Cemiplimab for patients with either metastatic or locally advanced basal cell carcinoma showed antitumor activity in a phase 2 trial.
For patients with locally advanced basal cell carcinoma (BCC) after hedgehog inhibitor (HHI) therapy, cemiplimab (Libtayo) demonstrated clinically significant antitumor activity, according to results from an open-label, single-arm phase 2 trial (NCT03132636) that were published in Lancet Oncology.
The primary end point of objective response assessed by independent central review (ICR) was observed in 31% (95% CI, 21%-42%) of patients in the study population. Six percent of patients experienced a complete response and 25% experienced a partial response.
“To our knowledge, this cemiplimab study is the first to show clinical benefit of a systemic therapy and supports the recent indication of cemiplimab in the USA as the first immunotherapy, for patients with locally advanced basal cell carcinoma after HHI therapy or for whom HHIs are not appropriate,” wrote the investigators who were led by Alexander J. Stratigos, MD.
A total of 84 patients with locally advanced BCC were enrolled between November 16, 2017, and January 7, 2019, and treated with cemiplimab. At the February 17, 2020, data cutoff point, 19 patients remained on treatment, 13 completed the 93-week planned treatment, and 52 discontinued treatment.
Median time to response evaluated by ICR was 4.3 months and median duration of response was not reached by the data cutoff point. Estimates for duration of response using the Kaplan-Meier method were 91% (95% CI, 68%-98%) and 85% (95% CI, 61%-95%) at 6 months and 12 months, respectively. Eighty percent of patients experienced disease control (95% CI, 70%-88%) and 60% of patients experienced durable disease control (95% CI, 48%-70%).
Survival analyses were also estimated using the Kaplan-Meier method. Based off 38 events, median progression-free survival (PFS) was estimated at 19 months (95% CI, 9–not evaluable [NE]). Median overall survival (OS) at the data cutoff point was also not reached, with the estimated proportion of patients alive at 2 years observed at 80% (95% CI, 63%-90%).
Grade 3 and 4 treatment-emergent adverse effects (TEAEs) were observed in 48% of patients, with common TEAEs including hypertension (5%), colitis (5%), fatigue (4%), urinary tract infection (4%), and visual impairment (4%). Serious treatment-related AEs were seen in 35% of patients, with 11% of effects determined to be related to study treatment. No treatment-related deaths were observed.
Treatment discontinuations occurred in 11% of patients, with grade 3 a below effects observed. Grade 3 effects included adrenal insufficiency, asthenia, colitis, hypophysitis, and immunemediated hepatitis. Grade 2 effects included acute kidney injury, colitis, enterocolitis, and immunerelated hypothyroidism. Grade 1 effects included colitis and renal failure.
Eligible patients were aged 18 or older with ECOG performance scores of 0 or 1. Further eligibility required a histologically confirmed diagnosis of either metastatic BCC or locally advanced BCC with progression on or intolerance to prior HHI therapy.
Patients included in the population were treated with cemiplimab at 350 mg intravenously every 3 weeks for up to 93 weeks until disease progression or unacceptable toxicity. The primary end point for the research was objective response measured by IRC with some secondary end points including investigator-assessed objective response, duration of response, PFS, OS, and safety.
“These results fill a longstanding gap regarding the absence of treatment options for patients with locally advanced basal cell carcinoma after firstline HHI therapy. Objective responses with HHI therapy occur in approximately half of patients with locally advanced basal cell carcinoma, but most do not have complete responses,” concluded the investigators.
Stratigos AJ, Sekulic A, Peris K, et al. Cemiplimab in locally advanced basal cell carcinoma after hedgehog inhibitor therapy: an open-label, multi-centre, single-arm, phase 2 trial. Lancet Oncol. 2021;22(6):848-857. doi:10.1016/S1470-2045(21)00126-1