Category: Health

Finding a cure for HIV infection; promise or reality?

(Note: all the sources listed in the “Balanced” section)

Anti-retroviral therapy (ART), or highly-active-antiretroviral
therapy (HAART), is effective in halting progression of HIV infection. However,
the HIV virus, despite of the treatment, remains hidden in the human body. In
2017, existing medications for the treatment of HIV infection such as Gilead’s
Genvoya and Merck’s Isentress had annual sales of $3.67 billion and $1.2 billion,
respectively. Notwithstanding their commercial success, these medicines do not
cure the disease. The HIV virus often remains hidden in the human body in
reservoirs such as dendritic cells, macrophages, and CD4⁺
lymphocytes. Since HIV was first detected in 1983, the medical community have
intensively searched for a cure for HIV infection.

The
Story of the Berlin Patient. In 2007, Timothy Ray Brown, an American studying in Berlin,
Germany, was treated with a hematopoietic stem cell transplant. Two years
earlier, Mr. Brown had been diagnosed with a type of blood cancer known as acute
myeloid leukemia (AML). Besides its cancer diagnosis, Timothy was infected with
the Human Immunodeficiency Virus (HIV). Dr. Gero Hütter, a German doctor from
the Charité Hospital, Berlin University of Medicine, performed the transplant. At
the time, Dr. Hütter had never treated an HIV patient before Timothy, but he
had learnt about a rare genetic mutation causing natural resistance to HIV
infection. Based on this information, Dr. Hütter found a stem-cell donor
carrying this specific mutation. He performed the transplant on Mr. Brown using
these mutated cells.

The procedure resulted in a surprising outcome as Timothy’s HIV
infection disappeared after the transplant. The HIV virus could not be detected
on his blood, not even with the most sensitive diagnostic techniques such
polymerase chain reaction (PCR) methods. Timothy Ray Brown was cured of his HIV
infection. He became famous in the medical community. Timothy is now known as
the Berlin patient (https://www.youtube.com/watch?v=f6DXqGZt_Fw). The story of the Berlin patient triggered significant interest in both academy and industry, setting off a golden rush to find a sterilizing cure for HIV infection. Timothy’s transplant treatment was done from a donor carrying a mutation in a gene known as CCR5, which happens to be the site of entry utilized by HIV virus to infect immune system cells (New England Journal of Medicine 2009, 360, 692-698). The CCR5 protein receptor is expressed on the surface of lymphocytes T, which are the predominant target cell for the virus. Two cell receptors, CD4⁺ and CCR5, are utilized by HIV to enter the cell. The virus cannot enter and infect cells with a defective CCR5 receptor. As a result, HIV cannot find a home, the patient’s viral load gradually decreases, and eventually the virus fizzles out. This is probably what transpired during Mr. Brown’ treatment procedure. The fact of the matter is that the virus became undetectable in Timothy’s body. He stopped taking any medication for HIV, although he continued to undergo treatment for his blood cancer. Since then, Timothy has remained HIV negative. He has been cured from his HIV infection.

Alzheimer’s; will an effective treatment emerge?

(Note: all the sources listed in the “Balanced” section)  

Alzheimer’s disease is the main cause of dementia, memory loss,
and cognitive decline in elderly patients. The illness’ symptoms start
gradually, but worsen quickly later on, severely affecting thinking and
behavior of patients. Alzheimer’s disease remains as one of the most difficult
challenges for the biotechnology and pharmaceutical industries. Undoubtedly,
the commercial opportunity for a “disease-modifying drug therapy” for
Alzheimer’s patients has the potential to become the largest blockbuster drug
in the history of both industries. Thus far, all attempts to develop such a
candidate medicine have resulted in clinical trial failures.

Cancer gene therapy – past, present & future

(Note: all the sources listed in the “Balanced” section) 

To the medical community, the premise of
replacing mutated genes with normal corresponding genes have been widely viewed
as a promising treatment for cancer. “Oncogenes” are genes known to promote
malignant tumor growth, whereas “tumor suppressor genes” have the opposite
function as they inhibit tumor formation. The scientific theory of replacing a
mutated tumor suppressor gene for its corresponding normal copy is robust, with
scientists, physicians and biotech entrepreneurs agreeing that the pursue of
gene therapy approaches for the treatment of cancer should become a common goal
(https://www.youtube.com/watch?v=2NVBsPfOtT8).

In spite of this enthusiasm, not all investors
are fully convinced, as some remain skeptical about the prospects for cancer
gene therapy.

Cancer vaccines; promise becomes reality?

(Note: all the sources listed in the “Balanced” section)

The premise of harnessing the power of a patient’s immune system
to kill cancer cells is more than 100 years old. In 1891, Dr. William Coley, a
surgeon affiliated with the Memorial Sloan Kettering in New York City,
developed an immunotherapy for the treatment of cancer based on bacterial
toxins. This was the first attempt to use a cancer vaccine. Today, Dr. Coley is
known as the “Father of Cancer Immunotherapy”.

The Birth of Cancer Vaccines – An Old Story Becomes New Again. After failing to save the life of an 18 years old woman with
sarcoma, a type of cancer, in the year 1891, Dr. Coley was affected deeply and
dedicated himself to find a cure for the disease. He found that sarcoma patients
concomitantly suffering from a skin bacterial infection known as erysipelas
(caused by group A streptococcus
bacteria), have undergone spontaneous regression of their cancers. Dr. Coley
thought that causing a bacterial infection could help combat cancer in these
patients. He injected the erysipelas germ into the tumor of a 35 years old man
suffering from head and neck cancer. The treatment worked. The first cancer
vaccine was born.    

In
Recent Years, Results in Human Clinical Trials with Cancer Vaccines Have Been
Disappointing. Despite of the robust rationale behind the use of cancer vaccines
for the treatment of cancer, the long history behind this medical hypothesis,
the search for the “Holy Grail” (a curative cancer vaccine) has been elusive. Over
the last twenty years, cancer vaccines have been a disappointing segment of the
biotechnology sector for investors. Despite of the innate appeal of the idea of
using cancer vaccines as an effective weapon against cancer, the results of
late stage human clinical trials have been discouraging to scientists,
entrepreneurs and investors.