Efficacy and Safety of Liposomal Lactoferrin in COVID-19 Patients With Mild-to-Moderate Disease and in COVID-19 Asymptomatic Patients

COVID-19 is considered an ongoing international global health problem which already caused 12 million confirmed cases. No specific effective treatment has been identified so far, and available supportive therapies are intended just to severe patients. Asymptomatic and mildly symptomatic patients remain a transmission reservoir, with possible evolution to the most severe disease form, without a clear treatment indication.

Lactoferrin (Lf) is a multifunctional glycoprotein, belonging to transferrin family, secreted by exocrine glands and neutrophils and present in all human secretion. The pleiotropic activity of Lf is mainly based on its four different functions: chelate two ferric iron per molecule, interact with anionic molecules, enter inside nucleus and modulate iron homeostasis. The ability to chelate two ferric ions per molecule is associated to the inhibition of reactive oxygen species formation as well as this sequestration of iron, pivotal for bacterial and viral replication, is at the basis of its antibacterial and antiviral activity.

Moreover, Lf exerts its antiviral activity against the majority of the tested viruses by binding to heparan sulphate, while against few viruses by interacting with surface components of viral particles. The capability of Lf to exert antiviral activity, by binding to host cells or viral particles or both, strengthens the idea that this glycoprotein is "an important brick in the mucosal wall, effective against viral attacks". Lang and colleagues investigated the role of Lf in the entry of SARS pseudovirus into Myc cells. Their results reveal that Lf was able to block the binding of the spike protein to host cells, indicating that Lf exerted its inhibitory function at the viral attachment stage. The current accepted model suggests that Lf could block viral entry by interacting with heparan sulfate proteoglycans (HSPGs), which mediate the transport of extracellular virus particles from the low affinity anchoring sites to the high affinity specific entry as ACE-2.

We performed a prospective, interventional, pilot study to assess the efficacy of liposomal lactoferrin in COVID-19 patients with mild-to moderate disease and in COVID-19 asymptomatic patients.

Secondary objectives evaluated the safety and tolerability of liposomal lactoferrin for oral and intra-nasal use.

Patients were divided in two groups: COVID-19 mild-to-moderate patients (group 1a) and COVID-19 asymptomatic patients (group 2a), both of 15 patients. Other two groups (control groups) were included in the study to be paired to the above two case-groups. The "matched-pair-analysis" concerned the structural and clinical characteristics of the corresponding groups.

Group 1a received liposomal lactoferrin in 200 mg cps (equal to 100 mg of lactoferrin), 10 capsules per day for patients weighing less than or equal to 70 kg divided into 5 capsules in the morning and 5 capsules in the evening for 30 days for a total of 1 g of lactoferrin / day; patients with body weight over 70 kg, 15 capsules per day divided into 3 administrations / day for 30 days for a total of 1.5 g of lactoferrin per day; intra-nasal spray: 2 sprays per nostril 3 times a day, inhaling deeply during administration.

Group 2a received liposomal lactoferrin in 200 mg tablets (equal to 100 mg of lactoferrin), 5 capsules per day, 3 of which in the morning and 2 in the evening for 30 days (total dosage 500 mg of apo-lactoferrin per day); intra-nasal spray: 2 sprays per nostril 3 times a day, inhaling deeply during administration. Before administration, it was recommended to carefully clean the nasal cavity.

15 mild-to-moderate symptomatic patients in hospitalization regimen were enrolled in the control group 1b to be paired by age group and gender to the aforementioned experimental group (1a).15 asymptomatic patients were enrolled as a control group (group 2b) to be paired by age group and gender to the aforementioned experimental group (2a) Blood samples were collected at T0, T1 (after 15 days), T2 (after 30days). Body temperature and evaluation of related signs and symptoms were collected at T0. T1 and T2.

Complete blood count and chemistry panel, iron, transferrin, free iron plasma level, PCR, CK, IL-6, IL-10, TNF⍺, miR-1, miR-133, adrenomedullin, fibrinogen, d-dimer, were evaluated at T0, T1 and T2.

Eligible patients were over 20 years old, with a confirmed positivity to COVID-19 at the naso-oro-pharyngeal swab.

Exclusion criteria included pregnant and lactating women, patients taking nitric oxide and nitrates, patients with reported allergy to milk proteins, patients with a previous history of bronchial hyperactivity and patients with pre-existing respiratory diseases.