Repurposing infectious diseases vaccines against cancer.

Abstract

e14564 Background: Vaccines used to prevent infection have long been known to stimulate immune responses to cancer as illustrated by the approval of the Bacillus Calmette–Guérin (BCG) vaccine to treat bladder cancer since the 1970s. The recent approval of immunotherapies has rejuvenated this research area with reports of anti-tumour responses with existing infectious diseases vaccines used as such, either alone or in combination with approved immune checkpoint inhibitors. This prompted us to review recent research activities using approved vaccines to treat cancer. Methods: PubMed and clinicaltrials.gov databases were queried for all 31 infectious diseases having at least one preventive vaccine approved, and all hits were reviewed for relevance. Only articles and trial registrations about infectious diseases vaccines used in an unmodified form as treatment for cancer, were included. The search was restricted in time, capturing articles from the year 2000 until November 2020. Results: A total of 1,754 PubMed abstracts and 549 trial registrations were screened. Data supporting a cancer therapeutic use was found for 16 of the 31 infectious diseases vaccines. For 10 (BCG, diphtheria, tetanus, human papillomavirus (HPV), influenza, measles, pneumococcus, smallpox, typhoid and varicella-zoster), clinical trials have been conducted or are ongoing. Within the remaining 6, preclinical evidence supports further evaluation of the rotavirus, yellow fever and pertussis vaccine in carefully designed clinical trials. The mechanistic evidence for the cholera vaccine, combined with the observational data in colorectal cancer, is also supportive of clinical translation. There is limited data for the hepatitis B vaccine and for the mumps vaccine alone. Four findings are worth highlighting: first, the superiority of intra-vesical typhoid vaccine instillations over BCG instillations in a preclinical bladder cancer model, which is now the subject of a phase I trial; second, the perioperative use of the influenza vaccine to limit and prevent the NK cell dysfunction induced by cancer surgery; third, objective responses following intra-tumoral injections of the measles vaccine in cutaneous T-cell lymphoma; fourth, objective responses induced by the HPV vaccine in skin squamous cell carcinoma. Conclusions: Sixteen infectious diseases vaccines have been or are currently being explored for repurposing in oncology. All vaccines are intended to induce or improve an anti-tumour (immune) response. Next to biological and immunological mechanisms, that are very different from one vaccine to another, also the mode of administration and combinations and sequence with other (immuno-)therapies deserve more attention in future research.