Efficacy and safety of birch pollen allergoid subcutaneous immunotherapy: A 2-year double-blind, placebo-controlled, randomized trial plus 1-year open-label extension.

BACKGROUND: Previous clinical trials with birch pollen subcutaneous immunotherapy have been conducted over a 1- to 2-year treatment period and involved mostly a single geographic location. OBJECTIVE: This study (EudraCT-Number: 2005-000025-35) intended to evaluate the effect of subcutaneous immunotherapy with high-dose hypoallergenic birch pollen allergoid in patients with confirmed moderate to severe seasonal allergic rhinitis/rhinoconjunctivitis over a 3-year course in 19 European centres. METHODS: Adults with confirmed birch pollen allergy (n = 253) were randomized to preseasonal placebo (n = 129) or active treatment (n = 124). Primary endpoint was change in Symptom Medication Score after 2 years treatment (2007). RESULTS: The change in Symptom Medication Score of active- vs placebo-treated patients for the Full Analysis Set (n = 227, 15.2% reduction, P = 0.0710) and Per-Protocol Set (n = 216, 16.7% reduction, P = 0.0523) showed a positive trend, although significance was not achieved. The primary endpoint, assessed in 2007, coincided with the lowest pollination during the study period. In a subgroup analysis of patients in the north-eastern region (n = 102), where birch is the major tree and consequently patients' exposure is higher, changes in Symptom Medication Score (32.7% reduction, P = 0.0034) and median number of well days (P = 0.0232) were highly significant in favour of the active group. During the open-label third year of treatment, the mean Symptom Medication Score of active-treated patients was further reduced despite an increased pollen count. Subcutaneous immunotherapy was well tolerated and consistent with the known safety profile. CONCLUSIONS AND CLINICAL RELEVANCE: Although the primary endpoint was not reached for the Full Analysis Set, a significant and clinically relevant effect on Symptom Medication Score was clearly demonstrated for the subgroup of patients in the north-eastern region of Europe, where birch is the predominant tree species. Proving efficacy of birch allergen subcutaneous immunotherapy is challenging due to the numerous factors influencing birch pollen allergen exposure in field studies.

SQ-standardized sublingual grass immunotherapy: confirmation of disease modification 2 years after 3 years of treatment in a randomized trial.

BACKGROUND: The main aim of specific immunotherapy is sustained effect due to changes in the immune system that can be demonstrated only in long-term trials. OBJECTIVE: To investigate sustained efficacy and disease modification in a 5-year double-blind, placebo-controlled trial, including 2 years of blinded follow-up after completion of a 3-year period of treatment, with the SQ-standardized grass allergy immunotherapy tablet, Grazax (Phleum pratense 75,000 SQ-T/2,800 BAU,(∗) ALK, Denmark) or placebo. METHODS: A randomized, double-blind, placebo-controlled, multinational, phase III trial included adults with a history of moderate-to-severe grass pollen-induced allergic rhinoconjunctivitis, with or without asthma, inadequately controlled by symptomatic medications. Two hundred thirty-eight participants completed the trial. End points included rhinoconjunctivitis symptom and medication scores, combined scores, asthma symptom and medication scores, quality of life, days with severe symptoms, immunologic end points, and safety parameters. RESULTS: The mean rhinoconjunctivitis daily symptom score was reduced by 25% to 36% (P ≤ .004) in the grass allergy immunotherapy tablet group compared with the placebo group over the 5 grass pollen seasons covered by the trial. The rhinoconjunctivitis DMS was reduced by 20% to 45% (P ≤ .022 for seasons 1-4; P = .114 for season 5), and the weighted rhinoconjunctivitis combined score was reduced by 27% to 41% (P ≤ .003) in favor of active treatment. The percentage of days with severe symptoms during the peak grass pollen exposure was in all seasons lower in the active group than in the placebo group, with relative differences of 49% to 63% (P ≤ .0001). Efficacy was supported by long-lasting significant effects on the allergen-specific antibody response. No safety issues were identified. CONCLUSION: The results confirm disease modification by SQ-standardized grass allergy immunotherapy tablet in addition to effective symptomatic treatment of allergic rhinoconjunctivitis.

Long-term clinical efficacy in grass pollen-induced rhinoconjunctivitis after treatment with SQ-standardized grass allergy immunotherapy tablet.

