The promise of copper lowering therapy with tetrathiomolybdate in the cure of cancer and in the treatment of inflammatory disease.

Tetrathiomolybdate (TM) is a unique anticopper drug developed for the treatment of the neurologic presentation of Wilson's disease, for which it is excellent. Since it was known copper was required for angiogenesis, TM was tested on mouse cancer models to see if it would inhibit tumor growth based on an antiangiogenic effect. TM was extremely effective in these models, but all the tumors in the models started small in size - micrometastatic in size. Later, TM was tested in numerous human cancer trials, where it showed only modest effects. However, the mouse lesson of efficacy against micro disease was forgotten - all the trials were against bulky, advanced cancer. Now, the mouse evidence is coming back to life. Three groups are curing, or having major efficacy of TM, against advanced human cancers, heretofore virtually incurable, particularly if the cancer has been reduced to no evidence of disease (NED) status by conventional therapy. In that situation, where the remaining disease is micrometastatic, TM therapy appears to be curative. We have designed and initiated a study of TM in canine osteosarcoma at the micrometastatic phase to help put these findings on a firm scientific basis. TM also has major anti-inflammatory properties by inhibiting copper dependent cytokines involved in inflammation. This anti-inflammatory effect may be involved in TM's anticancer effect because cancers, as they advance, attract inflammatory cells that provide a plethora of additional proangiogenic agents.

Treatment of primary biliary cirrhosis with tetrathiomolybdate: results of a double-blind trial.

The results of a double-blind trial of tetrathiomolybdate therapy and standard of care, versus placebo and standard of care treatment, in primary biliary cirrhosis patients are presented. Baseline studies of liver function, various safety variables, ceruloplasmin, a liver biopsy for histologic analysis, and for various cytokine analyses were carried out. Patients were observed every 4 months for up to 2 years of treatment by a hepatologist for clinical evaluation and repeat of all the baseline studies except liver biopsy, which was repeated at 2 years. The primary end points were improvement in 2 liver function tests and in 1 inflammatory cytokine. Fifteen placebo patients were followed for an average of 13 months, and 13 tetrathiomolybdate patients were followed for an average of 14 months. The predefined primary end points for efficacy were met. Tetrathiomolybdate was well tolerated. Because tetrathiomolybdate has been shown in numerous animal studies to inhibit autoimmune and inflammatory processes, and because primary biliary cirrhosis is an autoimmune attack on bile ducts, these positive findings on efficacy of tetrathiomolybdate therapy in primary biliary cirrhosis fit with the animal studies and suggest the need for a longer clinical trial to examine transplant-free survival.

Risks of copper and iron toxicity during aging in humans.

Copper and iron are essential but also toxic metals. Their essentiality is known, but their toxicity, except for the genetic overload diseases, Wilson's disease and hemochromatosis, is not so well known. Yet, their toxicities are so general in the population that they are a looming public health problem in diseases of aging and in the aging process itself. Both metals are transition elements, and their resulting redox properties have been used during evolution in the development of oxidative energy generation. But both contribute to the production of excess damaging oxidant radicals. Evolution has kept stores of copper and iron in excess during the reproductive years because they are so vital to life. But the oxidant damage from these excess stores of metals builds up as we age, and natural selection ceases to act after about age 50 since diseases after that do not contribute to reproductive fitness. Diseases of aging such as Alzheimer's disease, other neurodegenerative diseases, arteriosclerosis, diabetes mellitus, and others may all be contributed to by excess copper and iron. A very disturbing study has found that in the general population those in the highest fifth of copper intake, if they are also eating a relatively high fat diet, lose cognition at over three times the normal rate. Inorganic copper in drinking water and in supplements is handled differently than food copper and is therefore more toxic. Trace amounts of copper in drinking water, less than one-tenth of that allowed in human drinking water by the Environmental Protection Agency, greatly enhanced an Alzheimer's-like disease in an animal model. In the last part of this review, I will provide advice on how to lower risks from copper and iron toxicity.

A pilot trial of the anti-angiogenic copper lowering agent tetrathiomolybdate in combination with irinotecan, 5-flurouracil, and leucovorin for metastatic colorectal cancer.

