Recruitment difficulties

This study will evaluate the ability of the vaccine to produce antibodies against herpes zoster virus (shingles) and safety of vaccination with Varicella Zoster Vaccine in patients with moderate to severe psoriasis who will initiate biologic therapy 4 to 6 weeks after vaccination.

Varicella Zoster Vaccine will be administered 4 to 6 weeks prior to receipt of biological therapy and will be compared against placebo.

This double-blind study will enroll approximately 50 adult patients with moderate-to-severe plaque psoriasis in approximately 3 centers in Canada. Study products will be assigned randomly at a 4:1 ratio.

For each patient who is included, the study may last up to 22 weeks, including the screening and the follow-up period. During the study, subjects will come to the dermatology clinic up to 4 occasions: for a screening visit, Baseline visit, Day 42 as well as 84 days after they started taking the biological treatment for a last visit. If patients develop a varicella-like or shingles-like rash at any time after they received the vaccine, they will be requested to come back to the clinic within 72 hours of rash onset (preferably within 24 hours) for examination. Subjects will be asked to provide a lesion swab/vesicular fluid in this case.

Main Inclusion Criteria:

1. Outpatient men or women aged 50 years or older
2. Must have moderate-to-severe plaque psoriasis for at least 6 months, and for whom a decision to use biologic therapy has been made, with biologic therapy planned to be initiated within the next 4-6 weeks.
3. History of varicella, or having resided in Canada for at least 30 years.

Main Exclusion Criteria:

1. Have received Varicella Zoster Vaccine vaccine or known allergies to the Varicella Zoster Vaccine vaccine or its excipients including neomycin and gelatin
2. Primary and acquired immunodeficiency states due to conditions such as: acute and chronic leukemias, lymphoma, other conditions affecting the bone marrow or lymphatic system, immunosuppression due to HIV/AIDS, cellular immune deficiencies.
3. Current use of non-topical antiviral therapy with known activity against varicella-zoster virus.
4. Exposure to varicella or zoster within 28 days prior to vaccination.
5. Patients who are diagnosed with herpes zoster at the time of the vaccination.
6. Active untreated tuberculosis.