BACKGROUND: Sustained and disease-modifying effects of sublingual immunotherapy have never before been confirmed in a large-scale randomized, double-blind, placebo-controlled trial. OBJECTIVE: We sought to investigate sustained efficacy 1 year after a 3-year period of daily treatment with the SQ-standardized grass allergy immunotherapy tablet Grazax (Phleum pratense 75,000 SQ-T/2,800 BAU; ALK-Abelló, Hørsholm, Denmark). METHODS: A randomized, double-blind, placebo-controlled, phase III trial including adults with a history of moderate-to-severe grass pollen induced rhinoconjunctivitis inadequately controlled by symptomatic medications. The analysis set comprised 257 subjects at the follow-up. Efficacy end points were rhinoconjunctivitis symptom and medication scores, quality of life, and percentages of symptom and medication free days. Immunologic end points included grass pollen-specific serum IgG4 and IgE-blocking factor. Safety was assessed based on adverse events. RESULTS: Significant improvements in efficacy were consistently shown during 3 years' treatment. One year after treatment, the active group showed sustained reductions in mean rhinoconjunctivitis symptom scores (26%, P < .001) and medication scores (29%, P = .022) when compared with placebo. This level was similar to the efficacy observed during the 3-year treatment period. The differences in percentages of symptom- and medication-free days were significant during and 1 year after treatment. The active group also reported sustained and significant improvements in quality of life. Sustained clinical benefit was accompanied by immunologic changes. No safety issues were identified. CONCLUSION: Three years of treatment with the SQ-standardized grass allergy immunotherapy tablet resulted in consistent clinical improvement and accompanying immunologic changes that were sustained 1 year after treatment, which is indicative of disease modification and associated long-term benefits.

Specific immunotherapy to birch allergen does not enhance suppression of Th2 cells by CD4(+)CD25(+) regulatory T cells during pollen season.

INTRODUCTION: The aim of this study was to investigate the suppressive capacity of CD25(+) regulatory T cells on birch allergen-induced T-cell responses during the first birch pollen season after initiation of specific immunotherapy (SIT). METHODS: CD25(pos) and CD25(neg) T cells were purified from blood of birch-allergic SIT patients and birch-allergic controls, stimulated with birch pollen extract, and analyzed for T-cell proliferation and production of interferon gamma (IFN-gamma), interleukin (IL)-5 and IL-10. RESULTS: We show that allergen-induced proliferation and IFN-gamma production were suppressed equally well by CD25(pos) T cells from SIT patients and controls, while the IL-5 production was not suppressed by either of the groups. IL-10 levels were higher in SIT patients relative to controls only when CD25(neg) and CD25(pos) were cultured together. Furthermore, neither FOXP3 levels nor proportions of CD25(high) T cells were enhanced in SIT patients compared to allergic controls. DISCUSSION: These results suggest that the Th2-suppressive capacity of allergen-stimulated CD25(pos) Treg in vitro is not improved by SIT in spite of increased IL-10 production from T cells.

Efficacy of recombinant birch pollen vaccine for the treatment of birch-allergic rhinoconjunctivitis.

BACKGROUND: Recombinant DNA technology has the potential to produce allergen-specific immunotherapy vaccines with defined composition. OBJECTIVE: To evaluate the effectiveness of a new recombinant birch pollen allergen vaccine in patients with birch pollen allergy. METHODS: A multicenter, randomized, double-blind, placebo-controlled trial was undertaken to compare the following 3 vaccines in 134 adults with birch pollen allergy: recombinant birch pollen allergen vaccine (rBet v 1a), licensed birch pollen extract, natural purified birch pollen allergen (nBet v 1), and placebo. Patients received 12 weekly injections followed by monthly injections of the maintenance dose containing 15 microg Bet v 1 for 2 years. RESULTS: Significant reductions (about 50%) in rhinoconjunctivitis symptoms (rBet v 1, P = .0002; nBet v 1, P = .0006; birch extract, P = .0024), rescue medication (rBet v 1, P = .0011; nBet v 1, P = .0025; birch extract, P = .0063), and skin sensitivities (P < .0001) were observed in the 3 actively treated groups compared with placebo during 2 consecutive pollen seasons. Clinical improvement was accompanied by marked increases in Bet v 1-specific IgG levels, which were higher in the rBet v 1-treated group than in the birch and nBet v 1-treated groups. New IgE specificities were induced in 3 of 29 patients treated with birch pollen extract, but in none of the 32 rBet v 1-treated or 29 nBet v 1-treated patients. No severe systemic adverse events were observed in the rBet v 1-treated group. CONCLUSION: The rBet v 1-based vaccine was safe and effective in treating birch pollen allergy, and induced a highly specific immune response.

Once-daily sublingual allergen-specific immunotherapy improves quality of life in patients with grass pollen-induced allergic rhinoconjunctivitis: a double-blind, randomised study.

