Gene therapy finally gets its day!

DNA vaccine and Gene therapy techniques are si...

DNA vaccine and Gene therapy techniques are similar. (Photo credit: Wikipedia)

It is finally real.  One very specific form of gene therapy has been approved by the European drug authorities.  Actually, China has allowed some forms of gene therapy since 2003, but regulatory authority in Chinese Healthcare is not as rigorous as other countries.

What exactly constitutes gene therapy.  It is a form of treatment for any disease in which a defective gene is replaced by a functional gene through a very a specific protocol.  Simply injecting genes or using gold particle coated with gene(s) (units of DNA which code for a protein) is not enough.  Genes must be delivered into cells through certain vehicles before they can work properly.  Viruses make excellent carriers of genes because of their unique properties of 1) infecting cells and 2) getting gene products to be converted into protein products in an efficient manner.

The US and other countries with active medical research capabilities have been certainly keen to adopt gene therapy in the past.  However, as of date, there are currently NO gene therapy approved protocols/nor products in the US.  Why?  In 2000-2001 the entire human genome was sequenced and we technically at least know all the genes that humans have.  So, the issue of the gene itself is solved (theoretically).  The problem is in the delivery.  How do we get cells (and the right cells in fact) to take up the genes and most importantly convert the gene into a useful product?

That is where viruses come in.  The most useful and somewhat safe viral system developed so far is something called the adenovirus.  This virus will infect human cells and allow the inserted gene to be converted into useful protein product.  Also importantly, the virus itself does not insert the gene into the human genome.  In this way the new gene does not disrupt the existing genes or DNA material that is inside the cell.

Sounds good.  So what the problem?  Well all viruses are pathogens.  That means that part of the definition of a virus is that it infects human and has the potential to cause an infection.  Secondly, even if it has been modified extensively, it is still a virus and thus a foreign entity or organism.  One fundamental tenant of the human immune system is that foreign proteins or entities are immunoreactive.  Thus, the human immune system can mount an aggressive  response.  That response is normal, but can actually kill the patient if strong enough.  In fact, that is exactly what happened in a very well publicized gene therapy trial for a teenage boy with a very rare disease (ornithine transcarbamylase deficiency) in 1999, who was killed after mounting a huge immune response against the viral carrier of the gene being replaced.  There have been a number of other accidents and failures to various gene therapy trials and the US regulatory authorities have been extremely cautious to grant approval of any new forms of gene therapy.

There are over 2000 different types of diseases which are potentially treatable with gene therapy.   Generally any deficiency in which a single gene is responsible can be treated with gene therapy.  All one technically has to do is make sure that the cell type which carries and produced the defective gene (like the gene responsible for the disease cystic fibrosis) and use gene therapy with a corrected version of the gene that is targeted to that cell using some kind of modified virus.  The gene needs to be produced over a long time in order to be effective as a treatment.  In the case of this newly approved gene therapy by the company called uniQure Glybera allows for the expression of the new gene that codes for a lipid processing enzyme that is deficient in the patient receiving the treatment.  The gene is introduced into the muscle tissue with an adenoviral associated virus (AAV).  As the virus does not insert the gene into the human genome itself the gene only lasts in the nucleus of the cells for as long as 12 weeks and seems to minimize the diseases for almost two years.  This new therapy relied on a AAV that has been modified to be non-pathogenic, thus not causing disease.  So, the parts of the virus that causes disease has been removed, the the parts that allows the virus to act like the virus has been kept (e.g. the viral coat proteins).  Only one case of fever (often a result of immune reaction) has been reported so far, thus this new viral vector may indeed hide itself from recognition by the immune system.

So, finally gene therapy gets its share of the limelight.  Generally, it takes one successful trial of a certain drug class (in this case gene therapy using AAV) to get other agencies to approve that therapy or to get the same agency to approve of use of that therapy in different disease.  In clinical trials at the moment is this type of gene therapy for Parkinson’s disease and others.  So, who knows this approval for this one disease may point the way to more approval for other countries and other diseases where single gene replacement is curative.

Thank you and please do support me by going to my web page…

Dr. C

Cancer treatments: traditional or not?

Logo of the Natural Products Association.

Image via Wikipedia

There seems to be a battle between those who passionately believe in traditional (evidence based) medical treatment and those who believe in non traditional (less evidence and sometimes no science-based) treatments.  Usually people are polarized one way or the other.  I would love to get a nice dialogue with folks who support one or the other and what the reasons are.  So let me start off by getting some of the terms spelled out and trying to categorize various types of treatments.

