ONS 2014: Using Viruses to Fight Cancer

Oncolytic viruses are receiving more attention these days as a form of cancer treatment, and have shown promise in clinical trials. These viruses are thought not only to cause direct destruction of the tumor cells, but also to stimulate a patient's immune response.

When we hear about viruses, we typically don't think of them as a form of cancer treatment. Oncolytic viruses are receiving more attention these days as an up-and-coming form of cancer treatment showing promise in clinical trials.

Cindi Bedell, RN, MSN, ANP-C, Ann Collins-Hattery, RN, MS, AOCN, ARNP, and Jeanne Jones, RN, MSN, presented a session, “Oncolytic Immunotherapy: Using Viruses in the War Against Cancer", at the 2014 Oncology Nursing Society (ONS) Annual Congress.

So why all the fuss over viruses?  Well, viruses have the ability to infect and kill cancer cells. As the infected cancer cells are destroyed by lysis, they release new infectious virus particles to help destroy the remaining tumor. Oncolytic viruses are thought not only to cause direct destruction of the tumor cells, but also to stimulate an immune response.

Different kinds of viruses may be used to help kill cancer cells: wild-type and genetically engineered. Wild-type viruses occur naturally and have relatively low pathogenicity. An example of this would be the herpes simplex virus (HSV). The HSV type-1 has the ability to infect and lyse cancer cells with minimal risk of causing disease-patients may experience a cold sore for example. A genetically engineered virus ablates virtually all infection in normal tissue while replication within tumor cells is unaffected.

When deciding on oncolytic treatment for patients, there are a few things to consider: the tumor must be large enough for an injection, away from large blood vessels, and the area must be accessible. It's also important to keep track of injected sites as well as non-injected tumors with photos, transparencies, etc.

Various clinical trials are currently underway and showing positive results within the cancer setting:

CALM Trial: Evaluating the efficacy of intratumoral injection CAVATAK (Coxsackievirus A21) in patients with late-stage malignant melanoma. Progression-free survival at 6 months was approximately 40%.

HF10 Trial: Attenuated mutant of HSV type-1 intratumoral injection for cutaneous/superficial solid tumors.

JX-594 (Pexa-Vec): Vaccinia poxvirus used in the smallpox vaccine. Encouraging results when given high-dose JX-594 intrahepatically for hepatocellular carcinoma.

OPTIM Trial (T-VEC/Talimogene Laherparepvec): Genetically modified HSV intratumoral injection for the treatment of unresected stage IIIB/C and IV melanoma, also showing response.

Many of the side effects associated with oncolytic treatment are similar in nature. Flu-like symptoms, along with local skin reactions are the most common, and may disappear after the initiation of the first treatment.

When it comes to clinical trial oversight for oncolytic immunotherapy treatment, compliance is more stringent when compared to other trials. Not only is the US Food and Drug Administration involved, but the Recombinant DNA Advisory Committee (RAC) and the Institutional Biosafety Committee (IBC) under the National Institute of Health (NIH) are involved as well.

While the safety of the patient is our number one priority, so is the safety of healthcare providers administering this kind of treatment. If your institution is participating in oncolytic immunotherapy clinical trials, biosafety guidelines must be followed: PPE, handling and storage, agent information, disposal of waste, and accidental exposure are all areas that require training and compliance for the nurse and/or the physician administering treatment. 

Are you familiar with oncolytic immunotherapy?