Ragweed MATAMPL has been developed to provide pre-seasonal specific immunotherapy for patients with hypersensitivity to ragweed pollen (hay fever). This novel formulation is designed to provide a vaccine that will be efficacious with only four escalating dose injections administered before the start of the pollen season. In this Follow-up Study the Efficacy will be assessed by exposing allergic subjects to Ragweed pollen in an environmental exposure chamber EEC. Patient symptomatic response to pollen and patient quality of life in the EEC will be determined. Patients who previously completed two EEC portions of study Ragweed MATAMPL 204 and who had been treated with either Ragweed MATA MPL or Placebo before the 2005 ragweed season will be enrolled.

Inclusion Criteria:

• Patients must have completed both EEC periods of study P2DP5001; have had received either placebo or the top dose if they had been treated with Ragweed MATA MPL; and have had no major changes in medical history or health status since completing the study.

• Patients must be willing and able to give written informed consent and provide this consent prior to initiation of any study procedures, including initiation of washout of any concomitant medications.

• Patients must be willing and able to attend all study visits.

• Patients must observe the drug washout times listed in Table 3.2.3 prior to Screening (Visit 1). The use of other concomitant medications will be permitted if they are not expected to interfere with the ability of the patient to participate in the study and provided that they have been on a stable regimen (i.e. the same dose and schedule of administration) for eight weeks prior to screening).

• Women of childbearing potential must be using one of the following acceptable birth control methods:

  1. Intrauterine device (IUD) in place for at least three months;
  2. Barrier method (condom or diaphragm) with spermicide;
  3. Stable hormonal contraceptive for at least three months prior to study and through study completion;
  4. Abstinence;
  5. Not-heterosexual lifestyle.

• Patients must be able to follow instructions

Exclusion Criteria:

• Symptomatic for allergic rhinitis or allergic conjunctivitis from allergy to grass or trees at Visit 1.
• Symptomatic for significant perennial rhinitis at Visit 1, as judged by the Investigator.
• Concurrent disease that might complicate or interfere with investigation or evaluation of the study medication such as:
• Chronic use of antihistamines and other concomitant medications (e.g. tricyclic antidepressants) that would affect assessment of the effectiveness of study drug.
• Any systemic disorder that could interfere with the evaluation of the study medication.
• Upper or lower respiratory tract infection requiring antibiotics with 14 days of Visit 2.
• Diagnosis of sinusitis within 30 days of Visit 2.
• Any ocular disorder (other than allergic conjunctivitis) including presumed infectious ocular disease (bacterial, fungal, viral, etc.), which could interfere with the evaluation of the study drug.
• Hypersensitivity to the study drug excipients.
• Patients with active or quiescent tuberculous infection of the respiratory tract, untreated local or systemic fungal infection or bacterial or systemic viral infections or parasitic or ocular herpes simplex.
• Patients who have experienced nasal ulcers, nasal surgery or nasal trauma within 90 days of enrollment into this study.
• Clinical history of anaphylaxis or idiopathic anaphylaxis.
• Patients with contraindications for allergy vaccines.
• Patients with a clinical history of immunodeficiency, including those who are on immunosuppressant therapy.
• Patients in whom tyrosine metabolism is disturbed, especially in the case of tyrosinemia and alkaptonuria.
• Patients with contraindication to adrenaline.
• Subjects who are taking β-blockers for any indication including eye drops.
• Current diagnosis of chickenpox or measles.
• Clinical history of drug or alcohol abuse, at the Investigator's discretion, that would interfere with the patient's participation in the study.
• Clinical history of severe or uncontrolled cardiovascular, hepatic, renal and/or other diseases/illness that could be expected to interfere with the study.
• Clinical history, or evidence, of nasolacrimal drainage system malfunction.
• Study site staff or immediate relatives of study site staff or other individuals who would have access to the clinical study protocol.
• Patient who have participated in any other investigational study within 30 days of Visit 1 or concomitant with this study.