Gene therapy can be simply defined as a therapeutic technique which alters the genetic constituency of a cell in order to treat a specific disease. The concept was first introduced as early as 1972, although it was only in the year1990 that the FDA granted permission to conduct the first gene therapy experiment in the US on a girl named Ashanthi De Silva.
At four years of age, young Ashanthi was suffering from an inherited and fatal immune disorder known as ADA deficiency, which made her vulnerable to even the mildest of infection. However, after undergoing gene therapy and other treatment methods, Ashanthi was able to beat all odds and survive with the potential to be completely cured in the future. Although she is living healthily, researchers are still skeptical about what made Ashanthi to recover, and such skepticism does pose the question, is gene therapy a scientific dream or reality?
Many researchers agree that gene therapy holds huge promise as a medical treatment. In fact, it is one of the most actively researched areas in the genetic field. However, almost four decades after its conceptualization, the scientific community is still searching for safe and effective gene therapies which could benefit the large number of patients who are living in hope of receiving a miracle cure.
In order to understand the challenges faced by gene therapy, it is necessary to first understand how gene therapy works. In the human cell, the genetic material known as the DNA contributes toward formation and the functioning of tissues and organs. A defect in the genetic sequence may therefore alter these processes and could lead to disease states as was described in Ashanthi’s case. If such defective genes can be recognized, it is theoretically possible to alter these defective genes toward preventing or curing the associated disease states. In order to do this, doctors have to extract the defective genetic material from the patients’ cells and introduce the same to a "vector" (usually a virus), which contains the healthy genetic sequences or the genes. The combination could then be introduced back to the patient and replace the defective genetic material by allowing the cells to uptake the healthy sequences. Although the process seems to be straightforward, there can be many flaws at various stages.
One of the main challenges faced by scientists is the reliability of the delivery system, which should carry the healthy genes to their target location. At the same time, there is a possibility that the newly introduced sequence may alter the genetic sequences of healthy cells that may thereafter perform abnormally. In addition, if the introduced gene is inserted at a wrong location in the DNA sequence, it may give rise to a different disease or sometimes even cause cancerous tumors. Thus, scientists have to be absolutely sure that, by introducing genetic material, they do not cause more harm than good to the already suffering patient.
However, there are promising signs emerging in the field of gene therapy. In this regard, the five-year survival data of the cancer patients being treated with Gendicine can be highlighted. Being the first commercially approved gene therapy, Gendicine has shown that people who have been treated survive beyond their non-treated counterparts, although much controversy exists with regard to its research design, as well as on how the clinical trial was performed. In any event, Gendicine and related research have proved that gene therapy can become a commercial reality, although market challenges such as cost could make it the second line of treatment rather than the main treatment modality.
In summary, the scientific community still believes that gene therapy could be the mainstay of treatment for many diseases in the near future. However, experience shows that there are no shortcuts when it comes to introducing a treatment modality such as gene therapy. Thus, while accepting that gene therapy can play a big role in the future medical practice, it should also be said that hopes of miracle drugs in the near future might not be a reality, after all.