The effect of sublingual immunotherapy on quality of life (QoL) was examined in patients with grass pollen-induced rhinoconjunctivitis. Patients (n = 855) were randomised to once-daily grass allergen tablets (2,500; 25,000; or 75,000 SQ-T Phleum pratense extract; GRAZAX or placebo. Treatment was initiated 8 weeks before the start of the grass pollen season and continued throughout. If symptoms were present, patients received loratadine or placebo rescue medication. There were three major findings: in patients using loratadine, grass allergen tablets provided QOL benefits over placebo; Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score was 17% (p = 0.006) and 20% (p = 0.020) greater with 75,000 SQ-T tablet than with placebo at first and second seasonal visit, respectively; in patients not using loratadine, grass allergen tablets improved QoL more than placebo; RQLQ score was 21% greater (p = 0.021) with 75,000 SQ-T tablet at second seasonal visit; grass tablets (without loratadine) had a greater effect on QoL than loratadine alone. RQLQ score was 26% (p = 0.014) greater with 75,000 SQ-T tablets than loratadine at second seasonal visit. These data show that sublingual immunotherapy with grass allergen tablets improves QOL in allergic rhinoconjunctivitis, reduces symptoms, and that this effect is greater than rescue antihistamine alone.

Sublingual immunotherapy with once-daily grass allergen tablets: a randomized controlled trial in seasonal allergic rhinoconjunctivitis.

BACKGROUND: Specific immunotherapy is the only treatment modality that has the potential to alter the natural course of allergic diseases. Sublingual immunotherapy has been developed to facilitate access to this form of treatment and to minimize serious adverse events. OBJECTIVE: To investigate the efficacy and safety of sublingual grass allergen tablets in seasonal allergic rhinoconjunctivitis. METHODS: A multinational, multicenter, randomized, placebo-controlled trial conducted during 2002 and 2003. Fifty-five centers in 8 countries included 855 participants age 18 to 65 years who gave a history of grass pollen-induced allergic rhinoconjunctivitis and had a positive skin prick test and elevated serum allergen-specific IgE to Phleum pratense. Participants were randomized to 2500, 25,000, or 75,000 SQ-T grass allergen tablets (GRAZAX; ALK-Abelló, Hørsholm, Denmark) or placebo for sublingual administration once daily. Mean duration of treatment was 18 weeks. RESULTS: Average rhinoconjunctivitis scores during the season showed moderate reductions of symptoms (16%) and medication use (28%) for the grass allergen tablet 75,000 SQ-T (P = .0710; P = .0470) compared with placebo. Significantly better rhinoconjunctivitis quality of life scores (P = .006) and an increased number of well days (P = .041) were also observed. Efficacy was increased in the subgroup of patients who completed the recommended preseasonal treatment of at least 8 weeks before the grass pollen season (symptoms, 21%, P = .0020; and medication use, 29%, P = .0120). No safety concerns were observed. CONCLUSION: This study confirms dose-dependent efficacy of the grass allergen tablet. Although further studies are required, the greater tolerability of the tablet may permit immunotherapy to be available to a much broader group of patients with impaired quality of life caused by grass pollen allergy. CLINICAL IMPLICATIONS: For patients with grass pollen allergy, sublingual immunotherapy is well tolerated and can reduce symptoms and improve quality of life.

Effect of 2-year placebo-controlled immunotherapy on airway symptoms and medication in patients with birch pollen allergy.

BACKGROUND: Birch pollen is a common allergen in northern, central, and eastern Europe. Earlier studies of specific immunotherapy using birch pollen extract were not placebo-controlled or were only preseasonal. Long-term, placebo-controlled studies with subcutaneously administered standardized birch pollen extract are lacking. OBJECTIVE: The aim of this study was to evaluate the effect of immunotherapy with birch pollen extract on airway symptoms and use of medication in adult birch pollen-allergic patients in a double-blind, placebo-controlled trial. METHODS: Forty-nine patients with histories of birch pollen allergy from the upper and lower airways, positive skin prick test and conjunctival provocation test results, and in vitro specific IgE to birch pollen (Betula verrucosa ) extract were included. Immunotherapy with birch pollen extract was given during 2 consecutive years in a double-blind, randomized, placebo-controlled study. Clinical symptom scores from the upper and lower airways and use of rescue medication were registered throughout the pollen season. RESULTS: Forty-six patients reached the maintenance dose and were maintained on that dose during the 2-year study. The median symptom scores during the 1997 and 1998 seasons were 1.3 and 2.6, respectively, in the specific immunotherapy group and 2.1 and 4.3, respectively, in the placebo group. The differences between the groups were significant (P =.05 in 1997 and P =.005 in 1998). The placebo group used significantly more rescue medication during both seasons than the specific immunotherapy group (P =.004 for 1997 and P =.004 for 1998). CONCLUSION: Specific immunotherapy with birch pollen extract is an effective and safe treatment for reducing clinical allergy symptoms and medication use in birch pollen-allergic patients during the pollen season.