Tetrathiomolybdate (TM) is an oral copper chelator under development as an anti-angiogenic agent. We evaluated TM in combination with irinotecan, 5-fluorouracil, and leucovorin (IFL). Serum vascular endothelial growth factor (VEGF), basic fibroblast growth factor, interleukin 6 (IL-6), and IL-8 were measured to evaluate the anti-angiogenic effect. Twenty-four patients with metastatic colorectal cancer were treated. The combination with IFL was well tolerated and dose intensity of IFL was maintained during combination therapy with TM. By intention to treat analysis, the overall response rate (RR) was 25% (95% CI 9.8-46.7) and the median time to progression (TTP) was 5.6 months (95% CI 2.7-7.7). VEGF levels were correlated with TTP, as were changes in VEGF, IL-8, and IL-6. TM can be safely added to IFL without compromising dose intensity or diminishing the expected RR. Changes in serum VEGF, IL-8, and IL-6 after treatment may directly reflect changes in CRC tissue angiogenesis.

The use of copper-lowering therapy with tetrathiomolybdate in medicine.

BACKGROUND: Tetrathiomolybdate (TM), an anticopper drug, has been developed for the neurologic presentation of Wilson's disease. In animal models, lowering copper levels with TM produces antifibrotic, anti-inflammatory, antiautoimmune, and anticancer effects, thought to be due to inhibition of many cytokines that are dependent on available copper for their activity. Clinical testing has been done relatively extensively in Wilson's disease and advanced cancers, but remains in its infancy in other diseases. OBJECTIVES: To review current preclinical and clinical studies done with TM, and our current knowledge of TM efficacy and toxicity. METHODS: We have reviewed the last 10 years of literature on TM therapy. RESULTS/CONCLUSION: TM has excellent efficacy and acceptable toxicity for the initial treatment of neurologically presenting Wilson's disease. TM has excellent efficacy in animal models of fibrotic, inflammatory, autoimmune, and neoplastic diseases, as well as Alzheimer's disease models.

The risks of free copper in the body and the development of useful anticopper drugs.

PURPOSE OF REVIEW: To review the toxicity and risks of free copper in Wilson's disease, Alzheimer's disease, other disease of neurodegeneration, and cognitive loss in the general population. We will also review the anticopper drugs and how lowering free copper levels with an anticopper drug inhibits fibrosis, inflammation, and autoimmunity. RECENT FINDINGS: Some exciting recent work indicates that free copper levels are increased in Alzheimer's disease, and copper may be involved in disease pathogenesis, opening the way to possible therapy of Alzheimer's disease with anticopper drugs. Copper may also be involved in other diseases of neurodegeneration. A very exciting recent study indicts high intake of copper, mostly from copper supplements, in conjunction with a high-fat diet in more rapid cognitive decline in the general population. Other data indicate that even low levels of copper in drinking water, perhaps similar to copper supplements, bypasses the liver, enters the circulation, increases the blood-brain penetration of copper, and may cause damage. SUMMARY: Some of the implications are that Alzheimer's disease and other diseases of neurodegeneration and fibrotic, inflammatory, and autoimmune diseases may be treatable by lowering the availability of free copper. People in the general population may wish to take steps to lower their free copper levels and, in particular, to abstain from taking copper supplements and ingesting significant amounts of copper in drinking water.

A phase II trial of tetrathiomolybdate after surgery for malignant mesothelioma: final results.

