A Single-blinded, Randomized, Placebo Controlled Phase II Trial of Prophylactic Treatment With Oral Azithromycin Versus Placebo in Cancer Patients Undergoing Antineoplastic Treatment During the Corona Virus Disease 19 (COVID-19) Pandemic

Inclusion Criteria: * Histologically confirmed cancer diagnosis * Ongoing systemic antineoplastic treatment irrespective of application route * Age ≥ 18 years * Life expectancy of at least 3 months * Adequate renal, cardiac and liver function * Corrected QT time (QTc) ≤ 450 ms * Eastern Cooperative Oncology Group (ECOG) performance status of \< 3 * Capable of understanding the study and giving informed consent * Negative COVID-19 test at study entry as measured by routine testing Exclusion Criteria: * Use of any investigational agent within 28 days prior to study start * Patients with active opportunistic infections * Pregnant or lactating women * Women of childbearing potential and male subjects not willing to use adequate contraception methods during the study period * Hypersensitivity to azithromycin or other macrolides * Concurrent medication with ergotamine, theophylline, digitalis * Inability to swallow tablets