Discovery Signals Opportunity for Prostate Cancer Drug Companies

Prostate cancer is the most common cancer among men, and until now, treatment has been largely limited to radiation and hormone therapy, with many life science companies focused on better screening and early detection over drug development.

But last week, scientists in the United Kingdom announced that they’ve found the likely antecedent of prostate cancer, meaning that there is new hope that drug therapies that target stem cells may lead to more effective therapies that will work against the root cause of the disease.

Findings published this week in Nature Communications by scientists at the University of York reveal the existence of a cancer-inducing DNA realignment in stem cells taken from human prostate cancers.

Professor Norman Maitland, director of the YCR Cancer Research Unit, and his team in the university’s biology department, was the first to isolate prostate cancer stem cells in 2005 and the first to discover last year a link with low vitamin A as a leading cause of prostate cancer.

While other cancer cells can be killed by current therapies, stem cells are able to evade their effects, resulting in cancer recurrence. The team has since been exploring the exact molecular properties that allow these cells to spread, survive and resist aggressive treatments such as radiation and chemotherapy.

“This discovery marks a fundamental shift in our understanding of how solid cancers start. It is believed that ‘root’ cancer cells arise from healthy stem cells going wrong – for example certain controls can be turned off which allow the cells to keep growing and invade surrounding tissue,” said Prof. Maitland in a statement published by the university.

“In blood cancers such as leukemia, DNA is rearranged during an event known as chromosomal translocation, which results in a mutant protein that drives cancer progression. Although similar rearrangements have recently been discovered in solid cancers, until now, they have not been considered as stem cell functions. Our work has challenged this idea.”

Professor Maitland’s team has found these genetic accidents in prostate cancer stem cells and has shown that they result in a specific cancer-associated gene within the cells called ERG being inappropriately activated.

It is believed that this activation triggers the stem cells to renew more often.

“The cells become selfish by surviving outside normal controls that exist in the prostate and thrive at the expense of their neighbors, ensuring that the genetic accident becomes permanent and passed from generation to generation. This process appears to be essential for the initiation of prostate cancer,” he wrote.

The findings hold promise for the development of new therapies which specifically target the identified protein, killing the stem cells that remain after chemotherapy while leaving healthy cells untouched.

Some companies that are doing leading work in detection and therapies for prostate cancer include:

DiagnoCure (TSX:CUR) of Quebec City develops and commercializes cancer diagnostic tests. Earlier this month in Milan, at the International Conference on Prostate Cancer Prevention, DiagnoCure’s PCA3 product, a biomarker for detection of prostate cancer, was praised by scientists for its clinical utility.

The company is banking on biomarkers as a better detection of early onset of prostate cancer over the present standard screening method using PSA (prostate specific antigen) in the blood combined with a digital rectal examination. PCA3 looks for genetic markers highly specific to prostate cancer found in urine. DiagnoCure’s proprietary molecular biomarker, called the Hologic Gen‐Probe’s PROGENSA® PCA3 test, is commercialized in Europe under CE mark and is approved for commercialization in Canada and the United States.

A prostate drug that has generated a lot of attention is Provenge which is billed by Seattle-based biotechnology company Dendreon (NASDAQ:DNDN) as the only personalized treatment clinically proven to help extend life in certain men with advanced prostate cancer.

Dendreon Corporation is a biotechnology company whose mission is to target cancer using its specialty in antigen identification, engineering and cell processing to produce active cellular immunotherapy (ACI) product candidates designed to stimulate an immune response in a variety of tumor types. Dendreon’s first product, Provenge (sipuleucel-T), was approved by the FDA in 2010.

In an article last year, however, Reuters raised concerns about how Dendreon’s data used to obtain the FDA approval for Provenge was artificially inflated.

Provenge is an immunotherapy that takes immune cells from men diagnosed with prostate cancer and reprograms it to attack advanced prostate cancer. Patients give their cells at a cell collection center three days before each therapy session. The immune system is stimulated by a protein that functions as an antigen — a substance that causes the body to react with an immune response. Activating that antigen triggers the patient’s immune cells against prostate cancer to help fight the disease.

The treatment is pricy — it costs an estimated $93,000 for the therapy which is picked up by Medicare in the US. The reason why Provenge costs so much is because it is made specifically for each patient using cells from the patient’s own immune system so it cannot be warehoused like other drugs and requires specialized manufacturing facilities.

Earlier this month, the company announced it was settling a class action lawsuit brought against the biotech by a group of investors who purchased Dendreon’s common stock over a 16-month period between 2010 and 2011. The investors claimed three current and former officers of the company made misleading or false information about the company. The company’s insurers are paying $38-million of the $40-million settlement.

Securities Disclosure: I, Andrew Topf, hold no direct investment interest in any company mentioned in this article. 

Related reading: 

Mutation Detection is Key to Developing Vaccines