Clinical Drug Experience Knowledgebase

Double-blind, Randomised, Placebo-controlled Parallel Group Study to Investigate the Effect of EGCG Supplementation on Disease Progression of Patients With Multiple System Atrophy (MSA)

5 Introduction Multiple System Atrophy (MSA) is a slowly progressing neurodegenerative disease that is characterized by i) a hypokinetic movement disorder which defines MSA of the parkinsonian type (MSA-P) or by ii) cerebellar symptoms which define MSA of the cerebellar type (MSA-C). In both types the movement disorder can be accompanied by vegetative symptoms such as orthostatic hypotension. In contrast to Parkinson's disease (PD), the effect of dopaminergic medication on the parkinsonian symptoms is very limited. In spite of several efforts, no disease modifying therapy has been identified so far. Several lines of evidence including epidemiological, in vitro, and in vivo data, suggest that Epigallocatechin gallate (EGCG) might be able to delay disease progression of MSA by modifying several aspects in the pathogenesis of MSA such as protein aggregation, oxidative stress and iron accumulation. Therefore, this study is designed to investigate the influence of EGCG on disease progression in patients with MSA. To assess the effect on disease progression, clinical evaluation and MR-imaging will be applied in a bi-center, prospective, placebo-controlled, double-blind randomized phase III trial. The primary outcome measure will be the change in motor symptoms from V1 to V7 measured by the UMSARS-ME comparing placebo- vs. verum-treated patients. The secondary efficacy endpoint will be the change from V1 to V7 in the total UMSARS score, in the CGI score and in MRI parameters (global and regional atrophy / iron deposition) comparing placebo- vs. verum-treated patients.

5.1 Background The disease: MSA is a synucleinopathy that is suitable for various reasons as a model disease to investigate disease-modifying effects in α-synuclein (aSyn)-dependent neurodegeneration. The disease progression is more rapid compared to PD and therefore allows the observation of clinically relevant effects in shorter observation periods. As no potent symptomatic treatment of MSA is currently available, the influence of symptomatic active substances on clinical data is limited and placebo can be used as comparator. This solves the potential ethical problem of having to deprive patients of such symptomatic treatment during the study and underlines the high medical need for a symptomatic treatment. Another important argument for neuroprotection studies in MSA is that in three independent studies EMSA, NNIPPS, MEMSA a very similar disease progression was observed over a defined period of time, which enables a precise power analysis with sample sizes and follow-up periods that are suitable for an investigator initiated trial (IIT).

The therapeutic target: An increasing amount of data suggests that toxic oligomers from misfolded, disease-specific proteins play a potentially important role in the neuronal cell death in neurodegenerative diseases. Specifically in MSA, oligomeric aSyn aggregate species appear to be crucially involved in the pathogenetic mechanisms.

The pharmacological compound: Epidemiological data suggest that ingredients in tea may be neuroprotective for synucleinopathies in man. Regular consumption of tea reduces the risk of contracting PD by about 50%. Also for MSA, a clear trend in the sense of a positive effect of tea consumption on the risk of disease development was observed (OR = 0.5, 95% CI: 0.22-1.5, p = 0.09). EGCG, a polyphenol that is for example found in green tea, inhibits the formation of toxic aSyn oligomers in vitro and transforms aSyn oligomers by direct interaction in alternative, non-toxic oligomer species. Furthermore, EGCG shows a neuroprotective effect in the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP) mouse model of PD. In addition, EGCG is an antioxidant and an iron chelator and therefore has more potential beneficial effects on synucleinopathies.

The pharmacokinetic properties of EGCG were tested in humans in the serum and in rodents in serum and organs, including the brain in detail. It was found that repeated oral application of doses of EGCG result in a significant increase in serum levels in healthy adults compared to a single dose. The proposed daily dose of 1200 mg of EGCG is comparable to about 15 to 30 cups of green tea (depending on the mode of preparation) (Prof. F. Paul, Berlin, pers. comm.). Animal experiments in rodents have shown that after a single i.v. dose of EGCG, the substance is found in the brain in significant quantities.

5.2 Trial Rationale MSA is a rapidly progressive disorder with an average survival time of about 7 years after the first clinical manifestation. No potent symptomatic treatment is currently available. A disease-modifying therapy does not exist either. The growing understanding in recent years of the underlying pathological mechanisms of the disease allows the development of new treatment options that have a modifying effect on the disease progression. Therefore, treatments are urgently required that effect the central underlying pathological mechanism, which appears to be the intracellular aggregation of toxic oligomers of aSyn.

EGCG, a polyphenol found in green tea, has shown to inhibit the formation of toxic aSyn oligomers in vitro and has shown to transform aSyn-oligomers in non-toxic oligomer species. There is also evidence for a neuroprotective effect in MPTP-mouse models of PD and is an antioxidant and iron chelator. There are currently 63 clinical studies in which EGCG was applied for various indications, such as Multiple Sclerosis, various forms of cancer and Huntington's disease. All of which have shown good tolerability and safety with the applied doses of EGCG of up to 1200 mg per day, demonstrating the safety of the drug under controlled clinical conditions.

These data provide a solid rationale for testing in a clinical trial if supplementation of EGCG can interfere with the core disease mechanism in MSA and consequently retard the clinical progression of the MSA-related disability.

