Retrospective study of tolerance to short initiation schedules in subcutaneous immunotherapy

With the aim of evaluating tolerance to new shorter initiation schedules in subcutaneous immunotherapy everyday clinical practice, a study was carried out using Pangramin Plus with initiation periods between 3 (Cluster) and 6 (Plus) weeks. All the information was processed retrospectively and both systemic (SR) and local (LR) adverse reactions occurring between September 2002 and February 2003 were recorded. A total of 353 patients (261 Plus and 91 Cluster) were included and 2,886 doses were administered (2,166 in initiation and 720 in maintenance). Of these, 800 were with Grass mix extract, 1,141 Grass mix + Olea, 273 Olea, 73 Dermatophagoides mix and 599 Dermatophagoides pteronyssinus. As regards adverse reactions (AR), 2.8% of patients showed SR and 4.8% LR, 1.2% of doses caused some type of reaction (SR and LR in 0.3% and 0.9%, respectively). The initiation schedule, first dose or allergens resulted in no significant differences in the frequency of adverse reactions. The Grass mix extract showed the highest frequency of AR. Sixty-seven percent of SR and 68% of LR were delayed. 64% of these reactions resolved spontaneously while the rest responded favourably to treatment. Adrenaline was administered on one occasion for immediate asthma. There were no cases of anaphylactic shock, hospitalisation or life-threatening situations. Pangramin Plus tolerance, therefore, can be classified as good, similar to conventional schedules, but with the benefits of shorter initiation schedules.

Immunotherapy safety: a prospective multi-centric monitoring study of biologically standardized therapeutic vaccines for allergic diseases

BACKGROUND

The fear of side-effects has led to strict regulations preventing a more widespread use of specific immunotherapy (SIT) in some countries, in spite of the low risk of systemic reactions (SRs) reported in well-controlled studies. The goal of the study was to carry out a prospective and multi-centric trial to evaluate the safety, risk factors and compliance degree of commercially available SIT.

MATERIALS AND METHODS

The study was carried out in 14 allergy departments from Spain. Four-hundred and eighty-eight patients with rhinitis and/or asthma were submitted to treatment with biologically standardized allergen extracts commercially available. They were administered following the European Academy of Allergy and Clinical Immunology guidelines.

RESULTS

Four hundred and twenty-three patients (86.7%) completed the treatment and remained under control at the end of the trial. Out of 17,526 administered doses, 17,368 doses (99.1%) were not associated with a reaction. Eighteen patients (3.7%) experienced 53 (0.3% of the doses) SRs. All immediate SRs were mild or moderate and responded well to ordinary treatment measures. There were no fatal reactions, anaphylactic shock or life-threatening reactions. A higher ratio of SRs was found among asthmatic and dust mite allergic patients, although multi-variable logistic analysis did not demonstrate any risk factor associated with SRs. There was also a subgroup of patients at risk for recurrent reactions, and therefore 40% of SRs had been avoided if the maximal number of SRs had been previously limited to only three SRs.

CONCLUSIONS

This multi-centric study showed that SIT was a safe treatment with a very good compliance. Future guidelines of SIT should limit the maximal number of SRs.

Olerance of a cluster schedule with a house dust mite extract quantified in mass units: multicentre study

The standardisation of allergenic extracts in micrograms of the major allergen has encouraged the search for new treatment schedules, with the purpose of shortening the number of visits and doses required to reach the maintenance dose without eliciting a greater risk of adverse reactions for the patients. With this objective, a prospective multicentre pharmacovigilance study was designed that included 200 patient with allergic rhinoconjunctivitis and/or allergic asthma sensitised to mites (Dermatophagoides pteronyssinu and/or farinae). The dose increment period was carried out using a cluster schedule, where the optimal dose wa reached after 4 visits, administering two doses in each visit. The duration of the study was 5 months and a total o 1902 doses were administered. At the end of the trial, 31 adverse reactions in 23 patients were recorded. Six of these were systemic (0.3% of t administered doses) recorded in 6 patients (3% of the sample). One was an immediate reaction (grade 1) and delayed (4 mild and 1 moderate). Two were asthmatic exacerbations, 2 cutaneous reactions, 1 rhinitis and 1 an unspecific symptom (not IgE-mediated). Two appeared upon administration of the first vial and the remaining 4 after administration of the third cluster. Therefore, the schedule tested presents an adequate tolerance profile, suggesting savings (compared to th conventional schedule of 13 doses per patient) of 1800 visits and 1000 treatment doses in the whole study.

