New data presented at the virtual American Association for Cancer Research Annual Meeting (AACR) demonstrated promising antitumour activity induced by pembrolizumab in advanced cutaneous squamous cell carcinoma (CSCC). 

 

The data from a second interim analysis of the phase II KEYNOTE-629 trial of pembrolizumab found that patients with locally advanced CSCC demonstrated an objective response rate (ORR) of 50.0%. 

 

In the recurrent/metastatic group, the ORR was 35.2%, with the ORR in the total population found to be 40.3%. 

 

The disease control rate – defined as stable disease for 12 weeks or more plus ORR – was 64.8% in the locally advanced cohort and 52.4% in the recurrent/metastatic cohort. 

 

Specifically, 16.7% of patients in the locally advanced cohort experienced a complete response (CR) while 10.5% demonstrated CR in the recurrent/metastatic group. 

 

In the locally advanced and recurrent/metastatic cohorts,  33.3% and 24.8% had a partial response, respectively – 24.1% and 28.6% with stable disease and 17.1% with stable disease for 12 weeks or more. 

 

In addition, the 12-month progression-free survival (PFS) rates were 54% and 36.4% for the locally advanced and recurrent/metastatic cohorts. 

 

Meanwhile, overall survival (OS) rates in the locally advanced and recurrent/metastatic cohorts were found to be 73.6% and 61.0% respectively, with a median OS of 23.8 months in the recurrent/metastatic group. 

 

“From the subgroup analysis, overall response was generally consistent across most subgroups analysed in both cohorts,” said Brett Hughes of the Royal Brisbane and Women’s Hospital during a presentation of the results. 

 

“In the recurrent/metastatic cohort, there was a slightly higher response rate observed in patients who received pembrolizumab in the first line. This was more in the range of 50% versus 33% for those that have had prior treatment. Although responses were observed, regardless of PDL1 expression, an increase in objective response was observed in those who had a CPS of 1 or greater, or a TPS score of more than 50%,” he added.