BACKGROUND: Tetrathiomolybdate (TM) is an oral copper-depleting agent that has been shown to inhibit angiogenesis, and angiogenesis is a predictor of poor prognosis in malignant pleural mesothelioma. We hypothesized that cytoreduction of malignant pleural mesothelioma followed by TM will delay time to progression. METHODS: Between November 2000 and August 2003, 30 patients with malignant pleural mesothelioma received postoperative TM beginning 4 to 6 weeks after surgery at a dose adjusted to keep ceruloplasmin between 5 and 15 mg/dL). Time to progression was compared with the 55 stage I and II patients and 109 stage III patients previously treated with cytoreduction by one of us (H.P.). RESULTS: The 30 patients (25 men, 5 women; 13 stage I and II, 17 stage III), median age 67 years (range, 49-81 years), remained on TM a median of 14.9 months (range, 2 to 57 months). All patients reached target ceruloplasmin levels at a mean of 34 +/- 2 days (95% confidence interval, 30 to 39 days), and vascular endothelial growth factor levels at baseline (ceruloplasmin = 45.2 +/- 2 mg/dL) decreased from 2,086 +/- 390 pg/mL to 1,250 +/- 712 pg/mL (p < 0.002) at target ceruloplasmin (13 +/- 2 mg/dL; p < 0.0001 from baseline). The time to progression for all stage I or II TM patients was 20 months whereas that of 55 stage I or II non-TM-treated patients was 10 months (p = 0.046 versus TM). No differences in time to progression for the stage III TM patents from surgery were seen (7 months). CONCLUSIONS: Tetrathiomolybdate has antiangiogenic effects in malignant pleural mesothelioma patients after resection of gross disease, and exhibits minimal toxicity and comparable efficacy to previous multimodality trials. Tetrathiomolybdate should be evaluated for efficacy in combination with standard malignant pleural mesothelioma regimens, as well as for postsurgical maintenance therapy.

Tetrathiomolybdate protects against bile duct ligation-induced cholestatic liver injury and fibrosis.

Tetrathiomolybdate (TM), a potent copper-chelating drug, was initially developed for the treatment of Wilson's disease. Our working hypothesis is that the fibrotic pathway is copper-dependent. Because biliary excretion is the major pathway for copper elimination, a bile duct ligation (BDL) mouse model was used to test the potential protective effects of TM. TM was given in a daily dose of 0.9 mg/mouse by means of intragastric gavage 5 days before BDL. All the animals were killed 5 days after surgery. Plasma liver enzymes and total bilirubin were markedly decreased in TM-treated BDL mice. TM also inhibited the increase in plasma levels of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 seen in BDL mice. Cholestatic liver injury was markedly attenuated by TM treatment as shown by histology. Hepatic collagen deposition was significantly decreased, and it was paralleled by a significant suppression of hepatic smooth muscle alpha-actin and fibrogenic gene expression in TM-treated BDL mice. Although the endogenous antioxidant ability was enhanced, oxidative stress as shown by malondialdehyde and 4-hydroxyalkenals, hepatic glutathione/oxidized glutathione ratio, was not attenuated by TM treatment, suggesting the protective mechanism of TM may be independent of oxidative stress. In summary, TM attenuated BDL-induced cholestatic liver injury and fibrosis in mice, in part by inhibiting TNF-alpha and TGF-beta1 secretion. The protective mechanism seems to be independent of oxidative stress. Our data provide further evidence that TM might be a potential therapy for hepatic fibrosis.

Antitumor and antiinflammatory effects of tetrathiotungstate in comparison with tetrathiomolybdate.

Tetrathiomolybdate (TM) is an anticopper drug under development for treating Wilson's disease. Its mechanism of action involves forming a tight tripartite complex in the blood with serum albumin and available copper. When available copper levels are lowered in animals with TM, strong antiangiogenic and antitumor effects are observed. Similarly, TM has excellent efficacy in animal models of fibrotic, inflammatory, and autoimmune diseases, and it protects against heart damage from doxorubicin (DXR) and liver damage from acetaminophen, carbon tetrachloride, and concanavalin A. Tetrathiotungstate (TT) also forms a similar tripartite complex in the blood and has similar effects to TM on copper. In this article, whether TT had similar antitumor effects, and similar effects in protecting the heart against DXR toxicity, as TM was evaluated. It was found that the 2 drugs were comparable in their effects when doses were used that lowered copper availability to the same extent.

Iron and copper toxicity in diseases of aging, particularly atherosclerosis and Alzheimer's disease.

In this review, we point out that natural selection does not act to lessen human diseases after the reproductive and caregiving period and that normal levels of iron and copper that may be healthy during the reproductive years appear to be contributing to diseases of aging and possibly the aging process itself. It is clear that oxidant damage contributes to many of the diseases of aging, such as atherosclerosis, Alzheimer's disease, Parkinson's diseases, diabetes, diseases of inflammation, diseases of fibrosis, diseases of autoimmunity, and so on. It is equally clear that both iron and copper can contribute to excess production of damaging reactive oxygen species through Fenton chemistry. Here, we examine the evidence that "normal" levels of iron and copper contribute to various diseases of aging.

