Official Title
Pilot Study on the Feasibility of Low Dose Radiotherapy for SARS-Cov-2 Pneumonitis (COVID-19 Low Dose Radiotherapy - COLOR 19)
Brief Summary

Low-dose radiotherapy treatment delivered to both lungs in patients with immune-related pneumonia following COVID-19 infection is backed up by biological and clinical bases that justify its use as a possible therapeutic option in these patients. This is a preliminary exploratory study (non-pharmacological interventional) to evaluate the feasibility and tolerability of low-dose radiotherapy treatment of SARS-Cov-2 immune-mediated pneumonia, for the subsequent implementation of a phase II study.This is a preliminary, monocentric, single-arm, interventional, non-pharmacological exploratory study. All enrolled patients will be treated with low-dose radiotherapy. Participants will undergo irradiation of the lungs, administered in a single fraction at the average prescription dose of 0.7 Gy (further details in the dedicated section).

Detailed Description


Since the first case of Severe Acute Respiratory Syndrome - Coronavirus - 2 (SARS-CoV-2)

infection and its subsequent clinical manifestation (COronaVIrus Disease 19, COVID-19) in the

city of Wuhan (Hubei, China) in December 2019, contagion abruptly spread to different regions

of China and, subsequently, to all continents. To date, 1 521 252 cases have been confirmed

worldwide. With the first case ascertained in Lombardy at the end of February 2020, Italy

soon became the first European country to face the exponential growth in the number of

infected people (to date -May 3, 2020-210,717 total cases, currently positive 100,179).The

disease turned into an actual health emergency due to the rapid spread and the need of

hospitalization and respiratory function support in Intensive Care Unit (ICU) for a

significant fraction of the patients. However, the clinical presentation of COVID-19 is

non-specific and extremely heterogeneous. Many patients are asymptomatic or exhibit mild

symptoms, which include cough, fever, general malaise with myalgias, anosmia and ageusia. The

most common changes in blood tests include lymphopenia, thrombocytopenia and increased

C-reactive protein and ferritin.

As emerged by clinical data, the viral infection could be divided into three different

phases: stage I, asymptomatic incubation period with little or undetectable viral load; stage

II, mild symptomatic period with considerable and detectable viral load; stage III, severe

symptomatic period with high viral load.

The definitive diagnosis requires a positive molecular test with Real Time PCR (RT-PCR)

method for SARS-CoV-2 on nasopharyngeal swab. However, this technique suffers from

sub-optimal sensitivity, which may require repetition on bronchoalveolar lavage. The

execution of chest CT is therefore essential, as it is characterized by high sensitivity and

can detect highly suggestive findings even in patients with negative RT-PCR.

Although the majority of infections resolve spontaneously without the need for specific

therapy, up to 20% of patients can develop severe clinical pictures with pneumonia

characterized by dyspnea, tachypnea and hypoxemia that requires treatment in a hospital

setting. Pulmonary involvement is typically bilateral, peripheral and basal in most cases,

presenting on CT scan with multifocal ground glass opacities and interstitial infiltrations;

complete resolution usually takes several weeks. Despite active treatment, about 5-10% of

cases can precipitate, often suddenly, into critical conditions including respiratory

failure, ARDS and multi-organ dysfunction that require ICU admission and are burdened with

high mortality.

Even though the understanding of the pathogenesis of COVID-19 is still incomplete, the

central role of the immune response in determining the development of severe clinical

pictures is increasingly being defined. Organ damage could therefore not be induced by the

direct effect of the infection, but mediated by an uncontrolled immune response resulting in

the development of a "cytokine storm", as suggested by the high levels of inflammatory

cytokines (among which interleukin 6 (IL-6), tumor necrosis factor (TNF) and interferon γ

(IFNγ) play a major role) in patients who exhibit severe or fatal disease. To date, no drug

has been approved with a specific indication for the treatment of COVID-19. The current

treatment encompasses antiviral agents approved for other viral infections, including

protease inhibitors (lopinavir and ritonavir), anti-influenza drugs (oseltamivir and arbidol)

and compassionate use of nucleotide analogues. Several studies are evaluating the possible

effectiveness of the inhibition of pro-inflammatory cytokines activity in preventing or

treating severe COVID-19, through the use of immunomodulators (chloroquine and

hydroxychloroquine) or monoclonal antibodies such as tocilizumab, which targets the IL-6

receptor. Despite promising preliminary results, a multitude of patients need an immediate

treatment while the results of ongoing clinical trials are awaited.


