Abstract

e23139 Background: Oncologic patients are at risk of developing severe SARS-CoV-2 infection. Nirmatrelvir/ ritonavir (N/R) is an oral antiviral combination effective in minimizing risk of hospital/ ICU admission/ death, if administered early. Adverse events are rare, but significant drug-drug interactions may necessitate modification of other therapies. We aimed to evaluate implementation, safety, and outcomes in Greek patients with solid tumors and SARS-CoV-2 infection, treated with N/R. Methods: The study was designed by the Hellenic Society of Medical Oncology; 11 Greek oncology centers participated. We retrospectively, prior to February 2023, or prospectively thereafter, recorded the use or not of N/R in oncologic patients, patient characteristics and infection course/ outcomes, post patient consent. No ethical issues exist, since this is the official early therapy recommended by the Greek Ministry of Health. Results: Data from182 patients were collected (55.5% women), aged 24-89 years (median 63). Most (64.8%) had stage IV or metastatic disease. 87.4% were on treatment (66% chemotherapy, 32% immunotherapy, 7.5% hormone therapy). Co-morbidities were present in 45%. This was the primary infection for 89.6%. Most (61.1%) were vaccinated ≥ 3 doses, with 85.2% receiving ≥ 1 dose. N/R was administered to 92.3%; for the non-recipients, patient refusal was the major cause. Symptomatic/ positivity relapse were rarely noted. Adverse reactions were reported by 5.9%, all mild/ moderate, mainly dysgeusia. Temporary adjustment or postponement of oncologic treatment course was needed in 33.9%. Hospitalization was needed in 1.1%, and ICU admission in 0.55%. No deaths were recorded in a 30-day period post diagnosis, but 2 deaths with possible SARS-CoV-2 contribution on them were reported in the 1-3 month follow-up period. The small number of patients not administered N/R precludes extraction of statistically significant comparisons. Conclusions: There is limited experience on efficacy/ safety of early N/R therapy for SARS-CoV-2 infection in oncologic patients; our series is the largest at present. The study demonstrates wide oncologic patient use of N/R with minimal side effects. Although 1/3 of the patients had to adjust their oncologic therapeutic course, this may have been due to the infection per se rather than drug-drug interactions. Most patients exhibited full recovery, with 1.1% in need of hospitalization and no deaths recorded during the first post-infection month. N/R is a convenient, effective early treatment for SARS-CoV-2 infection in solid cancer patients.