Journal of Clinical and Aesthetic Dermatology

Updates on Psoriasis & Cutaneou Oncology

An evidence-based, peer-reviewed journal for practicing clinicians in the field of dermatology

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S32 P r o c e e D i n G s JCAD jOUrnAl Of ClInICAl And AEsthEtIC dErMAtOlOgy september 2017 • volume 10 • number 9 • supplement resistance. PD1 comprises the PD1 t-cell coinhibitory receptors and ligands PD-l1 and PDl2, which are expressed in tumor and immune cells. McPyv-specific t-cells further express PD1. a treatment strategy of "block- the-blocker" has evolved using pembrolizumab (humanized monoclonal igG4 antibody that blocks PD1) or avelumab (blocks human monoclonal igG1 that blocks PD1). 1 72 Pembrolizumab was evaluated in a Phase 2 study of 25 patients with advanced Merkel cell carcinoma. investigators found the objective response rate during treatment was 56 percent (95% ci: 35–76), with 4 out of 25 patients achieving complete and 10 out of 25 partial response. 1 72 Most patients in this study responded by Week 12. adverse events were reported in 77 percent of patients, with 15 percent reporting more severe (Grades 3 or 4) events. in 2017, the fDa approved avelumab, the frst approved treatment specifcally for Merkel cell carcinoma. in a study of 88 patients with advanced Merkel cell carcinoma previously treated with chemotherapy, nine percent of the avelumab patients achieved complete response and 23 percent achieved partial response. 175 Duration of response was at least six months for the majority of patients (86%). thus, growing evidence suggests that checkpoint blockade should be considered the best treatment for achieving good response rates and durable results in patients with advanced Merkel cell carcinoma. treatment-related adverse events occurred in 71 percent of patients, but most were mild. avelumab represents an emerging standard of care for advanced Merkel cell carcinoma that shows promise. first-line therapy with pembrolizumab oders an objective response rate of 56 percent, far surpassing conventional chemotherapy, and these results were observed in both McPyv- positive and -negative tumors. 172 for that reason, PD-l1 expression should not guide clinical decision making in terms of whether to treat a patient with Merkel cell carcinoma with PD1 blockade. immune checkpoint blockers should be considered and may be enhanced by the potential synergistic edect between immunotherapy and radiotherapy. 176 Pdt + IMIQUIMOd + 5MfU: An UPdAtE Evolution of Pdt: the quest for short incubation and painless protocols. PDt is a well-established and familiar dermatologic treatment. it requires three fundamental things: oxygen (to create reactive oxygen species or ros), a photosensitizer (Pplx), and some sort of activating light source. among the fDa- approved photosensitizers used are 5-ala and methyl ester ala, the latter of which is not marketed in the united states. the activating light source may be red or blue light. the 20% ala with 14-to-18-hour incubation periods used in PDt today evolved from clinical trials and guorokinetic analyses. these treatments could be edective but they involved protracted incubation periods and were painful for patients. in a recent vehicle-controlled study, ala or vehicle for the treatment of aK was applied in broad-area application of face or scalp for one, two, or three hours or as spot application with two hours of incubation; following incubation, patients underwent blue- light activation. 177 at eight weeks, median aK clearance rates following a single treatment ranged from 36 to 57 percent. at 12 weeks, the median aK clearance rates of 68 to 79 percent (ala) were signifcantly better than the vehicle group (7%, p<0.0001). at Week 12, complete clearance was reported in 17 to 30 percent of ala patients versus two percent of vehicle patients (p=0.0041). With the goal of reducing treatment to a single PDt session, pretreatment can be used that may involve either 5-fu or imiquimod. Patients should apply the topical to the face (7 days) or scalp, trunk, or extremities (10 days). imiquimod 3.75% or 5% is applied over the course of seven days on the face and scalp. imiquimod should not be used for lesions on the trunk as there is a possibility of scarring. another way to enhance PDt eecacy is microneedling, which potentiates penetration of the ala or Mal. it is important to note that deeper microneedling is not approved by the fDa. increasing the temperature to 38.8° c during incubation of the extremities may also be helpful. 178 in a one-year study, 18 patients with at least 10 aKs on the upper and lower extremities (i.e., 20 pairs of extremities) were enrolled for ala-PDt at a single center. 179 following a one-hour incubation period, patients were exposed to 10 J/cm 417-nm blue light. the median baseline temperature of the treated lesions was 31.6° c, and the median maximum temperature during incubation was 41.2° c. lesions were counted and photographed at baseline and one week, then three, six, nine, and 12 months after treatment. at baseline, there was a total of 724 Grade 1 or 2 aKs (median 15 on each extremity). at three months, the median clearance was 90 percent, with results maintained over 12 months. at three and 12 months, the lesion count was 70 and 72, respectively. Grade 3 lesions did not resolve with treatment. Warming the extremities after ala application was well tolerated by patients and did not increase or exacerbate side edects. new consensus guidelines for PDt have recently been published by the american society of Dermatologic surgery (asDs) that recommend PDt as edective in the treatment of precancerous lesions, superfcial nonmelanoma skin cancers, ingammatory acne vulgaris, and certain other conditions. 180 an important and potential treatment-limiting consideration in

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