Although most COVID-19 infections resolve spontaneously without the need for specific

therapy, up to 20% of patients can develop severe clinical pictures with

interstitial-alveolar pneumonia characterized by dyspnoea, tachypnea and hypoxemia up to an

acute respiratory distress syndrome (ARDS), severe respiratory failure and multi-organ

dysfunction requiring ICU hospitalization and burdened with high mortality.

To date, the pathogenesis of SARS-CoV-2 pneumonia is poorly understood, but the

immune-inflammatory response to infection is progressively emerging as pivotal in the

development of severe clinical manifestations. An adequate viral load might stimulate the

immune cells to synthesize pro-inflammatory cytokines as interleukin 1 and 6 (IL-1, IL-6),

tumor necrosis factor α (TNF α) and attract macrophages, responsible for the secretion of

several chemokines that could trigger an unregulated "cytokine storm". A few reports of

histological analysis of lung tissue specimens from COVID-19 patients highlighted nonspecific

inflammatory changes with the appearance of edema, hyaline membranes and an inflammatory

infiltrate dominated mainly by lymphocytes. Peripheral blood tests often reveal

lymphocytopenia and a high neutrophil count are found, especially in case of severe disease,

with a high value of neutrophil to lymphocyte ratio (NLR), and a relevant increase in

circulating pro-inflammatory cytokines levels.

While vaccines and drugs directly targeting the virus are currently being developed and are

not yet available, preventing the excessive and uncontrolled cytokine release and

inflammatory response could be the key to avoid the occurrence of severe disease.

Different clinical trials are exploring this path, evaluating immunomodulators and monoclonal

antibodies targeting mediators such as interleukin 6(IL-6).

Although conventionally fractionated (1.8-2 Gy/fraction) and hypofractionated (> 3 Gy

fraction) radiotherapy, used in the field of neoplastic diseases, provides its therapeutic

effect also inducing pro-inflammatory molecules, it has widely been documented in the first

decades of the last century that low-dose radiotherapy (LD-RT) is potentially effective and

relatively safe in the control of acute and/or chronic inflammatory diseases (e.g. skin

diseases such as psoriasis, necrotizing abscesses, tendonitis, impingement syndrome).

Many studies reported the effectiveness of radiation treatment after a single application,

with a prompt improvement of symptoms, usually occurring within 24 ours and often definitive

or long-lasting. Low dose radiotherapy exerts its effect on several cells involved in the

immune response: endothelial cells, polymorphonuclear leukocytes, lymphocytes and

macrophages. This is true also for pneumonia.

Endothelial cells play a crucial role in the inflammation process, both for the "homing"

process of leukocytes, and for the expression of a wide variety of cytokines and growth

factors. Different studies have shown that a dose of 0.5 Gy induces an over-expression of

tumor growth factor β (TGF-β), which has immunosuppressive activity and leads to a reduction

in leukocyte adhesion on endothelial cells.

The leukocyte "rolling" on the endothelium in the sites where inflammation is present

represents the initial step of the inflammatory cascade. The effects of LD-RT were analyzed

in vitro; after radiation doses of 0.3 - 0.6 Gy, there was a 25-40% reduction in adhesion

compared to control after 24 hours from irradiation.

