Each of 3 patients treated with cemiplimab achieved a near complete response.
A recent retrospective observational study reported 3 cases of near complete response in patients with penile squamous cell carcinoma (SCC) who were treated with cemiplimab. According to study authors Rouvinov et al, this is the first known real-world report of near complete response with cemiplimab in this indication.
Study authors noted that current guidelines for recommended treatment include chemotherapy regimens, these can be accompanied by substantial side effects. There is, they wrote, a need for broader and less toxic therapies for this indication.
Because of high Programmed Cell Death Protein 1 (PD-L1) expression associated with penile cancers, investigators sought to explore responses when treated with cemiplimab, a monoclonal antibody that targets PD-L1, in patients with penile SCC.
Patients included in the study (n=3) had been diagnosed with penile SCC and had received treatment with immunotherapy between January 2020 and February 2023. Patients were required to be at least 18 years of age with an Eastern Cooperative Oncology Group (ECOG) Performance Status score between 0 and 4. Participants were excluded from the study if they had a history of treatment with systemic therapy for an advanced or metastatic condition, autoimmune disease, or if they were currently undergoing immunosuppressive treatment.
At baseline, relevant patient data was collected, including details of treatment, mortality date, disease progression date, overall response rate, treatment-related toxicities, and ECOG performance status score. All participants were required to undergo disease staging, baseline laboratory testing, and viral infection testing prior to treatment initiation.
The first patient, a 77-year old male, received 2 cycles of cemiplimab therapy. Following these cycles of treatment, investigators noted a decrease in lymph node size and an overall decrease in lesion count. The patient remains on treatment with cemiplimab as of July 2023, with complete radiological response noted as early as September 2022.
In the second patient, a 75-year old male, a FDG-PET-CT scan 4 months into treatment with cemiplimab revealed significant reductions in metabolic absorption in both the skin lesions and the right inguinal lymph node. As of July 2023, the patient remains on treatment with cemiplimab and has demonstrated complete radiological response.
The third patient, an 83-year old male, exhibited a significant reduction in tumor size and lesions upon visual examination following the first cycle of cemiplimab.
Study limitations, as noted by investigators, included the study's retrospective nature, limited quantity of data, and limited inclusion criteria allowing for only patients who had been ineligible for treatment with cisplatin to participate.
"The recommended therapy for patients with advanced penile carcinoma is chemotherapy with a cisplatin- and taxane-based regimen. It is important to note that some patients are ineligible for cisplatin and little is known about carboplatin-based combinations," study authors wrote. "In our article, efficacy was shown with cemiplimab as a first-line treatment in patients who were ineligible or refused combined cisplatin-based chemotherapy or surgery. Our patients achieved almost complete radiological response. Undoubtedly, radical surgery or radiotherapy will remain an important part of the treatment strategy for responding patients and remain the standard of care for localized pSCC, but the use of [immunotherapy] will certainly reinforce the need to develop predictive biomarkers."
Rouvinov K, Mazor G, Kozlener E, et al. Cemiplimab as first line therapy in advanced penile squamous cell carcinoma: A real-world experience. J Pers Med. 2023;13(11):1623. Published 2023 Nov 20. doi:10.3390/jpm13111623