The response to a single dose of neoadjuvant PD-1 (programmed cell death protein 1) blockade predicts clinical outcomes in patients with stage III or IV resectable melanoma, researchers report.

“The most important and interesting point was that a single dose can result in complete eradication of the tumour, and the immune effect can occur extremely rapidly (within 7 days),” said first author, Dr Alexander Huang from Perelman School of Medicine, University of Pennsylvania, USA.

“Despite the clinical success of checkpoint blockade, we still understand relatively little about the precise mechanism(s) of response or resistance to these treatments,” Dr Huang and co-authors wrote in Nature Medicine.

Dr Huang and colleagues investigated pathologic and immunologic responses in melanoma tumors removed from 27 patients 17 to 42 days after a single neoadjuvant dose of the anti-PD-1 pembrolizumab and compared these responses with clinical outcomes.