The optimal immunotherapy cluster schedule in clinical practice

The efficacy of injective immunotherapy is no longer a matter of debate, but concerns about its safety and compliance problems (because of the number of visits required for the build-up phase) are limiting factors for wider usage. Different schedules have, therefore, been used in clinical trials with the aim of improving both safety and compliance. We investigated the effects on tolerance of modifications to the starting allergenic dose, of the pharmaceutical presentation of the allergen (aqueous or depot), of the change of the number and volume of the daily administrations through progressive adjustments of the so-called clustered schedule. We took the rate of local and/or systemic side effects as the primary criterion, and were able to gradually reduce the rate of systemic reactions per dose and per patient from 4.1% and 65% to 0.3% and 2.6%, respectively, through four progressive modifications of the starting schedule. According to our data, it is possible to reach the maintenance dose in only four visits with 2 administrations per visit. This was achieved either by switching from aqueous to depot extracts or by using depot extracts from the beginning. These results have been obtained without any kind of premedication and with a wide range of allergens, including mites, epithelia, pollens, and honeybee venom. We have shown that the number of injections administered following the conventional schedule could be reduced by 75%, shortening the build-up phase by 38.5%, without increasing the rate of side effects. We think clustered schedules could lead to a better compliance and to a broader use of injective immunotherapy.

Tolerance of a cluster schedule on the treatment of seasonal allergic respiratory disease with pollen extracts quantified in mass units

In order to evaluate the tolerance of a cluster schedule on specific immunotherapy (SIT), 306 patients were included in a multicenter study. The patients were suffering from rhinoconjunctivitis with/without asthma, caused by sensitization to olive and/or grass pollen. SIT was administered subcutaneously according to a cluster schedule in which the maintenance dose is reached after four visits (3 weeks). The extracts were biologically standardized with major allergens quantified in mass units. Local reactions appeared in 7.2% of the patients and 1.3% of the doses. Systemic reactions (SR) were recorded in 1.2% of the doses administered to 9.5% of the patients. No anaphylactic shock was registered, and all the SR responded fully and rapidly to treatment. There was no difference in SR according to diagnosis or allergen extract used. The majority of SR occurred with the administration of vial of higher concentration (Vial 2: 7 SR (22%), Vial 3: 32 SR (78%), p < 0.05). Of the 32 SR recorded with Vial 3, 13 (41%) were immediate, with no existing association between dose administered and appearance of SR. However, of the 18 delayed SR (56%), 14 occurred after the administration of the first two doses of Vial 3 and four occurred after administration of the second two doses (78% vs 22%, p < 0.05). On the other hand, this regime realized an important saving in cost and time compared to the conventional schedule (1581 fewer doses and 2754 fewer visits were necessary to reach the optimal dose). Considering all these factors, the clinical profile of the proposed regime may be qualified as good. However, future studies are necessary in order to better adjust the schedule to avoid the delayed SR that occurred after the administration of the first two doses of Vial 3.

Mercurialis annua: characterization of main allergens and cross-reactivity with other species

A multicentric study was conducted to evaluate the frequency of Mercurialis annua pollen sensitization in several areas of Spain and to select a population sample to characterize the main allergenic components in M. annua pollen. Patients were recruited from six hospitals in Spain. Out of 420 patients sensitized to pollens, 195 (46.4%) showed positive skin tests to M. annua, thus evidencing the high level of sensitization to the pollen of this plant in Spain. Thirty-seven sera with RAST class values to M. annua > or = 3 were selected for SDS-PAGE immunoblotting analysis. Two main allergenic components with molecular weights of 15.8 and 14.1 kD were detected in 59 and 51% of the sera, respectively, and they were identified as profilins. Isolation of the relevant allergens was made by affinity chromatography on a poly-L-proline-Sepharose column, followed by gel filtration and anion exchange chromatography in the micropreparative SMARTs System. A significant but low antigenic cross-reactivity between M. annua and Olea europaea, Fraxinus elatior, Ricinus communis, Salsola kali, Parietaria judaica and Artemisia vulgaris was demonstrated by several in vitro techniques.