Tetrathiomolybdate is effective in a mouse model of arthritis.

OBJECTIVE: To test for protective effects of therapy with tetrathiomolybdate, a copper-lowering drug, against collagen-induced arthritis in mice. METHODS: Mice were injected with bovine collagen II, and limb joint swelling and erythema were scored. Tetrathiomolybdate treated mice received drug by oral gavage or in drinking water. Plasma ceruloplasmin was followed as a measure of body copper status, and maintained between 20 and 60% of baseline. Urine for isoprostane studies was collected in metabolic cages. At sacrifice, blood was collected for cytokine assays, and hind limbs fixed in formalin. RESULTS: Tetrathiomolybdate strongly protected against the collagen-induced arthritis as reflected in scores of swelling and erythema, and as seen histologically. Further, tetrathiomolybdate strongly protected against the increase in urine isoprostanes (a marker of oxidant damage) seen in collagen treated controls. The drug also protected against the increase in interleukin 2, interleukin 1beta, and tumor necrosis factor-a levels seen in collagen treated controls. CONCLUSION: Based on the positive results reported here, and the good safety profile of tetrathiomolybdate in human studies so far, a trial of tetrathiomolybdate in arthritis syndromes seems warranted.

Comparison of lowering copper levels with tetrathiomolybdate and zinc on mouse tumor and doxorubicin models.

Tetrathiomolybdate (TM), presumably by lowering copper levels and availability, has shown excellent efficacy in animal models of cancer and models of injury that produce fibrotic or inflammatory damage in lung, heart, and liver. Trials in human patients are underway. If the efficacy of TM is indeed through lowering copper levels, other anticopper drugs should be equally efficacious. Zinc is an anticopper drug, with proven efficacy in Wilson's disease, a disease of copper toxicity. In this study, the efficacy of zinc is compared with TM on a mouse tumor model and on the doxorubicin model of heart damage, and it is hypothesized that when copper availability is lowered to an equivalent extent, the 2 drugs would show equivalent efficacy. No effect is found of zinc on inhibiting growth of a tumor that is markedly inhibited by TM, and zinc is found to be less effective than TM in inhibiting cardiac damage from doxorubicin. This study shows that TM's mechanism of action in protecting against doxorubicin toxicity is because of its anticopper effects, as copper supplementation eliminated the protective effect of TM. It is also hypothesized that the differences between TM and zinc may be caused by TM's mechanism of action in which it binds copper already in the body, whereas zinc does not.

The use of tetrathiomolybdate in treating fibrotic, inflammatory, and autoimmune diseases, including the non-obese diabetic mouse model.

Tetrathiomolybdate was originally developed for use in Wilson's disease. However, lowering copper levels to below normal levels with tetrathiomolybdate has been found to have efficacy in cancer, probably by turning down signaling by angiogenic cytokines. More recently, we have shown in animals models that tetrathiomolybdate dramatically inhibits pulmonary and liver fibrosis. In other animal models, we have shown that the drug also inhibits liver damage from concanavalin A and acetaminophen, and heart damage from doxorubicin. These studies are briefly reviewed, and we then present data on tetrathiomolybdate's partially protective effect against diabetes in non-obese diabetic mice, an autoimmune model of type I diabetes. Possible mechanisms of tetrathiomolybdate's protective effect are briefly considered.

Control of copper status for cancer therapy.

Copper is a trace element which is tightly regulated in mammals and lower animals. Disruptions of copper homeostasis in humans are rare and they cause serious disorders such as Wilson's disease and Menke's disease. Copper plays an important role in promoting physiological and malignant angiogenesis. Formation of new blood vessels by a tumor enables tumor growth, invasion, and metastasis are copper requiring processes. The copper chelator tetrathiomolybdate (TM), which quickly and effectively depletes copper stores, is under investigation as an anti-angiogenic agent. Promising results from in vitro experiments, in pre-clinical animal models, and in a phase I clinical trial have led to several phase II trials of TM in patients with advanced cancers.

Tetrathiomolybdate protects against cardiac damage by doxorubicin in mice.

