As stated in the CDR Clinical Review Report, the 150 mg dose of omalizumab failed to provide a clinically significant response in terms of UAS7 score at weeks 12 and 24. Therefore, CDR reanalysis did not consider scenario 2 and focused on the 300 mg dose of omalizumab from scenarios 1 and 3. Scenario 1 was identified to be the most representative of current Canadian clinical practice, where omalizumab will be used as a third- or fourth-line drug in the treatment of CIU, as mentioned in the Clinical Review Report. Scenario 3 is in line with requested listing criteria, where omalizumab would be used as a second-line drug.

1. Shortening of the time horizon to 10 years:

   1. In scenario 1, the ICUR increased to $65,495 per QALY.
   2. In scenario 3, the ICUR increased to $100,639 per QALY.
2. Treatment response (UAS7 ≥ 6) upon relapse (UAS7 ≤ 16) based on initial response probabilities:

   1. In scenario 1, the ICUR increased to $78,854 per QALY.
   2. In scenario 3, the ICUR increased to $95,434 per QALY.
3. Higher spontaneous remission rates (Toubi et al. [2004]⁸):

   1. In scenario 1, the ICUR increased to $67,083 per QALY.
   2. In scenario 3, the ICUR increased to $102,737 per QALY.
4. Re-treatment of patients in the mild urticaria health state:

   1. In scenario 1, the ICUR increased to $94,686 per QALY.
   2. In scenario 3, the ICUR increased to $127,576 per QALY.
5. Equating the costs of LTRAs to $0.00 (scenario 1 only):

   1. The ICUR increased to $52,986 per QALY.
6. Higher proportion of females to males for the all-cause mortality values:

   1. In scenario 1, the ICUR increased to $52,474 per QALY.
   2. In scenario 3, the ICUR increased to $81,130 per QALY.

For more detailed CDR reanalyses, see Table 13 in Appendix 5.

5.1. CADTH Common Drug Review Multi-Way Analysis

Upon conducting a multi-way analysis considering the limitations identified above, and assuming the manufacturer’s proposed 70% and30% patient split between severe and moderate patients respectively, in scenario 1, the ICUR for omalizumab 300 mg plus SOC versus SOC alone was $120,009 per QALY. Upon stratifying by severity (assuming 100% of patients are severe and 100% are moderate) considering these limitations, the ICUR ranges from $88,480 per QALY for the severe health state to $419,033 per QALY for the moderate health state.

In scenario 3, the ICUR for omalizumab 300 mg plus SOC versus SOC alone was $137,192 per QALY.

Upon stratifying by severity, the ICUR was $79,192 per QALY for the severe health state; for the moderate health state, omalizumab 300 mg plus SOC was dominated by SOC.

5.1.1. Price reduction analysis

A price reduction of approximately 50% to 60% would be needed such that the ICUR for omalizumab 300 mg plus SOC compared with SOC alone would be at commonly accepted thresholds (Table 2).

Table 2

CADTH Common Drug Review Reanalysis Price Reduction Scenarios.