Current Standards of Care & Advances in Immunotherapy
A Roundtable Discussion:
Other Immunotherapy Delivery Methods
Listen to the Podcast
Panelists
Intranasal
Dr. Nelson: I’m probably the only person at the table who’s done a study on intranasal immunotherapy. It is extremely effective but the problem is preventing symptoms while you’re administering it. You try to do that is by spraying cromolyn into the nose before the extract, but it doesn’t work that well. Many years ago when Roy Patterson was working with his polymerized ragweed extract they did a study using the polymerized ragweed intranasally. And they had no symptoms before the season and excellent results during the season. So I think if we could get a really good allergoid this might return as a viable option, but not with the current extracts.
Epicutaneous
Dr. Nelson: There are two European studies25,26 that are similar. They used patches that contained about the equivalent of the grass tablet or half of the tablet, so it was pretty strong. It was put on once a week and left on for 24 hours in one group and 48 hours in the other group. One group did repeated tape stripping of the skin to increase the absorptive capacity of the patch and the other put 3 percent salicylic acid in the patch mixture, which apparently also increases the penetration. With 12 weekly patches, both showed a reasonably good response the first year and continuing response the second year without any further treatment. So this certainly warrants continued exploration.
Dr. Finegold: There’s an article26 on the subject by Senti out of the Zurich Group that also suggests epicutaneous is a promising approach. I don’t know if they defined the immunologic mechanism, but dendritic cells of the skin seemed to be the important factor.
Dr. Nelson: That’s the presumption, but I think the immunological response isn’t different; it’s just another way of getting it into the immune system.
Intralymphatic
Dr. Cox: Intralymphatic might be the future.
Dr. Nelson: Dr. Finegold and I were at a meeting27 where the people who investigated that approach spoke and it engendered great interest. I think we should appreciate that these researchers are infectious disease experts and the concept came from vaccination for infectious diseases. They had a lot of animal data that showed how much greater an immune response you get with just a very small amount injected into a lymph node as opposed to large amounts injected under the skin. They now have one study.28 They’re still actively pursuing it and the results are remarkable. Three injections at monthly intervals produce the equivalence of 36 months of subcutaneous immunotherapy at the end of three years. The dose was the same as used for the subcutaneous route. The lymph node can be palpated but you also can use ultrasound to locate it for the injection. They said you can inject a whole cc of extract into one inguinal lymph node without pain, which allows high dosing of multiple allergens with no extra cost.
Dr. Finegold: Actually, their study shows that you need just a fraction of what you would need to do it subcutaneously. Their point was that when we do it sub-Q we’re actually slowly going to the regional lymph node where all the action takes place. And this system sort of cuts out the middle man, so it looks very promising. The other interesting thing about their preliminary data is that if you’re dealing with a very good antigen, intralymphatic doesn’t have greater efficacy than sub-Q. If you’re dealing with not such good allergens as our extracts are compared to, say, a flu injection, it really is a great enhancement to therapy. You get much better results. So I think this is very, very promising.
Dr. Wallace: So would we be co-managing with our radiology colleagues?
Dr. Finegold: No, you don’t have to do ultrasound. We all can feel lymph nodes; the inguinal node is the one you pick up first.
Dr. Nelson: The problem is the level of obesity in the United States. For most people you can palpate it, but when you can’t, you can use ultrasound.
References
Other topics:
• Sublingual immunotherapy (SLIT)
• Subcutaneous immunotherapy (SCIT)
• The current and future role of the allergist in immunotherapy
Perspectives Article published in the November 2011 issue of Annals of Allergy, Asthma and Immunology.