Risk for Deep Fungal Infections During IL-17 and IL-23 Inhibitor Therapy for Psoriasis
Psoriasis is an inflammatory disease with both skin and joint manifestations. Focused biologics have been developed to target specific cytokines implicated in psoriasis and are becoming increasingly utilized. Recently, the advent of newer biologics, including IL-17, IL-12/IL-23, and IL-23 inhibitors, have garnered interest as promising treatments for psoriasis and other inflammatory conditions. Although IL-17 and IL-23 have been studied in the pathophysiology of psoriasis, they also play a central role in immunologic defenses, including those against fungi. Therefore, use of these interleukin inhibitors may theoretically impair the immune system against deep fungal infections. We reviewed the available literature investigating the risk for invasive fungal infections in patients treated with IL-17 and IL-23 inhibitors for psoriasis or other inflammatory conditions. Randomized controlled trials (RCTs), including extended trials and clinical trials, were reviewed, and we found that although there was a small number of patients who developed superficial candidiasis, there were no reports of invasive fungal disease. Although these results support the safety and the low risk for deep fungal infection with these biologics, caution is still warranted, as these medications are relatively new. Appropriate screening and management of fungal disease should still be practiced when utilizing these medications in the treatment of psoriasis and other inflammatory conditions.
Practice Points
- The use of IL-17, IL-12/IL-23, and IL-23 inhibitors for psoriasis and other inflammatory conditions does not appear to increase the risk for deep fungal infections.
- Physicians should still be cautiously optimistic in prescribing these medications, as IL-17 and IL-23 play a central role in immunologic defenses, particularly against fungi.
- A high index of suspicion should be maintained for patients from endemic areas who are being treated with biologics.
IL-12/IL-23 Inhibitor
Risk for Deep Fungal Infection With Ustekinumab
The queried studies included 4 RCTs of 954 patients with psoriasis treated with ustekinumab (eTable).46-49 Within these trials, there were no reported cases of serious infections involving deep fungal organisms during the stated follow-up period. The literature search also found long-term safety data from the ACCEPT and PHOENIX trials that included 5437 patients with psoriasis treated with ustekinumab.66,67 There also were no demonstrated incidences of invasive fungal disease in these studies, with most cases of infection being common bacterial or viral infections.
IL-23 Inhibitors
Risk for Deep Fungal Infection With Risankizumab, Guselkumab, and Tildrakizumab
The queried studies included 16 RCTs or clinical trials for psoriatic patients treated with IL-23 inhibitors, including 5 with risankizumab,50-54 9 with guselkumab,55-63 and 2 with tildrakizumab.64,65 Within these trials there were no observed cases of serious infections with deep fungal disease.
COMMENT
Our literature review has demonstrated that there does not appear to be an increased incidence of deep fungal infections for patients treated with IL-17, IL-12/IL-23, or IL-23 inhibitors for psoriatic disease. All of the reviewed studies found no cases of invasive fungal infections for patients with psoriasis treated with secukinumab, ixekizumab, brodalumab, ustekinumab, risankizumab, guselkumab, or tildrakizumab. Patients with other inflammatory conditions, such as ankylosing spondylitis, rheumatoid arthritis, and asthma, also did not appear to show an increased incidence of deep fungal disease.
Although these results show promising safety data for the use of these biologic therapies in treating inflammatory conditions, caution still is warranted, as these medications still are relatively new, with FDA approvals within the last 5 years. Safety data among different study populations also cannot be derived without further investigation, and much of the available literature is limited in long-term data. More extended trials or registry data from a large, broadly representative cohort are necessary to establish the long-term safety and risk for deep fungal infections with IL-17 and especially the newer IL-23 inhibitors.
A small percentage of patients from the reviewed literature did develop superficial candidiasis. This outcome can be expected, as the central role of IL-17 and IL-23 has been recognized in immunologic protection against infections, specifically against fungi.11 Because all of the fungal infections reported for patients on IL-17 inhibitors were superficial candidiasis, guides for practical management and treatment should be implemented to standardize future research and care. A proposed screening algorithm for patients on these biologic therapies involves safety monitoring, including inspection of the oral cavity, folds, and genitals, along with inquiring about symptoms such as burning, dysgeusia, and dysuria.68 If infection is suspected, confirmation by culture, molecular method, or optimally with esophagoscopy can be performed, and appropriate treatment may be initiated.68 Patients with candida infections of the oral cavity, folds, or genitals can be placed on topical therapy such as nystatin, amphotericin B, ciclopirox, or other azoles, while those with infections of the esophagus can be started on oral fluconazole.68
Although there were no reported cases of deep fungal infections, the theoretical risk for developing one while on IL-17 and IL-23 inhibitors may warrant further screening prior to beginning therapy. The TNF inhibitors approved for the treatment of psoriasis currently contain a black box warning for risk for disseminated and extrapulmonary histoplasmosis, coccidioidomycosis, blastomycosis, and other invasive fungal infections, which may highlight the importance of thorough evaluation and awareness of endemic areas for patients on biologics. Prior to initiating treatment with TNF inhibitors, current suggestions involve performing a thorough examination along with keeping a high index of suspicion for invasive fungal infections in patients who live in or have traveled to endemic regions.69
Screening for invasive fungal infections for patients on TNF inhibitors involves questioning about potential exposures, such as demolition of old buildings, bird roosts, or spelunking.70 Serologies or antigen testing can be used routinely, but as these tests are insensitive, empiric antifungal therapy should be initiated if there is high enough clinical suspicion.71 Currently, there are no clinical guidelines regarding fungal screening and initiation of IL-17 and IL-23 inhibitors for treatment of psoriasis and other inflammatory conditions, but careful stewardship over using these effective medications should still be practiced.
Upon review of the available safety data on the use of IL-17 and IL-23 inhibitors for the treatment of psoriasis and other inflammatory conditions, there does not appear to be an increased incidence of deep fungal infections. Physicians, however, should still be cautiously optimistic in prescribing these medications, as there is a theoretical risk for infection for all patients on biologics. A high index of suspicion for patients presenting with symptoms of fungal infections should be maintained, and appropriate diagnosis and management should be initiated if they do occur.
