A Case of Biologic Switching in Psoriasis and How to Optimize Outcomes with Ron Vender, MD

Ronald B Vender, MD

Switching biologic therapies in psoriasis is a common clinical challenge, often driven by loss of efficacy or patient preference, according to Ron Vender, MD, associate clinical professor of medicine at McMaster University in Hamilton, Ontario, Canada. "I got 99 problems, but the switch ain't one," he joked at the opening of his presentation A Case of Switching between Biologics, highlighting what he understands as the ease of transitioning between agents with an appropriate strategy. Vender presented a case in point at the 2025 Midwinter Clinical Hawaii Dermatology Conference being held in Hawaii, February 15-19.

65-Years-Old with 10-Year History of PsO

The patient was a 65-year-old man with a 10-year history of psoriasis who had failed topical therapies and narrowband UVB. Treatment had been initiated with ixekizumab with a standard loading dose. For the first 4 months, he did well, Vender said, but despite transitioning to every-4-week dosing, the JAK inhibitor’s efficacy waned and after 8 months when improvement was only modest. The patient, in consultation with the clinician, requested a switch in therapy.

"There are several strategies when faced with reduced efficacy," Vender explained. Options include increasing the dose, a tactic Vender said he never uses; reducing the dose interval, which he tried with this patient. Other options include adding a topical or another systemic agent or switching biologics. In this case, the patient opted for the switch.

What Leads to Switching?

The reasons for switching biologics typically fall into 1 of 4 categories, according to Vender. primary failure, ie, lack of initial efficacy; secondary failure, ie, initial efficacy that decreases over time; adverse events; and a shared decision made by the patient and clinician, ie patient preference.

"Primary failure, which really occurs with every biologic in a small percentage of patients, used to mean a response less than PASI 75," he said, referring to the Psoriasis Area and Severity Index, "but now it's more likely to be less than PASI 90, and in the future, it may be a response of less than PASI 100." The recommended period after which to assess treatment progress, he said, is 6 months. (ref)

Secondary failure can be the result of a range of patient-specific factors, Vender noted, including overweight or obesity, previous biologic failures, treatment adherence, and comorbidities, eg, diabetes, hypertension, or cardiometabolic disease. In Vender’s experience, side effects are less common reasons for switching biologic treatment for psoriasis. In some regions, insurance restrictions may also drive the decision.

No Washout Needed

Addressing the need for a washout period when switching biologics, Vender was clear: "We don't really need a washout period." The rationale is twofold—while some support the interval out of concern for overlap in immunosuppression, the reaction is minimal, Vender noted, as these therapies are immunomodulatory. The second reason supports patient quality of life, he added, citing data that show the risk for a psoriasis flare is greater than that for any adverse events associated with overlapping therapies. J Eur Acad Vernol

When failure of efficacy is the issue, Vender strongly recommended initiating the next biologic without delay. "We're going to start that next biologic at the shortest interval after stopping the previous biologic," which would be at the next scheduled dose of the biologic that has become ineffective. For example, when switching from ixekizumab to bimekizumab, the recommended interval is 4 weeks. speaker advises a switch at 4 weeks. If switching from ixekizumab to another agent, a shorter interval of 1 to 2 weeks could be appropriate.

Another Switch Followed by Success

Vender returned to the gentleman in his case study who had requested a switch from ixekizumab for waning response after an initial positive response. He was switched to bimekizumab 320 mg every 4 weeks for 4 months. When he had received 5 doses he returned to the clinic with a case of oral candidiasis, which was successfully treated with oral fluconazole 200 mg on day 1 followed by 100 mg daily for 7 days. He asked to be switched in an example of an adverse event triggering the need to change, the scenario Vender noted he hadn’t encountered often but definitely occurs. The patient also requested an oral medication. The final regimen comprised the selective tyrosine kinase 2 inhibitor deucravacitinib, 6 mg daily, combined with ixekizumab. "He did very, very well," the speaker reported, achieving PASI 100 and expressing satisfaction with the outcome.

The take-home message from the case, Vender emphasized, is that ultimately successful biologic switching requires individualized assessment and a flexible, patient-centered approach. You never know what pathway underlies the patient's disease or what agent they are most likely to respond to at first, Vender reminded. But, "My target is PASI 100 all the time," he concluded. "Because it's like an exam—I want to get 100, but if I get 90, that's not so bad."

Primary failure

Mrowietz U, Steinz K, Gerdes S. Psoriasis: to treat or to manage? Exp Dermatol 2014;23:705-9. Gulliver WG, et.al. JCMS. Vol 19, No 1 (January/ February) 2015;pp22-27

Secondary failure

Mrowietz et al J Eur Acad Dermatol Venereol 2014 Smith et al 2017 BJD

Washout not needed impact minimal

Risk for flares greater than the risk for AEs when switching

Mrowietz U, Kragballe K, Nast A, et al. J Eur Acad Dermatol Venereol 2011; 25 Suppl 3: 1–13.

2Downs Br J Dermatol 2010; 163: 433–434.