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We have a bit more news on Taranbant - the drug similar to Acomplia that is being developed by Merck.  We have been bringing our readers news on this medication on a regular basis and we thought that you might be interested in an article in the January issue of Cell Metabolism, which discusses the effectiveness of Taranabant at low doses over a 12 week period.

Taranabany works as a CB1 receptor inverse agonist whereas Acomplia is a CB1 receptor antagonist so they work in slightly different ways.  Taranabant appears to cause significant weight loss at doses which block just 30% of cannabinoid receptors in the brain.  Apparently the drug was effective at low doses of 0.5 mg to 6.0 mg.  This compares to a standard dose of 20 mg for Acomplia.

In a double blind trial involving 12 mg daily dose of Taranabant and a placebo, the Taranabant patients were observed to consume 27% fewer calories than those taking the placebo.  It was also observed the the Taranabant patients burned more fat and expended more energy while at rest.  This is a really exciting new drug and we hear that Merck will be applying to the FDA in the US by the end of this year.  It is not clear if they will be making a simultaneous application the the European Medicines Agency but this would make sense.  we have heard that they will not be making a simultaneous application but this has not been confirmed by the company.  As always, we will bring you more news when we receive it!

Orexigen Therapeutics has started recruiting for the final phase of the Phase III clinical trials for its lead obesity drug – Contrave.  We have previously written about Contrave on this news channel and you can see further details on this exciting new drug in our obesity archives.  Essentially Contrave combines a slow release form of bupropion and naltrexone.  The combination of these two drugs appears to control the amount of food that a patient consumes and the energy expended by that person.  In earlier clinical trials this was demonstrated to help people lose clinically significant amounts of weight compared with those patients on a placebo.  Orexigen has intimated that it intends to file for approval for this new medicine in 2009.

We have just seen the results of a study from a Canadian research team which suggests that the results that patients get from taking anti-obesity medications can sometimes be disappointing.  Whilst the research showed that there was a greater chance of achieving the weight loss required to get to a healthy body mass amongst people who take the medications than with those who do not, the results were quite often not that impressive.  A number of patients dropped out of the programme early on, which is something that we notice with some of our patients.  This non-adherence by patients is one of the major causes of disappointing weight loss results.  If participants do not follow instructions, it is hardly surprising that they do not lose weight!

The study looked at sibutramine, orlistat and Rimonabant – The Online Clinic routinely prescribes all of these medications.  We find that the results are very much mixed.  Some patients have amazing results whereas some drop out after the first month either because of cost or low levels of weight loss.  Unless there have been side effects, we would normally recommend continuing for three months to see if a 5% weight reduction could be achieved in that time frame.  Normally, with some persistence and a bit of effort on the exercise front, this result can be achieved by most patients.

The study found that those people taking the medications did get other results which have an overall positive impact on their health.  Xenical appeared to have an impact on reducing the incidence of diabetes and all the medications, including Reductil and Acomplia, had an impact in reducing certain cholesterol levels.

Scientists at Tel Aviv University have been working on a compound that really could be a “wonder weight loss drug.”  The drug is known as Histalean and is based on Betahistine, a drug that we have been prescribing for around 30 years to treat vertigo and meniere’s syndrome.  Betahistine is believed to block the H1 and H3 receptors in the brain.  These receptors are connected to a sense of fullness and a desire to eat fatty foods.

The results of a twelve week trial have demonstrated that those on the Histalean slimming pill lost 7 times more weight than those on the placebo.  What is more, no significant side effects were picked up and we know from experience that Betahistine has a very good safety profile.  Currently all of the centrally acting weight loss drugs can have very serious side effects which make them unsuitable for a number of people. 

It would appear that Histalean works better for women rather than for men and it also seemed to work better for those who are 50 or under.

This drug is not available to prescribe for weight loss at the moment but as soon as we have some news on this, we will publish it here.  The recent trial was only Phase II so it has a way to go before the authorities will give it a license for this purpose.

We have written before about the melanocortin system which is part of our central nervous system and has been demonstrated to regulate food intake.  A new study by scientists at the University of Cincinnati suggests that this melanocortin system can also act as a remote control from the brain, giving instructions as to the metabolism and storage of fat around the body.

Tests on rodents have demonstrated that when the system is activated (either genetically or pharmacologically), fat is metabolised.  When the system is deactivated, there is an increase in fat accumulation.

