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Hi. I'm Natalie Jackson from MD Anderson, in Houston, Texas and I'm going to be speaking on viral oncolytic therapies. The first part is what is a viral oncolytic? There's two ways it can be used, either as the therapy itself, or as a vector for the delivery of other therapies, such as genetic therapies. I'll be speaking on it as a therapy. It is FDA approved in melanoma as TVEC, that is a genetically modified herpes simplex virus and it works by targeting the tumor cells causing lysis and activating the immune system that way.
The patients that this is used for, is currently stage III or IV melanoma patients. Through the research and literature, it has proven to be most effective in patients that were treatment naïve and patients that had a lower tumor burden, specifically stage III-B, stage III-C or stage IV-M1a patients. You usually target the largest lesion, and as we go through treatment, sometimes you'll target the newer lesions as opposed to necessarily just the largest.
The way it works is the TVEC is injected into the tumor and it does not invade healthy cells. That's how it was genetically modified. We removed two of the genes so that it would only attack tumor cells. It then replicates within the tumor cell, causing lysis, releasing GM-CSF, as well, which activates the dendritic cells and attracts T-cells. These T-cells then become memory cells that remember how to identify the cancer cells to continue the therapy, even when TVEC is not being administered.
To do this, of course, since it is a live virus, you need PPE. So the nurse practitioner or physician who's administering the drug and anybody involved in the area needs to have goggles, gown, gloves, and face mask. You also need virucidal wipes to cleanse the room after the patient has been treated. You also need an occlusive dressing to cover the wound and tumor that you've treated. Of course, the TVEC syringe and needle will go in a sharps container at that time, as well.
For the dressing site, so you'll have to switch gloves after you've injected the tumor, and then you wash it with alcohol and then cover it with a Tegaderm and 4 x 4, wipe the Tegaderm clean with alcohol, and then you apply a new Tegaderm on top of the other, once the alcohol has dried. Patients need to keep this on for a week as they are sloughing live virus for that long. So patients who have family members that are pregnant or immune compromised should not come in contact with the tumor or the body fluids for one week after the injection. If the dressing falls off at home, they do need to reapply a new occlusive dressing and throw the other one in a Ziploc baggie into the trash.
Side effects from this therapy are mild usually. Most patients will experience side effects, typically flu-like symptoms, fever, chills, mild nausea, injection site discomfort, joint pain. This does resolve after day five. Typically it's just the first 24 to 48 hours, though.
The other thing that we're concerned about, of course, is cellulitis at the tumor injection site. So that is something that needs to be closely monitored for and addressed early. The key thing, though, is that if patients do have a history of herpes or shingles and they have an outbreak, the use of acyclovir or other antivirals, you have to remember it could limit the benefit the patient's receiving from the TVEC. So you have to balance the treatment of the shingles or herpes outbreak with the possible cancer benefits.
Nursing consideration - of course, avoid exposure when you can. And if you become exposed, if it's a needle stick, follow your institutional guidelines. If it is a fluid exposure to the eyes, flush the area for 15 minutes with clean water. If you spill it, use your appropriate cleanup guide at the institution. And then again, just very clear, pregnant women or immunocompromised people should not administer the VEC or be involved in the dressing changes.
Patients, of course, need to consider this. TVEC is given every two weeks, so this is a time commitment, financial commitment, scheduling commitment. Of course, if it's curing their cancer, it's worth it. That's just something to discuss with the patient before starting therapy. Patients do need to be educated about their isolation status for seven days, avoid pregnant and immunocompromised people, and safe sex.
So, my name is Natalie Jackson. Thank you for listening to my presentation. Enjoy your day.