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Background: The physiochemical modification of allergens to reduce allergenicity, while retaining immunogenicity, provides a chance for the administration of higher doses of immunotherapy, with a decreased risk of systemic reactions. Objective: To evaluate the safety of doses of depigmented glutaraldehyde-polymerized vaccine of Dermatophagoides pteronyssinus increasing those used in normal clinical conditions in comparison with regular doses of a non-modified vaccine. Materials and Methods: The study was double-blind, parallel and included two patient groups. Twenty-three patients were treated weekly during 9 visits for the build-up phase, followed by 2-weekly maintenance doses (a total of 11 injections per patient). Eleven patients (mean age 22 years) received immunotherapy with the standardized modified vaccine. The maximum dose used was the result of depigmenting and polymerizing 100 times the maximum dose used with the native extract. The maximum concentration used was 990 µg/ml of freeze-dried material. Twelve patients (mean age 24 years) received a standardized, unmodified allergenic extract. The maximum concentration used was 70 µg of freeze-dried material/ml, with a potency of 10 HEP_L/ml. The tolerance was evaluated recording all the side reactions related to immunotherapy and graded following the recommendations of the European Academy of Allergology and Clinical Immunology. Results: In both groups, all immediate local reactions were clinically not relevant. Patients treated with the native extract experienced 42 local immediate and 24 delayed reactions (1 of them had a diameter >10 cm), whereas patients treated with the modified extract experienced 30 local immediate and 21 delayed reactions (2 of them had a diameter >10 cm). Four systemic reactions in 2 patients, 1 immediate of grade 1 and 3 delayed of grade 2 were reported in the group treated with native extract and 1 delayed of grade 2 in the group treated with the modified preparation. Conclusions: The modified extract of D. pteronyssinus, used at concentrations which are 10 times higher than those regularly administered in clinical practice, demonstrated to be safe to treat D. pteronyssinus-sensitive patients. The major ity of the local reactions (immediate and delayed) were clinically not relevant (diameter <5 cm). No systemic reactions of grade 3 or 4 were noted.

Background Polymerized allergens conjugated to non‐oxidized mannan (PM‐allergoids) are novel vaccines targeting dendritic cells (DCs). Previous experimental data indicate that PM‐allergoids are readily taken up by DCs and induce Treg cells. This first‐in‐human study was aimed to evaluate safety and to find the optimal dose of house dust mite PM‐allergoid (PM‐HDM) administered subcutaneously (SC) or sublingually (SL). Methods In a randomized, double‐blind, double‐dummy, placebo‐controlled trial, 196 subjects received placebo or PM‐HDM at 500, 1000, 3000, or 5000 mannan‐conjugated therapeutic units (mTU)/mL in 9‐arm groups for 4 months. All subjects received 5 SC doses (0.5 ml each) every 30 days plus 0.2 ml SL daily. The primary efficacy outcome was the improvement of titrated nasal provocation tests (NPT) with D. pteronyssinus at baseline and at the end of the study. All adverse events and reactions were recorded and assessed. Secondary outcomes were the combination of symptom and medication scores (CSMS) and serological markers. Results No moderate or severe adverse reactions were reported. Subjects improving the NPT after treatment ranged from 45% to 62% in active SC, 44% to 61% in active SL and 16% in placebo groups. Statistical differences between placebo and active groups were all significant above 500 mTU, being the highest with 3000 mTU SL (p = 0.004) and 5000 mTU SC (p = 0.011). CSMS improvement over placebo reached 70% (p < 0.001) in active 3000 mTU SC and 40% (p = 0.015) in 5000 mTU SL groups. Conclusions PM‐HDM immunotherapy was safe and successful in achieving primary and secondary clinical outcomes in SC and SL at either 3000 or 5000 mTU/ml.

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