Cardiac toxicity is the limiting factor in therapy with doxorubicin, an otherwise useful cancer drug. In this article we detail our study of a mouse model of doxorubicin-induced cardiac toxicity in which, after 4 days' treatment, doxorubicin caused marked increases in plasma concentrations of creatine kinase, lactic dehydrogenase, and troponin I, indicators of cardiac injury; marked increases in the plasma concentrations of tumor necrosis factor-alpha and interleukin-1(beta), both inflammatory cytokines; and a marked increase in the plasma concentration of interleukin-2, an indicator of cytotoxic T-cell activation. Therapy with tetrathiomolybdate, designed to limit copper availability, eliminated almost all of the increases of these six parameters in plasma. The marked protection against cardiac injury by doxorubicin in tetrathiomolybdate-treated animals suggests that tetrathiomolybdate would be of use clinically in helping prevent doxorubicin toxicity in patients. In other preclinical work, it has been shown that tetrathiomolybdate potentiates the chemotherapeutic effect of doxorubicin in cancer, so a double benefit might accrue clinically from the combined use of tetrathiomolybdate and doxorubicin. The mechanism by which tetrathiomolybdate protects against doxorubicin toxicity is of considerable interest. Our working hypothesis, based on the inhibition of interleukin-2 by tetrathiomolybdate as shown here, is that tetrathiomolybdate interrupts the inflammatory cascade at the activated-T-lymphocyte stage.

Anticopper therapy against cancer and diseases of inflammation and fibrosis.

Anticopper drugs that have been developed to treat Wilson's disease, a disease of copper toxicity, include tetrathiomolybdate, zinc, penicillamine, and trientine. Lowering copper levels by a modest amount in non-Wilson's patients with tetrathiomolybdate inhibits angiogenesis, fibrosis and inflammation while avoiding clinical copper deficiency. Through this mechanism tetrathiomolybdate has proven effective in numerous animal models of cancer, retinopathy, fibrosis, and inflammation. Penicillamine has efficacy in rheumatoid arthritis and trientine has efficacy in diabetic neuropathy and diabetic heart disease. If clinical studies support the animal work, anticopper therapy holds promise for therapy of cancer, fibrotic disease and inflammatory and autoimmune diseases.

Copper lowering therapy with tetrathiomolybdate as an antiangiogenic strategy in cancer.

Tetrathiomolybdate (TM) is a novel anticopper agent under development for use in Wilson's disease. It acts by forming a stable tripartite complex with serum albumin and copper, rendering the complexed copper unavailable for cellular uptake. TM is a very potent anticopper agent and has an excellent safety profile. It has been shown that normal copper levels are required for optimal angiogenesis. Based on this background, we decided to evaluate TM as an anticancer agent. TM treatment of Her/2neu mice, genetically programmed to develop breast cancer, completely prevented the development of visible mammary cancers, although avascular microscopic clusters of cancer cells were present in the breasts of TM treated animals. Controls developed grossly visible tumors. TM was able to strongly inhibit tumor growth in six other rodent models. In a phase 1/2 clinical trial of advanced and metastatic cancers, freedom from progression averaged 11 months, and some individual results were quite dramatic. Eight phase 2 studies of specific cancers have been launched. TM's hypothesized mechanism of action is inhibition of angiogenic cytokines. Unlike other current approaches to antiangiogenic therapy which target single agents, we hypothesize that TM inhibits multiple angiogenic cytokines. Part of this effect appears to stem from inhibition of nuclear factor kappa B (NF(K)B), which in turn controls transcription of many angiogenic and other cytokines. However, there are probably multiple mechanisms, in that some angiogenic cytokines appear to have separate mechanisms of copper dependence. The inhibition of multiple angiogenic cytokines gives TM the potential to be a more global inhibitor of angiogenesis.

Effects of tetrathiomolybdate in a mouse model of retinal neovascularization.