This discovery could be a breakthrough in developing a new generation of slimming pills which targets the melanocortin system as a means by which weight can be controlled.  The research is still in the early stages but studies of humans with a genetic variation in the melanocortin system which causes an accumulation of fat seems to confirm the observations made in the experiments on the rodents in the experiments.

Scientists at Pennsylvania State University College of Medicine have just published a paper which has revealed some very interesting facts that could potentially lead to a ground-breaking treatment for obesity.  The research team carried out experiments on mice by disrupting an enzyme which is involved in the metabolism of amino acids.  This led to continuous cycle of protein synthesis and breakdown, which is believed to have been caused by the elevated blood levels of an amino acid called leucine.

The mice which lacked the enzyme BCATm saw a ten fold rise in blood leucine.  As a result of the enzyme deficiency, the mice ate more food than normal mice but were slimmer.  This was deduced to have been caused by the energy drain caused by the protein turnover.

It would not be possible to get this effect simply by introducing dietary leucine as this stimulates protein synthesis but disrupts the breakdown.  Any solution for humans would have to be via a pharmacological product which would be able to manipulate the activity of the BCATm enzyme.  This truly would be the wonder pill that dieters have been looking for as it would mean that they could eat to their heart’s content and burn off all the energy through an increased metabolism.  Any potential solution in this field is decades away however!

GW Pharmaceutical of the UK, which is fast becoming the world leader in research into the therapeutic benefits of cannabis, has announced that it is to begin Phase I trials of a new weight loss drug which is derived from cannabis.  Cannabis contains tetrahydrocannabinol (THC) which activates the CB1 and CB2 receptors to boost appetite.  However, another substance known as tetrahydrocannabivarin (THCV) is also present and this has the opposite effect.  If the THCV is isolated, this can be used as the basis for a medication which may be able to switch off the appetite. Clearly, this may have serious undesirable side effects so the drug will have to go through years of thorough tests before it is available to prescribe.  As soon as we have some more information, we will post it here.

Scientists have developed a new slimming pill that appears to trick the body into burning fat in a similar way as happens when we exercise.  The drug is many years away from being available to prescribe but it has successfully been tested on mice.  If the drug is confirmed as being safe enough to be tested on humans, it could herald a radical way to treat overweight and obese people.  At the moment, the only medications available to prescribe for patients who are overweight are either lipase inhibitors, which partially prevent the absorption of fats by the body, or drugs which influence appetite by a variety of means.

The drug has been developed by Dr Ronald Evans who has spent many years studying obesity, its causes and its consequences.  The active ingredient in the drug is a synthetic form of fat which appears to work by flicking a master switch within the cells which regulates the laying down or burning of fat.

Previous studies by Dr Evans have focussed on genetic engineering to create a strain of mice that is entirely resistant to weight gain and has a physical endurance twice that of ordinary mice.  As the genetic engineering of the mice had to take place pre-birth, there was no prospect of this having any direct human application as such genetic modification would not be acceptable.  This new discovery, which involves chemical metabolic engineering, is a very exiting development which could eventually revolutionise the lives of millions of people by reducing fatty tissue, lowering blood lipid levels, cutting blood glucose levels and reducing resistance to insulin, thus limiting the risks of heart disease and diabetes.

The US drug development company, Orexigen, has recently announced successful Phase II results for the trial of Excalia, its new weight loss medication. Patients treated over a 48 week period managed to lose an average of 12 per cent. of their body weight. The medication, which may not be available to be prescribed for around 4 years, uses two currently approved medications to target a specific reciprocally paired group of hypothalamic neurons to trick the hypothalamus (the area of the brain which regulates appetite, energy output and body weight) into keeping the metabolism running fast at the point where the body would normally make a compensatory adjustment for the effects of a reduction in body weight.

The medication contains Bupropion and Zonasimide, two currently approved medications used for the purposes of facilitating smoking cessation and the treatment of epilepsy. By using these two different drugs, Excalia offsets the body’s natural compensatory pathways and appears to help slimmers avoid hitting the weight loss plateau that they normally reach a few weeks into their new diet and exercise regime.

The results were recently announced at a conference organised by the North American Association for the Study of Obesity. The company behind the drug is now recruiting patients for a larger scale clinical trial prior to filing for approval with the various drug licensing authorities around the world.