OBJECTIVES: To suggest alterations to cost-effectiveness models of biologics for moderate to severe psoriasis that would account for the utility of partial responders. METHODS: Clinical guidelines dictate that, for the continuation of a biologic in treatment of moderate to severe psoriasis, a 75% improvement from baseline on the Psoriasis Area Severity Index (PASI) must be achieved which serves as a Minimum Clinical Endpoint (MCE). However, patients achieving a PASI 50% improvement may also continue treatment if supplemented by a minimally important difference (MID) in health-related quality of life (5-point improvement on the Dermatology Life Quality Index (DLQI)). Since cost-effectiveness models of biologic medications for treatment of psoriasis do not account for the utility of any patients achieving a PASI 50% improvement, a systematic review was conducted to identify whether patients achieving a PASI 50% improvement also achieved a 5-point DLQI improvement in large RCTs. Statistical inference from data obtained therein was used to modify equations used in cost-effectiveness calculations. RESULTS: The systematic review returned 8 studies that reported DLQI improvements in terms of Mean ± SD, stratified by increasing PASI response. Each study returned mean DLQI scores for patients with a PASI 50% improvement that were within one standard deviation of a 5-point DLQI improvement. This finding drove proposed alterations in which patients with a PASI 50% improvement are counted as “partial responders” or “non-responders” based on the probability of whether or not a 5-point DLQI improvement was attained. CONCLUSIONS: The literature confirms that patients with severe psoriasis can achieve a MID in DLQI improvement without achieving an MCE in PASI improvement. This study proposes alterations to the methodology of cost-effectiveness calculations that recognize the meaningful improvement in outcomes achieved by this subset of patients. Nevertheless, future studies should examine how these alterations affect overall cost-effectiveness of biologics for psoriasis.