Personalized cancer vaccines can help to stave off melanoma, suggested two phase I clinical trials published in Nature. The findings buoyed an emerging field that is using neoantigens — antigens that are unique to each patient's cancer — to prime the immune system to kill cancer cells.

In BioNTech's study, 13 patients with a history of recurrent melanoma received the firm's mRNA-based vaccine. Eight of these patients had no radiologically detectable lesions at vaccination and remained recurrence-free 23 months later. Of the other five patients, who had metastatic disease at vaccination, two experienced vaccine-related objective responses.

Separately, a team that includes co-founders of Neon Therapeutics treated six patients with a peptide-based vaccine. Four of these patients had no disease recurrence at 25 months. In the two patients who had recurrence after vaccination, subsequent treatment with Merck & Co's anti-PD1 antibody pembrolizumab led to complete and ongoing radiographic responses.

Other neoantigen-based cancer vaccine developers include Advaxis, Aduro Biotech and Gritstone Oncology (Nat. Rev. Drug Discov. 15, 663–665; 2016).