Vall d'Hebron Barcelona Hospital Campus is leading a clinical trial promoted by Karyopharm Therapeutics that will study the effects of selinexor, a drug indicated to treat cancer, in patients with severe COVID-19. Vall d'Hebron is one of only two participating centers in Spain and we have already included the first patient. The other center is the Hospital de Salamanca and in the next few days new hospitals from around the world will be added.Dr. Benito Almirante, head of the Infectious Diseases Service of the Vall d'Hebron Hospital and head of the research group on Infectious Diseases of the Vall d'Hebron Research Institute (VHIR) will be responsible for coordinating the clinical trial.This is a randomized, single-blind, phase II trial that will assess the activity and safety of low-dose oral selinexor (KPT-330) in patients with severe COVID-19 infection. 230 patients will be recruited.Patients who will undergo this treatment are in an urgent clinical situation after a diagnosis of COVID-19 confirmed by PCR and must be over 18 years of age.The study will measure the time to clinical improvement evaluating clinical aspects such as the absence of fever for 24 hours without the need for antipyretics (paracetamol), an oxygen saturation greater than or equal to 94% without oxygen support, or a respiratory rate less than or equal to at 24 breaths per minute, among other parameters.On the other hand, other aspects such as the mortality rate after 28 days, the percentage of patients who have required mechanical ventilation or admission to the ICU, the general evolution of patients according to age (older or younger than 70 years) will also be included.In the same way, the anti-inflammatory and immune effects of selinexor will be analyzed, as well as its tolerability and safety at low doses to determine the capacity of this drug to modify the course of the disease.