Study: NCT00078195

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: omalizumab
Description: A minimum equivalent dose of 0.016 mg/kg/IgE (IU/mL) every 4 weeks will be administered. Omalizumab is administered in two separate phases. In the pre-treatment period omalizumab will be administered to condition the participants to an immune tolerance state. Omalizumab will be also administered after RIT and during the maintenance immunotherapy phase.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: omalizumab
Description: A minimum equivalent dose of 0.016 mg/kg/IgE (IU/mL) every 4 weeks will be administered. Omalizumab is administered in two separate phases. In the pre-treatment period omalizumab will be administered to condition the participants to an immune tolerance state. Omalizumab will be also administered after RIT and during the maintenance immunotherapy phase.

Intervention type: BIOLOGICAL
Group type: PLACEBO_COMPARATOR
Intervention: Placebo omalizumab
Description: The placebo for omalizumab will contain the excipients and diluents of the omalizumab.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: Placebo omalizumab
Description: The placebo for omalizumab will contain the excipients and diluents of the omalizumab.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: Ragweed rush immunotherapy (RIT)
Description: RIT will consist of a series of injections containing ragweed extract. The series of injections will have progressively greater amounts of ragweed extract: starting from the 1:1000 dilution of the maintenance vial and progressing to the 0.3 mL of 1:10 dilution of the maintenance vial or the maximally tolerated amount.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: Ragweed rush immunotherapy (RIT)
Description: RIT will consist of a series of injections containing ragweed extract. The series of injections will have progressively greater amounts of ragweed extract: starting from the 1:1000 dilution of the maintenance vial and progressing to the 0.3 mL of 1:10 dilution of the maintenance vial or the maximally tolerated amount.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: Placebo rush immunotherapy (RIT)
Description: The placebo for rush immunotherapy will contain the diluents and histamine.

Intervention type: BIOLOGICAL
Group type: PLACEBO_COMPARATOR
Intervention: Placebo rush immunotherapy (RIT)
Description: The placebo for rush immunotherapy will contain the diluents and histamine.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: Ragweed immunotherapy (IT)
Description: Participants will receive weekly maintenance IT dosing for a total of 12 weeks.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: Ragweed immunotherapy (IT)
Description: Participants will receive weekly maintenance IT dosing for a total of 12 weeks.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: Placebo immunotherapy (IT)
Description: The placebo for immunotherapy will contain the diluents and histamine.

Intervention type: BIOLOGICAL
Group type: PLACEBO_COMPARATOR
Intervention: Placebo immunotherapy (IT)
Description: The placebo for immunotherapy will contain the diluents and histamine.