SAN DIEGO – A
“These skin reactions can cause pain, itching, and emotional and social distress that may severely impact activities of daily living,” Aleksandr Itkin, MD, a dermatologist at Scripps MD Anderson Cancer Center, San Diego, said at the annual Cutaneous Malignancy Update. An estimated 30%-50% of patients on immune checkpoint inhibitors (ICIs) experience cutaneous adverse events, he said, which leads to dose reduction or discontinuation of ICIs in 20% of cases.
Clinicians first observed these side effects in 2011, with the Food and Drug Administration approval of ipilimumab, a human cytotoxic T-lymphocyte antigen 4 (CTLA-4)–blocking antibody, for metastatic melanoma, followed by the programmed death receptor-1 (PD-1) inhibitors nivolumab and pembrolizumab, which were approved in 2014 for the same indication.
Courtesy Dr. Aleksandr Itkin
Dr. Aleksandr Itkin
Since then, more ICIs showing similar adverse cutaneous reactions have been approved by the FDA. These include avelumab, atezolizumab in combination with cobimetinib and vemurafenib, and a combination of relatlimab, an anti-LAG-3 antibody, with nivolumab.
Among the targeted therapies, the BRAF inhibitors vemurafenib and dabrafenib alone or in combination with MAPK pathway inhibitors cobimetinib and trametinib, which are a first-line therapy for V600 BRAF mutated metastatic melanoma, are associated with their own set of cutaneous reactions. The oncolytic modified herpes simplex virus T-VEC (talimogene laherparepvec), approved by the FDA in 2015 for the treatment of unresectable stage IIIB-IV metastatic melanoma, also results in cutaneous reactions that have been found useful in assessing the therapeutic outcome of this agent.
According to a 2020 CME article on the dermatologic adverse events that occur after treatment initiation with ICIs, the time of onset of psoriasiform rash is within the first 3 weeks, maculopapular rash and pruritus in the first 4-6 weeks, lichenoid eruption in the first 7-12 weeks, and bullous pemphigoid in weeks 13-15. The most severe reactions – SJS, toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) – usually occur after 2-3 months of treatment.
A subsequent retrospective cohort study of patients in the United States treated with ICIs for a variety of systemic malignancies and matched controls found that the ICI-treated group had a significantly higher incidence of pruritus, mucositis, erythroderma, maculopapular eruption, vitiligo, lichen planus, bullous pemphigoid, Grover disease, rash, other nonspecific eruptions, and drug eruption or other nonspecific drug reaction. Patients with melanoma and renal cell carcinoma and those receiving combination therapy were at a higher risk of cutaneous immune-related adverse events.
Another study, a prospective trial of 617 patients with various advanced cancers (including melanoma), found that both severe and mild skin toxicities were significantly associated with improved progression-free and overall survival.
According to Dr. Itkin, erythema multiforme, SJS, and TEN have been reported with anti-PD1, anti-CTLA4, and BRAF inhibitors. In TEN induced by vemurafenib, an in vitro analysis showed cross-activation of lymphocytes with dabrafenib and with sulfamethoxazole. “This means you that may want to avoid sulfonamides in patients with serious hypersensitivity to vemurafenib, and vice versa,” he said at the meeting hosted by Scripps MD Anderson Cancer Center.