Cancer drug discovery and development

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Oct 14, 2019
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Cancer drug discovery: FAQ

What is cancer?
Current cancer drugs
Drug discovery approaches
Innovations in cancer drug discovery

How does cancer work?

Cancer is the uncontrolled proliferation of cells in the body. Cancer cells can continue growing at a rate that exceeds that of healthy cells because they do not abide by the normal rules that control and limit cell division. As opposed to non-cancerous healthy cells, tumor cells do not mature into distinct cells, which is another factor as to why they can continue growth.  

As the cells continue proliferation, they can form solid tumors. Tumors remain benign until some of the cells break off and spread to other parts of the body – developing tumors in secondary locations also. This is the point at a benign cancer becomes malignant [1].

Why cancer research is important?

Cancer research, as with the research of any of the disease, ultimately aims to develop effective treatments, diagnostic tools and ways to prevent it. By understanding the underlying mechanisms at play in this group of diseases, researchers can work to both improve the current treatment options, as well as develop novel and innovative ways to treat the patients.

As with many other countries, cancer is a major contributor to disease and death. According to the Centers for Disease Control and Prevention (CDC) over 1.6 million cases of cancer diagnoses were reported in 2016 in the US [2].  More research and developments are constantly needed to help those affected by this disease.


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Current cancer drugs

Which drugs do cancer patients take?

The type of treatment options available for cancer patients depend on the type of cancer and how advanced it is. Some treatments aim to eradicate the cancer cells, whilst others accompany these to alleviate symptoms such as pain. Many cancer treatments plans use a combinatory approach, where they may use multiple types of therapeutic options to help overcome the disease. Common types of treatment include, chemotherapy, radiation and therapy but new ways to treat these diseases are being developed every day.

How do cancer drugs work?

Chemotherapy: Chemotherapy is one of the most common treatments given to cancer patients. With this, drugs are used to either kill the cancer cells or stop them from growing and reaching other parts of your body. It does this by specifically targeting rapidly dividing cells. Typically, many will work by damaging the DNA in the cells that inform them to keep diving – slowing their growth and killing the cells (and causing the tumors to shrink in the case of solid tumors) [3].

Radiation therapy At high doses, radiation can slow cancer cell growth and kill them, again, by damaging their DNA. Radiation can be administered either externally or internally. The machine for external treatment aims the radiation beams specifically at the area of the body where the cancer resides – for example it is currently used for breast cancer. Internally radiation therapy can be liquid or solid. Solid therapy works more locally than external options by placing a solid radiation source inside your body, in or close by to the tumor. Liquid radiation therapy on the other hand travels throughout the systemic system to target cancer cells [4]

Why are cancer drugs so expensive?

Whether a patient has to pay for the drug they need for their treatment depends on the country they live in. For example, in the UK many, if not most, of the cancer therapies are available on the NHS, meaning residents do not have to pay out of pocket for treatments. However, in countries like the US the process for paying for drugs becomes slightly more convoluted. Although some are covered by their insurance policies many still have to pay for treatment themselves.

However, to answer the question of why cancer drugs can be expensive, we may need to look at the process of creating and developing these drugs. Drug discovery is a lengthy and costly process; it can often take over 10 years and is estimated to cost US$2.6 billion to bring just one drug to market. However, I guess the question we have to ask is does this figure justify the prices set? A question that is constantly debated.

What are the side effects of cancer drugs?

Side effects of cancer include, hair loss, pain, nausea and fatigue, just to name a few.

Although chemotherapy works to specifically target rapidly dividing cells. Cancerous cells, just as healthy cells, need to divide to survive as part of their normal process. Hence, chemotherapy isn’t able to completely differentiate between healthy and cancerous cells, which is why healthy cells can be targeted and cause these additional side effects.

Cancer drugs without side effects? Click here to find out more

 


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Drug discovery approaches

Why is cancer drug discovery so difficult?

As with any drug discovery program, researchers typically work by identifying a target, for which they then develop and optimize a drug to target it. Since cancer does not describe just one disease but a whole group of diseases, discovery and success of one drug may not lead to the same outcome in another. Advances in research continues to show how heterogeneous and complex these diseases are.  

Some cancers are more difficult to treat than others, which can often be down to difficulties in diagnosis. For example, breast cancer patients when diagnosed early are more likely to respond well to treatment, as opposed diagnosis at a later stage. For esophageal cancer, a cancer that is notoriously difficult to treat, early detection is imperative for treatment. However, with very few visible symptoms and small size of the tumors, it can be very hard to diagnose.

Drug resistance is also a major contributing factor to the short-term success of many cancer drugs. In cases where resistance develops, cancer cells become immune to treatment and are able to continue their rapid growth and proliferation. Many factors can contribute to the development of resistance, such as genetic changes or tumor heterogeneity between different tumors and within the same tumors [5].

Who makes cancer drugs?

There are various companies who are working with cancer drug discovery. Of the most recent cancer drugs approved, some of these have been developed by [6]:

Company Drug  Indication Approved
Norvartis (Basel, Switzerland) PIQRAY® Breast cancer May 2019
Pfizer (NY, USA) TRAZIMERA™ Breast and gastric cancer March 2019
Genentech (CA, USA) HERCEPTIN HYLECTA™ Breast cancer February 2019
Bayer HealthCare Pharmaceuticals (NJ, USA) NUBEQA® Prostate cancer July 2019

Innovations in cancer drug discovery

How does cancer immunotherapy work?

Immunotherapy is a type of treatment that utilizes the body’s own natural defenses to combat a disease. In the case of cancer, it is being used kill cancer cells. As cancer cells are simply mutated versions of our own cells, our immune system does not recognize them as easily as it would a cell from an infection. As well as this, cancer cells have developed a range of ways to trick the immune system into believing they are healthy cells – allowing them to continue their rapid proliferation.

If therapeutics are developed to ‘boost’ the immune system, cancer patients could theoretically use their own immune system to recognize cancer cells and improve their ability of fighting them [7].

What is targeted cancer therapy?

These therapies work to target and act upon specific genes, proteins and cellular components known to be implicated in cancer development, growth and survival. This approach has the potential to treat cancer by focusing specifically on the changes that make them different from healthy cells, this includes their behavior, DNA and appearance [8].


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 Sources:

  1. What is cancer? https://www.cancer.gov/about-cancer/understanding/what-is-cancer (Accessed 19 September 2019)
  2. Leading Cancer Cases and Deaths, Male and Female, 2016. https://gis.cdc.gov/Cancer/USCS/DataViz.html (Accessed 20 September 2019)
  3. Cancer cells and chemotherapy. http://chemocare.com/chemotherapy/what-is-chemotherapy/cancer-cells-chemotherapy.aspx (Accessed 19 September 2019)
  4. Radiation Therapy to Treat Cancer. https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy (Accessed 19 September 2019)
  5. Housman G, Byler S, Heerboth S et al. Drug Resistance in Cancer: An Overview. Cancers. 6(3). 1769—1792. (2014)
  6. New Drug Approvals. https://www.drugs.com/newdrugs.html (Accessed 18 September 2019)
  7. Immunotherapy to Treat Cancer. https://www.cancer.gov/about-cancer/treatment/types/immunotherapy (Accessed 19 September 2019)
  8. What are targeted cancer drugs? https://www.cancerresearchuk.org/about-cancer/cancer-in-general/treatment/targeted-cancer-drugs/what-are-targeted-cancer-drugs (Accessed 19 September 2019)

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