Support : eNewsletters : Eye on Innovation : Issue 4, September 2012

Cancer vaccines: Optimism for the future?

When Roswell Park Cancer Institute announced a new trial of an experimental cancer vaccine in early 2012, 5,000 people watched the event on the Internet, 4,000 called or emailed in the following days and nearly 1,000 people posted comments on Twitter — all this for a small study that would enroll only 18 participants to gauge safety.
Source: The Buffalo News in Global Reporter

This intense interest reflects the major re-emergence of an idea that has intrigued medical scientists for more than a century — using the body's natural ability to defend itself against disease-causing organisms, the immune system, to treat and prevent cancer.

Whether it's a family member, a friend, a colleague, few, if any, have not been affected in some way by cancer. This deadly disease kills millions worldwide, and despite medical breakthroughs to treat or prevent other diseases, cancer is still the second highest killer. Governments, the private sector and university medical centers have spent millions of dollars for years, but it has not decreased the numbers of those getting cancer or dying from it. However, no one has given up. In fact, the cancer vaccine field has grown rapidly over the past decade. Researchers have overcome numerous challenges and more vaccines are poised to enter the market.

This issue of Eye on Innovation explores innovations for treating cancer that may have the potential to curb and treat this killer. Drawing upon Dialog's extensive collection of science, technology and medical (STM) databases whose sources span the globe, its conference papers, business and news sources and patents, we'll look at novel vaccine discoveries that just may provide new treatments for those afflicted with cancer.

How do vaccines work on cancer cells?
Cancer vaccines are different from how we traditionally think of vaccination. They are not used to prevent cancer from occurring; they are given to patients who are already suffering from cancer to help their bodies fight off the disease rather than to prevent the disease in the first place.

Cancer develops because it manages to escape the immune system. Cancer cells usually evade a patient's immune system because they are not recognized as being a threat. While the immune system usually attacks foreign cells such as bacteria, tumors are formed of the patient's own cells that have malfunctioned. Cancer cells contain high levels of MUC1, and it is thought that this protein helps tumors grow. When a vaccinated patient's immune system encounters cancer cells, however, the far larger concentration of MUC1 causes it to attack and kill the tumor.

Cancer-fighting vaccines approved by FDA
Research into the use of cancer vaccines to activate the immune system to treat cancer has increased significantly recently. With FDA approval of quadrivalent (Gardasil) and bivalent (Cervarix) to prevent cervical cancer, coupled with FDA approval of sipuleucil-T (Provenge) to treat prostate cancer and Yervoy for melanoma, cancer vaccines have made major headlines over the last few years.

A search for “cancer vaccine” yields a list of 1,136 ongoing trials for vaccines that treat a variety of cancers, including lung cancer, breast cancer, pancreatic cancer, prostate cancer, brain cancer and melanoma, among others. Many are in phase 1 and phase 2, but some are as far along as phase 3. For example, there are currently more than 25 clinical vaccine trials specific to breast cancer treatment, many of which target breast cancer cells with a specific protein on them, as in the case for HER-2. Eventually, treatments may be individualized based on the unique set of molecular targets produced by the patient's tumor. Targeted cancer therapies also promise to be more selective for cancer cells than normal cells, thus harming fewer normal cells, reducing side effects, and improving quality of life. A chief limitation is the potential for cells to develop resistance to therapies. Thus, scientists are also looking into whether targeted therapies may work best in combination, either with other targeted therapies or with more traditional methods.

Sources: Expert Review of Vaccines, International European Journal of Cancer Prevention, Vaccine, Drugs and Therapy Perspectives, Neurosurgery Clinics of North America from MEDLINE^®, Embase^®, Gale Group Health & Wellness Database^SM

No magic bullet
Using the immune system to combat cancer has its advantages and challenges.

• The immune system can selectively target and kill infected cells without harming normal cells. However, tumor cells arise from normal cells and resemble them. A cancer vaccine must figure out how to educate the immune system to recognize the tumor cells and either remove them or keep them in check.
• The immune system also develops a memory for these microbes and guards against the same invaders infecting the body in the future. However, to be truly safe and effective, a vaccine must also bring about a long-term "memory" for the tumor cells it is designed to target and accomplish this without producing autoimmunity, a condition in which the immune system attacks the normal cells it is supposed to protect.
• An attractive quality of a therapeutic cancer vaccine is that it is less toxic compared with other treatments for cancer, particularly chemotherapy. Whereas adverse effects of chemotherapy, such as fatigue, nausea and vomiting, are common, adverse effects of a cancer vaccine are rarer and may include a flu-like symptom and possibly a rash or irritation at the point of injection. Moreover, the treatment timeframe of a cancer vaccine is also relatively short, another advantage to the patient. For example, the prostate cancer vaccine sipuleucel-T is given in three injections, two weeks apart. Thus, the treatment lasts only six or seven weeks compared to the 30 weeks needed for 10 cycles of docetaxel (Taxotere), the traditional chemotherapy for prostate cancer. However, the cost of vaccine treatment can be very expensive, one cycle dosage averaging $100,000, with modest benefit and limited use to patients with advanced cancer. So, the vaccines are rarely prescribed.