PURPOSE: To determine the effects of tetrathiomolybdate (TM), a copper-chelating agent, on retinal angiogenesis and vascular endothelial growth factor (VEGF) in a mouse model of retinal neovascularization. METHODS: Postnatal day (P)7 C57BL/6N mice were exposed to 75% +/- 2% oxygen for 5 days (P7-P11) and then returned to room air for 5 days (P12-P17) to induce retinal neovascularization. Beginning on P10 or P12, mice received daily intraperitoneal injections of TM or phosphate-buffered saline (PBS; control) through P17. Retinal neovascularization was examined by fluorescein dextran angiography after 5 days in room air and was quantitated histologically by counting the neovascular endothelial cell nuclei anterior to the inner limiting membrane. TM's effects on VEGF expression were measured by ELISA. RESULTS: TM-treated and control animals demonstrated comparable regions of retinal nonperfusion. Retinas from control mice at P17 contained neovascular tufts at the junction between perfused and nonperfused retina. The tufts contained numerous neovascular nuclei. Retinas from mice treated with TM beginning on P10 (2 days before returning to room air), but not P12, demonstrated a 41% reduction in neovascular cell nuclei compared with control mice (P <0.01). The P10-treated mice also demonstrated a 24% reduction of VEGF compared with control animals (P=0.01). CONCLUSIONS: TM significantly inhibits retinal neovascularization and VEGF production in a mouse model of retinal neovascularization.

Inhibition of key cytokines by tetrathiomolybdate in the bleomycin model of pulmonary fibrosis.

Tetrathiomolybdate is an anticopper drug with a unique mechanism of action. Tetrathiomolybdate complexes copper to protein and itself, rendering the copper unavailable for cellular uptake. It was originally developed for Wilson's disease, and is now being developed as an antiangiogenic agent for the treatment of cancer. Many angiogenic cytokines require normal levels of copper, and lowered copper levels reduce cytokine signaling while cellular copper requirements are met. Cytokines of fibrosis and inflammation may be similarly copper dependent, since tetrathiomolybdate inhibits bleomycin induced pulmonary inflammation and fibrosis. The basis for this inhibition was evaluated here by examination of tetrathiomolybdate effects on cytokines in lung pathophysiologically important in the bleomycin mouse model of pulmonary damage. Results in mice injected endotracheally with bleomycin confirmed that tetrathiomolybdate therapy was effective in reducing fibrosis. This effect was associated with significant inhibition of bleomycin-induced tumor necrosis factor alpha and transforming growth factor beta expression in lung homogenates. These effects were shown to be independent of one another. This indicates that tetrathiomolybdate therapy can be effective even when fibrosis is at a more chronic stage, wherein inflammatory cytokines are playing a diminishing role. The inhibition of tumor necrosis factor alpha suggests that diseases of tumor necrosis factor alpha overexpression are also potential targets of tetrathiomolybdate therapy.

Tetrathiomolybdate therapy protects against concanavalin a and carbon tetrachloride hepatic damage in mice.

Tetrathiomolybdate, an anticopper drug, has been shown to protect mice against pulmonary fibrosis from bleomycin. Our hypothesis is that it does so by inhibiting fibrosis-inducing cytokines. Indeed, we have good evidence, not yet published, that tetrathiomolybdate inhibits pulmonary levels of transforming growth factor-beta and tumor necrosis factor-alpha expression in these bleomycin experiments. Herein, we evaluate tetrathiomolybdate's effectiveness in mitigating hepatitis and fibrosis in mice from the hepatotoxins, concanavalin A and carbon tetrachloride, and its inhibition of cytokines as a possible mechanism. In short-term experiments, concanavalin A elevated serum amino leucine transferase levels several fold, and tetrathiomolybdate completely prevented this increase. In additional experiments, tetrathiomolybdate therapy reversed the elevated serum transaminase levels despite continued concanavalin A injections, with nearly significant serum interleukin-1beta inhibition. Concanavalin A given for 12 weeks produced mild fibrosis, whereas concomitant tetrathiomolybdate treatment resulted in normal histology. Carbon tetrachloride given for 12 weeks resulted in very high serum amino leucine transferase levels, high serum transforming growth factor-beta levels, cirrhosis as seen histologically, and increase in liver hydroxyproline, a measure of fibrosis. Concomitant tetrathiomolybdate partially and significantly protected against increases in amino leucine transferase and transforming growth factor-beta, fully protected against the increase in hydroxyproline, and resulted in normal histology. In conclusion, tetrathiomolybdate protects against the hepatitis and fibrosis produced by these hepatotoxins, probably by inhibiting the excessive increase in inflammatory and fibrotic cytokines.