Enzyme potentiated desensitization
Enzyme potentiated desensitization, or EPD, is a treatment for allergies developed in the 1960s by Dr. Len McEwen in the United Kingdom. EPD uses much lower doses of antigens than conventional treatment, with the addition of an enzyme, beta glucuronidase. EPD is available in the United Kingdom and Canada for the treatment of hay fever, food allergy and intolerance and environmental allergies, and was available in the United States until 2001, when the Food and Drug Administration revoked approval for an investigative study which it had previously sanctioned which had allowed EPD to be imported into the USA without being licensed. The reason cited for revoking approval was that complex mixtures of allergens such as used in EPD treatments were not allowed under FDA rules.
EPD is under development for the treatment of autoimmune disease by a United Kingdom company called Epidyme[1] which has been granted a United Kingdom patent. There are encouraging results [2] in an experimental model of rheumatoid arthritis and work on treatments for further autoimmune diseases is planned. Suitable autoimmune diseases for possible future EPD research include multiple sclerosis, type 1 diabetes and myasthenia gravis.
EPD treatment
The enzyme beta glucuronidase appears to potentiate the desensitizing effect of a small dose of allergen. The quantities of both are smaller than those occurring naturally in the body, but not so small that they can be regarded as homeopathic. Intradermal injections are used. The treatment takes 3-4 weeks before any effect is seen. For food and environmental allergies and intolerances treatments are typically given at two monthly intervals at first, but the interval between treatments is gradually lengthened. Hay fever is treated with two shots of EPD outside the pollen season.
Mechanism for EPD
The treatment uses dilutions of allergen and enzyme to which T-regulatory lymphocytes are believed to respond by favouring desensitization, or down-regulation, rather than sensitization. Once activated these lymphocytes travel to lymph nodes and reproduce or stimulate similar T-lymphocytes.
Evidence for the Effectiveness of EPD
EPD is considered experimental and ineffective by most doctors and allergists[3] . However, there is some theoretical evidence for the efficacy of EPD in the treatment of hay fever as a result of a number of a number of very small placebo-controlled, double-blind trials with limited numbers of patients, but a major study with 183 patients in the world renowned British Medical Journal in 2003 found no effect. All but one of these trials showed a significant improvement in the symptoms with probabilities of 0.001 to 0.01 (a chance of one in a thousand to one in a hundred that the results of the trial would be seen by chance alone assuming EPD had no effect),[4] [5] [6] [7] [8] [9] [10] [11] while one trial showed no overall effect.[12]
Safety of EPD
While the efficacy of EPD is sometimes the subject of controversy among the medical community, the safety of EPD is accepted by others. In a study under the control of an Investigational Review Board and reported by the American EPD Society 5,400 patients received at least 3 doses of EPD with no severe reactions.[13] No 'serious' complications have been reported in more than 300,000 doses given since 1966.
By contrast, a working party of the British Society for Allergy and Clinical Immunology reviewed the role of conventional high dose specific allergen immunotherapy (not EPD) in the treatment of allergic disease and recommends high dose specific allergen immunotherapy for treating summer hay fever uncontrolled by conventional medication and for wasp and bee venom hypersensitivity. For the recommended indications the risk:benefit ratio was found to be acceptable for conventional immunotherapy (not EPD) provided patients are carefully selected; in particular, patients with asthma should be excluded and injections should be given only by allergists experiences in this form of treatment in a clinic where resuscitative facilities are available and patients remain symptom free for a observation period after injection which is sufficient to detect all serious adverse reactions.[14]
By contrast conventional (escalating dose) immunotherapy, although used to treat tens of millions of people in the United States according to the American Academy of Allergy, Asthma, and Immunology, has a death rate of less than one in one million, and has thus been thought responsible for at least 29 deaths in the United Kingdom, and is now banned in the United Kingdom except in hospital under close observation for patients with serious asthma.[15]
Restrictions on EPD
EPD has not been developed for treatment of contact dermatitis and allergy to drugs or insect stings.[16]. It is not FDA approved.
References
- ^ Epidyme website use of EPD to treat autoimmune diseases.
- ^ EPD treatment of rheumatoid arthritis proof of concept results on Epidyme website use of EPD to treat autoimmune diseases.
- ^ Mass. Medical Society (2003). "Enzyme-Potentiated Desensitization Doesn't Improve Allergic Rhinitis". Journal Watch. 912: 1.
- ^ Brostoff J., Fell P. (1990). "A single dose desensitisation for summer hay fever". Eur. J. Clin Pharmacol. 38: 77–79.
- ^ Astarita C., Scala G., Spoviero S., Franseze A. (1996). "Effect of enzyme potentiated desensitisation in the treatment of pollenosis : A double-blind placebo-controlled trial". J. Invest. Allergol. Clin. lmmunol. 6 (4): 248–255.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Longo G., PoIi F., Bertoli G. (1992). "Clinical efficacy of a new hyposensitising treatment, EPD (Enzyme Potentiated Desensitisation) in the therapy of pollenosis". Riforma Med. (107): 171–176.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Angelini G., Curatoli G., D’Argento V., Vena G. A. Pollinosi (1993). "Una nuova metodica di immunoterapia. Med. J. Surg. Med": 253-256.
{{cite journal}}: Cite journal requires|journal=(help)CS1 maint: multiple names: authors list (link) - ^ Di Stanislao C.. Di Berardino L., Bianchi I., Bologna G. (1997). "A double-blind, placebo-controlled study of preventive immunotherapy with EPD in the treatment of seasonal allergic disease". Allergie et lmmunologie. 30 (2): 39-42.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Caramia G., Franceschini F., Cimarelli Z.A., Ciucchi M.S., Gagliardini R., Rufllni E. (1996). "The efficacy of EPD, a new immunotherapy, in the treatment of allergic diseases in children". Allergie et lmmunologie. 28 (9): 308-310.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Di Stanislao C., Angelini F.; et al. (2002). "Beta glucuronidase short-term immunotherapy prevents seasonal rhinoconjunctivitis in grass pollen allergic patients by modifying dendritic cell phenotype". Allergy. 57 (Suppl 73): 76–77.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Boscolo M. A., Brivio G. "E.P.D. preventive therapy (McEwen method) vs. placebo: a double-blind trial". Poster presentation. European Congress of Allergy & Clinical Immunology. Brussels, July 1999.
- ^ Radcliffe M. J., Lewith G. T., Turner R. G., Prescott P., Church M. K., Holgate S. T. (2003). "Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study". British Medical Journal. (327 2 August.): 251–254.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Shrader, W A (2001). "The American EPD Study: 1993–2000" (PDF). White Paper for United States Senators and Representatives. Enzyme Potentiated Desensitization (EPD). p. 14. Retrieved 2006-09-16.
{{cite web}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help) - ^ AJ Frew (1993). "Injection immunotherapy. British Society for Allergy and Clinical Immunology Working Party". BMJ. (307): 919–23.
- ^ JA Douglass, FC Thien and RE O'Hehir (1997). "Immunotherapy in asthma". Thorax. (52): 22–29.
- ^ L.M. McEwen "Enzyme Potentiated Desensistization" (patient pink handbook) 1993