5.3 Side effects and Risk Benefit Assessment 5.3.1 Side effects In all clinical trials investigating the oral intake of green tea/EGCG in various doses and pharmacological forms, EGCG has shown a good safety and tolerability in daily doses of up to 1200 mg over a period of 6 months. Side effects that have been reported after application of EGCG were usually mild and did not occur more often than under placebo (flatulence, headache, nausea, vertigo, abdominal cramps and muscle pain). Other reported side effects (arterial hypertension, palpitations, headache, polyuria, tremor, sleep disorders, nausea/vomiting) are due to the caffeine part in green tea and are not due to EGCG, as all studies using pure EGCG have not reported such side effects.

No relevant or persistent changes in the extensive clinical serum tests have been found so far; also no influence on vital parameters have been reported after using EGCG. Only minimal and transient changes of the blood pressure, echocardiography, liver function tests and serum lipids have been reported. In a study of Chow et al. healthy subjects were given 800 mg EGCG or Polyphenon E (a mixture of several green tea extracts with a 50-75%share of EGCG) once daily or 400 mg twice daily versus placebo over a period of 4 weeks. Only mild side effects occurred in several subjects (flatulence, abdominal pain, nausea, headache, dizziness and muscle pain) that were not occurring more often than under placebo.

The SuniMS study, NCT ID: 00525668, recorded no SUSAR in 120 patients with remitting-relapsing MS, who were administered 800 mg Sunphenon/ EGCG per day. They also were able to show an excellent tolerability. Only 15 patients showed mild, clinically insignificant elevations of liver function tests, which are not necessarily caused by the study medication. The ongoing SUPREMES study, NCT ID: 00799, has so far not recorded any SUSAR in 60 patients with progressive MS who have been on up to 1200 mg EGCG/day for up to 48 months.

In a study by Chen et al a significant protective effect of orally applied EGCG could be demonstrated in mice with a toxic liver failure caused by tetrachlorohydrocarbons. Otherwise, single cases of hepatotoxicity following application of various forms of green tea polyphenols are known. In the period between 1999 and 2008, 34 such case reports have been published, 29 of which have shown a positive de-challenge and 7 have shown a positive re-challenge. The clinical and pathological symptoms included mild elevations of liver function tests, cholestasis, cholangitis, hepatocellular inflammation and hepatocellular necrosis. The symptoms were usually completely reversible after stopping the medication. One patient died of liver failure. Signs of liver toxicity were recorded between day 9 up to 5 months after beginning a therapy with doses of 187,5 -468,75mg EGCG/day).

The withdrawal of a green tea extract in Spain and France (Exolise®) a couple of years ago needs to be mentioned. After application of this medication some cases of severe hepatotoxicity were reported. Symptoms like icterus, massive elevation of transaminases occurred not later than 12 weeks after beginning the treatment with the extract in capsules and were completely reversible few weeks after stopping the medication. The exact underlying mechanisms have not been completely worked out. Possibly these are due to a SAE that is specific for Exolise®, and is connected with the manufacturing process (hydro-alcoholic extraction techniques). For this reason, only the distribution of Exolise® has been stopped by the respective authorities, but not the distribution of other green tea extracts (see also the following publications by the WHO): www.who.int/entity/medicines/publications/restrictedpharm2005.pdf It has not yet been found out which parts of the polyphenols and their metabolites are responsible for the hepatotoxic effects. Even though in most cases mixtures of green tea and polyphenols have been administered it is suspected, that EGCG as a main component of the green tea extracts shows hepatotoxic potential. In favor of this hypothesis is the fact, that there have been reports of elevated transaminases under treatment with EGCG in man and interactions with other substances. EGCG is known to bind to α- and β-estrogene receptors and increases 17 β-estradiol-induced reactions in mice. EGCG is a known inhibitor of the Catechol-O-methyltransferase (COMT) that catalyses the degradation of exogenous and endogenous substances.

It is suspected, that for the biotransformation of green tea catechines, COMT plays an important role. COMT polymorphisms with low activity of COMT could result in elevated plasma levels of toxic EGCG metabolites.

The cytotoxicity of EGCG in hepatocytes seems to be low in vitro and only doses that are higher by a multiple compared to the doses used in clinical studies lead to liver necrosis in animal models. Also, the extremely low bioavailability in man has to be considered.

On the basis of all recent studies using green tea extract and EGCG there are no reports of persistent and severe influence on the physiological systems (blood circulation, respiratory system, central nervous system and urinary tract). Still there are singular case reports of hepatotoxic effects in the context of intake of green tea extracts/ EGCG.

As a conclusion, all data are in favor of a good tolerability of the substance. For further details see the investigator's brochure (Polyphenon E).

5.3.2 Risk Benefit Assessment The reported data suggest a safe pharmacological profile apart from individual cases of hepatotoxicity which can be controlled for by routine serum liver parameters. The preclinical data suggest a molecular mode of action for EGCG which appears to target core pathological mechanisms active in MSA. In absence of any effective symptomatic, protective or curative intervention in this devastating disorder, the risk benefit evaluation justifies the conduct of the proposed clinical trial.