Background and Importance At height of COVID-19 pandemic surge of delta variant, monoclonal antibodies became a vital treatment option for SARS-COV-2 positive outpatients at high risk of severe disease progression. Casirivimab and imdevimab (C/I) were used under EMA emergency use authorisation (EUA) and there was paucity of real-world data on safety and effectiveness.

Aim and Objectives The study aimed to describe drug safety, self-reported symptom burden and vaccination status in SARS-COV-2 positive outpatients within 90 days post-C/I infusion.

Material and Methods Prospective multicentric survey of SARS-CoV-2 positive outpatients with mild symptoms at high-risk of severe COVID-19 progression (defined criteria under EUA authorisation for C/I ambulatory administration) was conducted from September 2021 till January 2022 in three teaching hospitals. The data collected using electronic medical records comprised: patient details, vaccination status, date of SARS-COV-2 positive test, indication, adverse drug reaction to infusion, hospitalisation. Structured telephone questionnaire with symptom scoring adapted from BLAZE-1 trial was used on D (day) 0, D+7, D+29 and D+90 post- C/I infusion. Data were analysed using MS Excel. Ethics committee approval was obtained.

Results Within studied period 404 out of 471 patients were included (median age 66 years; 57.4% females). Excluded patients included prophylactic C/I, not consented or dropped out. 396 patients had the first COVID-19 episode. The most frequent indications included age over 65 years (55.5%), hypertension (56.8%), diabetes mellitus II (19.4%). C/I infusion was administered with a mean of 2.3 days (range 0–11 days) since virus positivity. 62.4% patients had complete vaccination (2 or 3 doses Comirnaty, 1 dose Janssen vaccine) prior C/I infusion. Adverse events were reported by 11.6% of patients, most commonly chills, fever, diarrhea. Subjective worsening of symptoms after C/I infusion was reported by 3.4% subjects by D+7. 11.6% patients observed no difference in symptom score between D0 and D+7. Altogether 85%; 92% and 93.6% patients reported improvement in symptom burden score by D+7, D+29 and D+90 respectively.

Conclusion and Relevance We describe real-life outpatient utilisation of C/I in terms of patient characteristics, self-reported symptom burden and adverse events. Therapeutic value of C/I timely administration is evident in high-risk patients with completed vaccination.

References and/or Acknowledgements 1. N Engl J Med. 2021 Jan 21;384(3):229-237

Conflict of Interest No conflict of interest