in PSA and &gt;5 ng/mL increase from baseline or post-treatment nadir and confirmed. Endpoints included the proportion of pts who did not have PSA progression for 24 weeks, change in PSA slope/PSADT, and assessment of safety and tolerability. The study was not powered to detect difference between the two groups. Results: 52 pts were enrolled at 6 centers. Fourteen of 27 (52%) in the low dose and 6/25 (24%) in the high dose cohort were PSA progression free for 24 weeks. One patient in high dose cohort showed PSA &gt;50% decrease of 40 days duration. Pre- and on-treatment PSA kinetics are shown below. Median duration on study was 134 days in both groups. ATN-224 was well tolerated with a few reversible Grade 3/4 neutropenia and Grade 3 skin rash (both 4%). Conclusions: ATN-224 may have biologic activity in men with androgen-dependent PCa at low doses, as demonstrated by &gt; 50% of pts being PSA progression free at 6 month and a significant decrease in mean PSA slope. The implication of this study is not clear without a comparative design and ceruloplasmin correlation which is still pending. [Table: see text] [Table: see text]

Results from the Phase I Portion of a Phase I/II Study of ATN-224 and Bortezomib for Patients with Multiple Myeloma Relapsed from or Refractory to Bortezomib

ATN-224 (bis-choline tetrathiomolybdate) is an orally-available small molecule that is currently being studied in several phase II oncology clinical trials. ATN-224 inhibits copper-zinc superoxide dismutase (Cu/Zn-SOD; SOD1) in endothelial and tumor cells. SOD1 is an enzyme that mediates signaling by a number of mitogens including VEGF, FGF-2, EGF, IGF-1 and PDGF. The inhibition of SOD1 by ATN-224 leads to the inhibition of proliferation in endothelial cells and the induction of apoptosis in tumor cells. In a preclinical mouse model using multiple myeloma (MM) cells obtained from a patient that was refractory to bortezomib, the combination of ATN-224 and bortezomib was more effective than either agent alone and led to tumor regression. Based on this data, a phase I/II clinical study evaluating the combination of ATN-224 and bortezomib for MM patients that had previously failed bortezomib was initiated. The phase I portion of this study evaluated the safety of several doses of both ATN-224 and bortezomib and established a recommended dose and schedule of this combination for the phase II portion of the study. The phase I study has completed enrollment and results are presented here. Patients with recurrent or refractory MM that had previously failed bortezomib and currently showing evidence of disease progression were enrolled. Patients had adequate ECOG performance status (PS 0–2) and hematologic and organ function. Patients were monitored for safety and preliminary evidence of efficacy. Blood samples were collected at specific intervals for pharmacokinetic and pharmacodynamic analyses. Twenty-one patients (62% male), aged 46–80 (mean 66) with PS 0–1 were enrolled into 6 cohorts. Dose Limiting Toxicity (DLT) was defined as grade 3 or 4 neutropenia with neutropenic fever, grade 4 neutropenia, grade 3 or 4 thrombocytopenia, grade 2 peripheral neuropathy with pain, grade 3 or 4 neuropathic pain and/or peripheral sensory neuropathy, grade 4 anemia or a fall in hemoglobin by >3 g/dL when day 1 hemoglobin is ≥11 g/dL or >2 g/dL when day 1 hemoglobin is <11 g/dL over a 28-day interval, or any grade 3 or 4 non-hematologic treatment-related toxicity (excluding alopecia) that cannot be reduced to grade 2 or less with symptomatic therapy within 7 days. In the initial 3 cohorts of the trial (n=10), ATN-224 was administered at doses of either 240, 180, or 210 mg daily in combination with bortezomib at a dose of 0.7 mg/m2/dose on days 1, 4, 8 and 11 of a 21 day cycle. Several DLTs [hemoglobin decreased >2g/dL from baseline (n=3) and grade 3 fatigue (n=1)] were observed within the first three cohorts. After review of this data, it was determined that the more appropriate dosing schedule included a 7 day drug holiday. In cohorts 4 through 6 (n=11), ATN-224 was administered at doses of either 180 or 210 mg daily for 21 days in combination with bortezomib at a dose of either 1.0 or 1.3 mg/m2/dose on days 8,11, 15 and 18 of a 28 day cycle. One DLT (grade 4 thrombocytopenia) was observed and occurred in the 180 mg ATN-224 plus 1.3mg/m2/dose bortezomib cohort. By incrementally increasing each dose of ATN-224 and bortezomib individually and modifying the treatment schedule, treatment-related toxicities have been minimized while maximizing the treatment doses. One patient experienced a complete response that was durable for over 10 months. The other 20 patients experienced disease progression within 90 days. A daily dose of 210 mg of ATN-224 for 21 days and a dose of bortezomib at 1.0 mg/m2 on days 8, 11, 15, and 18 of a 28 day cycle was well tolerated and recommended for the phase II portion of this trial, which is now enrolling patients. The phase I portion of the study demonstrates that the combination of ATN-224 and bortezomib can be safely administered and may be an effective treatment for MM patients that are relapsed from or refractory to bortezomib.