Cemiplimab has received full approval for patients with metastatic basal cell carcinoma. The most common adverse events include fatigue, musculoskeletal pain, rash, diarrhea, and anemia.
The FDA has granted a regular approval to cemiplimab-rwlc (Libtayo) to treat patients with metastatic basal cell carcinoma who previously received a hedgehog inhibitor (HHI) or for whom a HHI is not appropriate. 1,2
The agent received accelerated approval for this indication in February 2021 based on findings from an open-label, multicenter, non-randomized phase 2 trial (Study 1620; NCT03132636).3 The regulatory agency had also granted full approval to cemiplimab in those with locally advanced disease.
Cemiplimab is an intravenous infusion that is given over a 30-minute span after dilution. For patients with basal cell carcinoma, the infusion is given at a dose of 350 mg every 3 weeks until disease, progression, unacceptable toxicity, or for a maximum of 24 months. The most common adverse events (AEs) associated with single-agent cemiplimab include fatigue, musculoskeletal pain, rash, diarrhea, and anemia.4
Study 1620 enrolled a total of 138 patients with locally advanced or metastatic, nodal or distant, basal cell carcinoma who had progressed on a HHI, had not responded after 9 months of treatment with an HHI, or who proved to be intolerant to previous HHI treatment.4
If patients had autoimmune disease that needed systemic treatment with immunosuppressant agents within 5 years; a history of solid organ transplant; previously received anti–PD-1/PD-L1 therapy or other immune checkpoint inhibitors; infection with human immunodeficiency virus, hepatitis B or hepatitis C; or had an ECOG performance status of 2 or higher, they were excluded.
Study participants were given cemiplimab at 350 mg every 3 weeks for up to 93 weeks. Treatment was continued until progressive disease, intolerable toxicity, or completion.
Objective response rate (ORR) and duration of response (DOR) served as the trial's primary end points.
For those who did not have externally visible lesions, investigators evaluated ORR by RECIST v1.1 criteria. For those with externally visible lesions, they determined ORR by RECIST v1.1 criteria and World Health Organization criteria.
Of the 138 total patients who were evaluated in the efficacy analysis of the trial, 61% had locally advanced disease and 39% had metastatic disease.
In those with locally advanced disease (n = 84), the median age was 70 years (range, 42-89), and most patients were male (67%), White (68%), and had an ECOG performance status of 0 (61%). Additionally, 83% of patients had undergone at least 1 cancer-related surgical procedure and 50% previously received radiotherapy.
In those with metastatic disease (n = 54), the median age was 63.5 years (range, 38-90), and 70% were male. Eighty-seven percent of patients were White and 67% had an ECOG performance status of 0. In this group, 35% had distant metastases only, 9% had nodal disease only, and 54% had distant and nodal disease. Most patients (85%) previously underwent at least 1 cancer-related surgery and 59% received prior radiotherapy.
Data showed that cemiplimab elicited an ORR of 24% (95% CI, 13%-38%) in those with metastatic basal cell carcinoma and 32% (95% CI, 22%-43%) in those with locally advanced basal cell carcinoma. The complete response rates in these groups were 2% and 7%, respectively, and the partial response rates were 22% and 25%, respectively.
Among the 13 responders in the metastatic group, the median DOR was 16.7 months (range, 4.8-25.8+), with 92% of patients experiencing a DOR that lasted for at least 6 months. Among the 27 responders in the locally advanced group, the median DOR was not yet reached (range, 2.1-36.8+) with 85% of patients having responded for at least 6 months.
The safety of cemiplimab was evaluated in all 138 patients who had a median exposure of 45 weeks (range, 2.1-98) to the drug. Thirty-four percent of patients experienced serious toxicities with the agent, the most common of which included diarrhea (3.6%), urinary tract infection (3.6%), pneumonia (2.9%), and hemorrhage (2.2%).
Moreover, 4.3% of patients experienced adverse reactions that proved to be fatal; these patients experienced acute kidney injury (0.7%) and cachexia worsening because of colitis (0.7%).
Adverse effects (AEs) resulted in dose interruptions for 40% of patients. Fourteen percent of patients experienced AEs that resulted in the permanent discontinuation of the agent; these included diarrhea, acute kidney injury, hepatitis, and general deterioration in physical health.
The most common AEs observed with cemiplimab, that were experienced by 15% or more of trial participants, included fatigue (50%), musculoskeletal pain (36%), diarrhea (33%), rash (30%), upper respiratory tract infection (22%), pruritus (19%), hemorrhage (18%), and hypertension (17%).
The most frequently experienced grade 3 or 4 toxicities were hypertension, diarrhea, fatigue, musculoskeletal pain, hypokalemia, hyponatremia, pneumonia, urinary tract infection, visual impairment and decreased weight.