12 THERAPY

Looking at immunotherapy in asthma

Data from a double-blind, randomised US study of immunotherapy with ragweed pollen for adults with allergic asthma revealed some positive effects on objective measures of disease, but only limited clinical effects overall. I

64 patients completed 1 year, and 53 completed 2 years, of treatment in this study. Patients received injections of placebo or extract of ragweed pollen at a dose that was titrated until the maximum tolerated dose or the maintenance dose of O.5ml (lOllg of antigen) was reached. Each group received maintenance doses every 2 weeks for 3 months and thereafter every 4 weeks. Skin-prick testing, pulmonary function testing, and bronchial challenges with ragweed and methacholine were performed after 2 years' therapy.

Both groups had some improvements in asthma symptoms, with only slightly greater improvements in the immunotherapy group, suggesting a benefit associated with regular physician consultations and adjustment of medication.

Mechanisms and benefits unclear 'The mechanisms of the beneficial effects of

allergen immunotherapy are far from clear' , says Dr Peter J Barnes from London, UK, in an editorial commentary that accompanies the study results.2 He adds that there can be few indications for the use of such immunotherapy in the routine treatment of adults or children with asthma, particularly in view of the low efficacy, the risk of adverse effects and the high cost associated with allergen immunotherapy.

While significant differences between immuno­therapy and placebo recipients were noted in terms of laboratory measurements and skin and pulmonary response to ragweed allergens, differences in the severity of asthma were less clear, say the study authors. I In view of the effective medications avail­able for allergic asthma, they consider that only few patients with continuing asthma would want to under­take immunotherapy for a single, seasonal allergen. However, immunisation for multiple allergens may be studied in the future, suggest the study authors. 1. Creticos PS, et aI. Ragweed immunotherapy in adult asthma. New England

Joumal of Medicine 334: SOI-506, 22 Feb 1996 2. Barnes PJ . Is immunotherapy

for asthma worthwhile? New England Journal of Medicine 334: 531-532, 22 Feb 1996 10031 • ..,

2 Mer 1996 INPHARMAe 0156-270319611026-000121$01.000 Adlalnlernetlonel Limited 1996. All rights reHrvecI