Pharmaceutical versus naturaceuticals:  The former is chemical based products designed and manufactured by pharmaceutical companies while the later is non-chemical based natural products (of course they can be chemical in principal, but not made synthetically) or extracts from natural products (such as seaweed, plants, oils, etc.). .

Traditional versus non-traditional (alternative medicine).  This is the western defined definition…traditional refers to surgery, radiation and chemotherapy while non traditional refers to things outside of this.  Traditional methods requires clinicians while non traditional may not.  Examples of non traditional treatment include vitamin C therapy, coffee enema, vegetable soups, etc.

Western versus Eastern medicine:  This usually refers to drugs and treatments designed to be used in modern health care and include drugs dispensed by trained cancer doctors while the later refers to things such as traditional chinese medicine, indian healing and traditional indian herbs, etc.  These might be dispensed by trained TCM practitioners but often given by parents and relatives of patients.  Some of these have many years of experience behind them but often have limited scientific studies behind them.

There are many other classes of treatment that do not have such nice and neat categories.  For example, I have a colleague who promotes holistic healing using energy (eg. from ones own self or from other sources).  Others believe that psychotherapy can help and some fo the techniques used include hypnosis.  Others belive that specific diets can starve cancer cells while normal cells grow well.  I have another colleague who calls himself Doc (not to be confused with Dr.) who uses a technique that analyzes hair samples and helps to identify (again using some interesting energy source) the cancer a person has but more importantly the source of the illness (e.g he belive that cancer is a result of other imbalances of the body).  He then embarks on a treatment plant (diet and natural products and alignment techniques) that corrects the underlying deficiency in the body that cures the patient.  There are many other types of proposed therapies and this only scratches the surface.  I would love to hear from you…the reader as to any treatments that you know about, swear works, or have suspicion about.

Let me finish by discussing some things that people tend to criticise about these types of therapies.  First of all major criticisms about modern therapies such as pharmaceutical based drugs and treatments include the following: 1) They are too expensive, 2) They don’t work- well they only target the cancer cell but not the underlying conditions that made the cancer grow in the first place, 3) They are not natural and thus inherently toxic, 4) Drug companies are in cahoots with Doctors and hospitals to milk the customer (the cancer patient) for as much money as possible so these companies can get larger and richer and 5) These companies spend so much on making these drugs (hundreds of millions) that many of these drugs can’t fail and the investment is too big and thus the claims for their effectiveness are exaggerated.  Common criticisms of other therapies include: 1) They are not tested well and have almost no scientific or clinical evidence for efficacy, 2) People who say they work base their assumptions on the one or two people who claim that they work but ignore the hundreds of people who they don’t know who had witnessed no recovery using these methods, 3) The few people who say these methods work could have gotten better for reasons we don’t know, 4) Some of the natural products that people take can actually be toxic in large amounts (especially for the liver or kidney), 5) Like pharmaceutical companies, companies that sell these so-called natural products for cancer treatment are also very biased, hide negative data, and try to sell inexpensive natural products at high prices to make a profit and have no real care for the patient. 

Despite how you feel there are likely to be real pros and cons for any type of treatments that you use if you have cancer.  No one is likely to be able to provide you with the miracle cure.  The comfort level and the background fo the patient is always going to play an important role and education can never hurt.  So, please do comment on this and let me know what you think!  Would love to see an active discussion going?  What do you favor or disfavor and why?  Can you challenge the status quo?  Do you have stories to share of how you may have changed your views about treatments?

Thanks for reading….. Dr. C

Cancer made Simple




cancer chemoptherapy

...of course, this was prior to the actual zap...

Image via Wikipedia


So, let’s talk about cancer therapy for a moment.  The major forms of therapy include Surgery, Radiation Therapy, Chemotherapy and targeted therapy.  Of course, surgery will be performed if it can be to remove the cancer (e.g. the tumor).  If the cancer is more advanced, than surgery alone will rarely help so one adds radiation to help with the more advanced forms of therapy.  May times radiation may not work so many tumors do respond to chemotherapy (drugs used to kill cancer cells) treatment.  The last form is more recent and is under intense research, but is used when advanced information is known about the biology or molecular biology of the tumor…it is a more specific and specialized form of therapy that can improve the life of some cancer patients.  The whole goal of cancer treatment is to remove or kill off the tumor if possible and if not help the patient to live as long as possible…to extend their life and to make life less painful if possible.  Please do ask me more questions and do come and visit my web page often! 

Dr Charles