Low dose radiotherapy in the management of covid19 pneumonia (LOWRAD-Cov19). Preliminary report

Sanmamed, N.; Alcantara, P.; Cerezo, E.; Gaztañaga, M.; Cabello, N.; Gómez, S.; Bustos, A.; Doval, A.; Corona, J.; Rodriguez, G.; Duffort, M.; Ortuño, F.; de Castro, J.; Fuentes, M.; Sanz, A.; López, A.; Vazquez, M.

INTRODUCTION Low-Dose Radiation (LD-RT) has demonstrated to have anti-inflamatory effect and, preliminary results suggest it is feasible to treat COVID-19 pneumonia. MATERIAL AND METHODS We conducted a prospective single arm phase I-II clinical trial enrolling patients ≥ 50 years-old COVID-19 positive, at phase II or III with lung involvement at imaging study and oxygen requirement. Patients received 100 cGy to total lungs in a single fraction. Primary outcome was radiological response using severity and extension score on baseline CT, at day 3 and 7 after LD-RT. Secondary outcomes were toxicity using CTCAE v5, duration of hospitalization, blood work evolution and oxygen requirements using SatO2/ FiO2 index (SAFI), at day 3 and 7 after LD-RT . RESULTS Nine patients were included. Median age was 66 (IQR 57-77). Severity score was stable or decreased in the third CT but no statistically significant (p=0.28), however, there were statistically significant changes in the extension score (p=0.03). SAFI index significantly improved 72 hours and 1 week after LD-RT (p=0.01). Inflammatory blood parameters decreased one week after RT compared with baseline, only LDH decreased significantly (p=0.04). Two patients presented grade 2 lymphopenia after RT and another worsened to grade 4 being its baseline grade 3. Overall, the median number of days of hospitalization was 59 days (range 26-151). After RT the median number of days in hospital was 13 days (4-77). With a median follow-up after RT of 112 days (105-150), seven patients were discharged and two patients died, one due to sepsis and the other with severe baseline COPD from COVID-19 pneumonia. CONCLUSIONS Our preliminary results show that LD-RT was a feasible and well-tolerated treatment, with potential clinical improvement. Randomized trials are needed to establish whether LD-RT improves severe pneumonia.