Successful bimekizumab retreatment after secondary failure in multi‐biologic‐resistant psoriasis

Dear Editors, A 22-year-old male with longstanding severe plaque psoriasis with baseline Psoriasis Area and Severity Index (PASI) score of 48 and no history of psoriatic arthritis presented with widespread active disease despite multiple prior systemic therapies. His disease course had been characterized by frequent treatment failures or secondary loss of response. Previous therapies included acitretin, ciclosporine, apremilast, narrowband UVB phototherapy, methotrexate, and multiple biologics: adalimumab 40 mg every 2 weeks for eight months; etanercept 50 mg weekly for 5 months; infliximab 500 mg 8-weekly for 4 months; ustekinumab 90 mg 12-weekly for 7 months; secukinumab 300 mg 4-weekly for 8 months; ixekizumab 80 mg 4-weekly for 6 months; risankizumab 150 mg 8-weekly for 2 months; and guselkumab 100 mg 4-weekly for 30 months and again for 4 months. The patient had previously achieved his best clinical response with 11 months of 4 weekly dose 320 mg bimekizumab; however, he developed a secondary loss of efficacy following generalized sunburn, with subsequent Koebnerization and suberythrodermic flare (Figure 1). He was transitioned to tildrakizumab 200 mg subcutaneously every four weeks in combination with oral methotrexate 20 mg weekly, but his psoriasis remained active with ongoing flares toward the end of each dosing interval. On examination, he had extensive erythematous, scaly plaques involving the upper and lower limbs and trunk, with relative facial sparing and associated scalp involvement. The PASI score was 19 at the 11-month review after commencing tildrakizumab. Given his prior favorable response to bimekizumab, limited alternatives and recent weight loss of 30 kg due to lifestyle modifications, a retrial of bimekizumab 320 mg every four weeks was commenced. Concomitant therapy included methotrexate 7.5 mg weekly. At six months following bimekizumab retreatment, the patient demonstrated substantial clinical improvement with minimal residual disease (PASI < 2; Figure 2). He reported improved quality of life and reduced symptom burden. This clinical response was maintained for 12 months despite a gradual weight gain of 7 kg over 6 months. No injection-site reactions or systemic adverse effects were observed. This case highlights the clinical response following retreatment with bimekizumab in a patient with treatment-resistant plaque psoriasis. Secondary loss of biologic efficacy is well recognized and may be mediated by immunogenicity (such as development of antidrug antibodies), pharmacodynamic tolerance, or external inflammatory triggers.1, 2 In this patient, it coincided with significant sunburn and Koebnerization, suggesting that acute inflammatory stress may have contributed to treatment failure rather than loss of drug response. Importantly, reintroduction of bimekizumab in combination with concomitant low-dose methotrexate resulted in rapid and sustained clinical improvement, with the patient achieving nearly clear skin within six months. Methotrexate was used in this patient as an adjuvant therapy to optimize disease control; however, the patient's substantial weight loss may also have influenced the improved response, as clinical studies have shown improved disease control with weight loss management.3, 4 Although these findings involve different agents and populations, they support weight reduction as a potential modifier of therapeutic response in psoriatic disease. Accordingly, the patient's weight change is an important potential confounder rather than proof that retreatment alone restored efficacy. This case also adds to evidence supporting sequential biologic switching and retreatment in severe psoriasis.5, 6 Despite extensive prior exposure to multiple biologic classes and small-molecule therapies, the patient achieved meaningful disease control without cumulative safety concerns. This highlights that retrial of a biologic can remain clinically effective, particularly when the previous response was robust and loss of efficacy appears temporally linked to modifiable external factors. Overall, this case underscores the importance of individualized therapeutic strategies in refractory psoriasis. Biologic retrial may represent a valuable option in selected patients, particularly when alternative treatments are limited and prior efficacy has been demonstrated. Further prospective studies are warranted to better define predictors of successful biologic response and to optimize treatment sequencing strategies in recalcitrant psoriasis. Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australasian University Librarians. None.