Pentoxifylline decreases serum LDH levels and increases lymphocyte count in COVID-19 patients: Results from an external pilot study

We have previously hypothesized that pentoxifylline could be beneficial for the treatment of COVID-19 given its potential to restore the immune response equilibrium, reduce the impact of the disease on the endothelium and alveolar epithelial cells, and improve the circulatory function. Serum lactate dehydrogenase (LDH) and lymphocyte count are accessible biomarkers that correlate with the severity of COVID-19, the need for hospitalization, and mortality, reflecting the host immune response's contribution to the seriousness of SARS-CoV-2 infection. We carried out this external pilot study on 38 patients with moderate and severe COVID-19 to test the effect pentoxifylline on parameters such as LDH, lymphocyte count, days of hospitalization, mortality, and proportion of patients requiring intubation. Twenty-six patients were randomized to receive 400 mg of pentoxifylline t.i.d. plus standard therapy (pentoxifylline group), while the rest received the standard treatment (control group). Linear regression models were built for statistically significant parameters. Pentoxifylline treatment was associated with a 64.25% increase (CI95% 11.83, 116.68) in lymphocyte count and a 29.61% decrease (CI95% 15.11, 44.10) in serum LDH. Although a trend towards reduced days of hospitalization, mortality, and proportion of patients requiring intubation was observed, no statistically significant difference was found for these parameters. Our findings open the possibility of pentoxifylline being repositioned as a drug for COVID-19 treatment with the advantages of a proven safety profile, availability, and no risk of immunosuppression; however, this evidence needs to be confirmed in a pragmatic randomized controlled trial.