Sources: Journal of Immunotherapy, Esophagus from MEDLINE, Embase; The Financial Times Limited, The Buffalo News from Dialog Global Reporter, PR Newswire from Gale Group PROMT^®

Worldwide stories offer hope
Case 1. In Africa, which has a population of 267.9 million women aged 15 years and older at risk of developing cervical cancer, approximately 80,000 women are known to be diagnosed with cervical cancer each year, and just over 60,000 women die from the disease, the highest number of cervical cancer deaths in the world. For example, in Uganda, cervical cancer is the most frequent cancer diagnosed among women and incidence rates of the disease in the country are about three times the global average. An estimated 3,500 women in Uganda are diagnosed with cervical cancer each year. In an effort to combat the high rate of this disease, the Ministry of Health (MoH) in Uganda, supported by a donation of 460,000 doses of Gardasil from Merck over a two-year period, will vaccinate approximately 140,000 eligible girls in 12 districts throughout the country. The program represents the first phase of Uganda's national plan for human papillomavirus (HPV) vaccination.

Case 2. The drug ImMucin, a vaccine designed to train cancer patients' own bodies to seek out and destroy tumor cells, has been produced by Vaxil BioTherapeutics. Results from early clinical trials have shown the vaccine can trigger an immune response in patients and reduce levels of disease.

ImMucin has entered Phase III clinical trials at Jerusalem's Hadassah University Medical Center and will be tested on hundreds to thousands of patients. As a therapeutic vaccine, it will be given to patients who are already suffering from cancer. The drug is designed to stimulate the patient's immune system to selectively target tumor cells and help their bodies fight off the disease. Scientists hope to prove the drug effective against a range of different cancers to combat small tumors if they are detected early enough or to help prevent the return and spread of the disease in patients who have undergone other forms of treatment such as surgery.

If the vaccine passes this phase, the drug will go to the appropriate regulatory authorities in countries around the world. After passing regulatory review, the drug would be able to enter the drug market.

Sources: International Journal of Cancer, New Vision from MEDLINE, M2 Presswire, NA from Gale Group Health & Wellness Database

The intellectual property advantage
In addition to licensing and partnerships, a key to building value in a vaccine product portfolio is maintaining the strength of intellectual property. Some companies already have a headstart.

• Immunovaccine's intellectual property rights covering its vaccine delivery technology includes five patent families, issued in the United States, Europe, Japan and Australia. In February 2012, the company secured a new U.S. Patent specific to the DPX-0907 therapeutic cancer vaccine. The firm plans to expand its patent coverage with an additional 33 patents pending in eleven jurisdictions.
• Galena Biopharma, a biotechnology company focused on developing innovative, targeted oncology treatments, has announced the issuance of a patent from the Japan Patent Office for a Composition of Matter and Method of Treatment. The patent supports Galena's strategy to develop targeted peptide cancer vaccines to prevent or delay cancer recurrence in early state patients. The Japanese patent provides exclusivity in the country until 2022, with additional worldwide patent filings pending.
• Oncbiomune, a biotechnology company specializing in innovative cancer treatment, has proprietary rights to a breast cancer vaccine (patent #5,478,556) and prostate cancer vaccine (patent pending), as well as a (patent pending) process for the growth of cancer tumor cells.

Sources: Recent patents on anti-cancer drug discovery from MEDLINE; Derwent World Patents Index^®

Next steps?
Even with new advancements to use vaccines for treating cancer, something seems to be clear for at least the near future—there may be no one formula for fighting many cancers. Experts agree that more work must be done to understand exactly how the immune system functions against cancer so that optimal vaccines can be created. Although it appears that vaccines will definitely play a role, they alone are not the single wave of the future for cancer treatment. To develop more efficient and effective cancer vaccines, it will be necessary to design new clinical trials combining cancer vaccines with chemotherapy, radiotherapy and drugs that target those factors responsible for suppressing immune cells.

Another task is to test these vaccines in patients with earlier stage cancers, as accompanying adjuvant treatment. And, an ultimate goal of cancer vaccines is to use them to prevent cancers, much like we use the HPV vaccine to reduce cervical cancer in women, and the hepatitis B vaccine to prevent liver cancer. The prevention of other, nonviral cancers is the hope for the future. If a therapy can prevent them, there may be an even greater benefit than suspected to use vaccines in combination with other treatments. Nonetheless, with cancer vaccines now on the market, and the numbers of clinical trials and interest in vaccines increasing, the cancer vaccine market is likely to witness a significant growth in the next few years.

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