24 mei: bron: o.a. virtual trials

DCA - Dichloroacetate zou tumorgroei remmen bij 5 patienten met een hersentumor glioblastoma. Dit melden onderzoekers aan de universiteit van Alberda in Canada. Toch is er ook kritiek op deze studie, vooral omdat niet duidelijk is of de patienten ook iets anders bij DCA hebben gebruikt (bv. Temodal) en wellicht de remming ook daardoor veroorzaakt zou kunnen worden. We hebben onderstaand citaten uit twee verschillende meningen over deze studie met DCA geplaatst en gevraagd aan een arts of hij dit voor ons wil vertalen c.q. becommentarieren. Wordt vervolgd dus. Hier alvast enkele citaten uit het positieve bericht over DCA bij 5 patienten met een hersentumor maar lees ook kritiek op de studie enz. van een prof. arts en wetenschapper op zijn blog: http://scienceblogs.com/terrasig/2010/05/dichloroacetate_dca_brain_canc.php?utm_source=networkbanner&utm_medium=link. Enkele citaten daarvan staan  onder citaten uit positieve bericht:

DCA research on brain cancer

May 12, 2010

Medical Researchers at the University of Alberta reported today evidence that the orphan generic drug Dichloroacetate (DCA) may hold promise as potential therapy for perhaps the deadliest of all human cancers: a form of brain cancer called glioblastoma. The report is published at the journal Science Translational Medicine, a journal of the American Association of the Advancement of Science.

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By extracting glioblastomas from 49 patients over a period of 2 years and studying them within minutes of removal in the operating room, the team showed that tumors respond to DCA by changing their metabolism. Then, the team treated 5 patients with advanced and secured tissues before and after the DCA therapy. By comparing the two, the team showed that DCA works in these tumors exactly as was predicted by test tube experiments. This is very important because often the results in non-human models tested in the lab do not agree with the results in patients. In addition, the team showed that DCA has anti-cancer effects by altering the metabolism of glioblastoma cancer stem cells, the cells thought responsible for the recurrences of cancer.

In the 5 patients tested, the drug took 3 months to reach blood levels high enough to alter the tumor's metabolism. At those levels, there were no significant adverse effects. However, at some of the higher doses tested, DCA caused nerve malfunction, i.e. numbing of toes and fingers. Importantly, in some patients there was also evidence for clinical benefit, with the tumors either regressing in size or not growing further during the 18 month study.

No conclusions can be made on whether the drug is safe or effective in patients with this form of brain cancer, due to the limited number of patients tested by the study's leads Drs Michelakis and Petruk. Researchers emphasize that use of DCA by patients or physicians, supplied from for-profit sources or without close clinical observation by experienced medical teams in the setting of research trials, is not only inappropriate but may also be dangerous. The U of A results are encouraging and support the need for larger clinical trials with DCA. This work is also one of the first in humans to support the emerging idea that altering the metabolism of tumors is a new direction in the treatment of cancer, Michelakis and Petruk said.

The research team hopes to secure additional funding to continue the ongoing trials with DCA at the University of Alberta. Further studies would include more patients with , and test the combination of DCA and standard chemotherapies, eventually including patients from other academic health sciences centres......

More information: The report appears today at the journal's web site http://www.sciencemag.org/

Provided by University of Alberta

Bron: Terra Sigillata, een blog van prof. arts onder deze nickname

Dichloroacetate not yet an effective treatment for aggressive brain cancer

.....The glycolytic pathway has become of renewed interest in cancer. Why? Because some but not all cancer cells differ from normal cells by using the inefficient production of ATP by glycolysis regardless of the amount of oxygen that's around. You'll hear the term "Warburg effect" used to describe this phenomenon because biochemist Otto Warburg published a famous 1956 paper in the journal, Science, suggesting that the origin of cancer lies in the ability of cancer cells to shift metabolism to glycolysis.

......

At present, there are a few chemicals known to inhibit glycolysis that resemble some of the intermediates in the process but require extremely high concentrations. One is called 3-bromopyruvate - as I wrote here in 2007, this chemical inhibits both glycolysis and oxidative phosphorylation so it would have to be injected directly into the artery that feeds the cancerous tumor. The other chemical is dichloroacetate (DCA).

DCA has been around for a long time and has been used in people with inherited diseases of mitochondrial metabolism. In 2007, a group at the University of Alberta led by cardiologist Evangelos Michelakis demonstrated that very high doses of DCA can slow the progression of human tumor cells grown in immunocompromised rats. The response to this story was unbelievable with internet marketers popping up to sell the simple chemical and conspiracy theorists saying that because DCA was cheap and not patentable, no drug company would ever develop it, it was being kept a secret, and so. In truth, the work was in very, very early stages.

This didn't stop hopeful patients from seeking out DCA sellers even though DCA can be contaminated with other related substances that are far more toxic. And in the most egregious case among these DCA purveyors, an Edmonton man who purported to sell DCA online was recently arrested in Phoenix and pleaded guilty to five cases of wire fraud - not because he was selling DCA but rather a white powder comprised of some combination of sucrose, lactose, dextran, and starch.

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This week, the Michelakis group has published a follow-up paper in Science Translational Research that includes laboratory experiments with cell lines isolated from cancer of 49 volunteers and a phase I trial of DCA in five patients with advanced glioblastoma who were also receiving a standard anticancer drug temozolomide (Temodar®) and radiation therapy. Keep in mind that the purpose of a phase I trial is not to determine a drug's effectiveness but rather its dosing and side effect profile. This is important because DCA has never been systematically studied in patients with cancer. I have not seen the paper because my institution does not receive the journal or have electronic access. However, press reports are noting that of the four patients surviving out of the starting five, three experienced reductions in the size of their tumors.

However, we don't know if these changes were due to DCA or the other treatments the patients were also receiving - this information is not included in most reports I have read.

Enz........Lees ook artikel uit Edmonton Journal


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