ABSTRACT
Background: The susceptibility of advanced cancer patients treated with immune checkpoint inhibitors (ICI) for viral infections has not been investigated. Currently, there are no robust data supporting the efficacy, safety and recommendation for influenza vaccination in cancer patients receiving ICI. Methods: The prospective, multicenter, observational INVIDIa-2 study investigated the clinical efficacy of influenza vaccination in advanced cancer patients with solid tumors receiving ICI between October 2019 and January 2020. The incidence of influenza-like illness (ILI, primary endpoint) was observed until April 30, 2020. Secondary endpoints included a non-prespecified analysis for COVID-19. Results: The study enrolled 1279 patients;1188 were evaluable. Of them, 11 patients developed ILI symptoms with confirmed diagnosis of COVID-19 (incidence of 0.9% and lethality of 72%, irrespective of the flu vaccination). Of the remaining 1177 patients, 574 received flu vaccination (48.8%). The ILI incidence was 7.7% (91 patients of 1177). Patients receiving the flu vaccine were significantly more frequently elderly (p<0.0001), former or active smokers (p<0.0001), affected by lung cancer (p=0.017) and by non-cancer comorbidities (p<0.0001) when compared to unvaccinated patients. The flu vaccine did not prevent ILI in the study population, irrespective of the vaccine type (quadrivalent vs trivalent, adjuvated vs non): the incidence of ILI was 8.2% in vaccinated vs 7.3% in unvaccinated patients (p=0.57). ILI complications were significantly less frequent for patients receiving flu vaccine (12.8% vs 40.9%, p=0.002). Hospital admission due to ILI occurred for 10 patients (11% of ILI cases;7 were unvaccinated). The ILI lethality was 2.2% (2 of 91 patients, both unvaccinated). Among vaccinated patients, those receiving adjuvated vaccines had lower incidence of ILI (4.8% vs 9.9%, p=0.046). Conclusions: Flu vaccination was not effective for ILI prevention, nor for COVID-19. Nevertheless, it reduced ILI complications, with no ILI-related deaths in vaccinated patients. We recommend the vaccine in ICI-treated cancer patients. Clinical trial identification: Eudract number of the trial: 2020-002603-18. Legal entity responsible for the study: FICOG Federation of Italian Cooperative Oncology Groups. Funding: FICOG (Federation of Italian Cooperative Oncology Groups, promoter and main sponsor), in turn funded by Seqirus UK and Roche S.p.A. for the present study. Disclosure: M. Bersanelli: Research grant/Funding (self), Research grant/Funding (institution), for the present study: Seqirus and Roche;Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution), Travel/Accommodation/Expenses, for other activities outside the present study: Pfizer, BMS, Novartis. S. Buti: Honoraria (self), Advisory/Consultancy, Speaker Bureau/Expert testimony, Research grant/Funding (institution): Bristol-Myers Squibb (BMS), Pfizer;MSD, Ipsen, Roche, Eli-Lilly, AstraZeneca and Novartis. U. De Giorgi: Research grant/Funding (institution): AstraZeneca, Roche, Sanofi;Honoraria (self): Astellas, Bayer, BMS, Ipsen, Janssen, Merck, Pfizer, Sanofi. P. Bonomo: Honoraria (self): Merck Serono, Angelini Pharma,. All other authors have declared no conflicts of interest.