Ionizing radiation at doses below 1 Gy are also capable to polarize macrophages towards the

M2 anti-inflammatory phenotype. Conversely, doses greater than 1 Gy tend to induce

polarization towards the M1 pro-inflammatory subtype. The use of low doses of radiation seems

to act on macrophages also reducing their cytotoxic action, reducing the production of nitric

oxide (NO) through to the inhibitory action on the enzyme cytokine inducible nitric oxide

synthetase (iNOS) .

Neutrophils play a central role in lung damage induced by Middle East Respiratory Syndrome

(MERS) and SARS-CoV, and likewise in COVID-19, as they migrate into the alveoli where they

release proteinases and trigger the innate response, with consequent development of cell

damage and clinical presentations like ARDs (30,31). Low-dose radiation therapy is able to

initiate the apoptotic process of polymorphonuclear granulocytes (neutrophils), thus reducing

their cytotoxic activity (32). This treatment can therefore exert an anti-inflammatory

activity through several mechanisms of action, with an optimal and long lasting effect

demonstrated for a dose of 0.5 Gy (32).

In the absence of a specific treatment, while ongoing trial are evaluating pharmacological

approaches and vaccines, innovative approaches could be undertaken to face the emergency and

allow a satisfactory management of the disease.

A single fraction radiation treatment delivering low doses to the entire bilateral lung

parenchyma (whole lung treatment) is a reasonable and conceptually valid option to inhibit

inflammation and obtain a prompt improve of the symptoms in the short term.

Unlike most of the drugs analyzed so far in the framework of COVID-19 infection, low dose

radiotherapy is characterized by a minor risk of side effect (negligible, considering the

acute phase) and could therefore represent an optimal complementary therapeutic approach due

to its safety and absence of interaction with pharmacological treatments. Moreover, this

treatment requires less than one hour including treatment planning and administration.


The patient will undergo radiation treatment on both lungs in a single session. From the

physical-dosimetric point of view, the treatment plan will be calculated in an isocentric

manner. The isocenter will be positioned at a depth of 10 cm with respect to an anterior skin

landmark specifically defined during CT-scan acquisition. The treatment plan will be

elaborated using a field in field irradiation technique, with 2 beams each one composed by 3

beamlets: one conformed to the volume resulting by the union of the lungs with a 2 cm margin,

the other two will be obtained by shielding the spine and alternately one lung each. This set

up allows to obtain a dose distribution in which the vertebral bodies receive a dose lower

than 55 cGy with an average lung dose of 70 cGy and maximum lungs dose lower than than 90

centigray (cGy). The Pinnacle ® treatment planning system (TPS) with Collapsed Convolution

calculation algorithm will be used. Prescription doses were determined according to data and

indications currently published and optimized to minimize the dose to the vertebrae.


Radiation: Single fraction whole lung radiotherapy
Participants will undergo irradiation of the lungs, administered in a single fraction at the average prescription dose of 0.7 Gy
Lung low dose radiotherapy

Eligibility Criteria

Inclusion criteria - Age ≥ 50 years - Patients with confirmed diagnosis of SARS-Cov2 infection by RT-PCR on nasopharyngeal swab and / or bronchoalveolar lavage (BAL) - Patient with Brescia Covid Respiratory Severity Scale (BCRSS) score 2-3 - Suggestive picture finding for interstitial pneumonia on chest X-ray and / or chest CT (optional) - At least 3 of the following laboratory criteria: - PCR> 5 times the maximum limit of the normal value - Ferritin> 500 ng / ml - lactate dehydrogenase (LDH) > 2 times the maximum limit of the normal value - D-dimer> 3 times the maximum limit of the normal value - Aspartate aminotransferase (AST)> 2 times the maximum limit of the normal value - Total lymphocytes

Eligibility Gender
Eligibility Age
Minimum: 50 Years

Stefano M Magrini, Prof

Davide Tomasini, MD

Stefano M Magrini, Prof
Principal Investigator
Brescia University - ASST Spedali Civili Hospital

Azienda Socio Sanitaria Territoriale degli Spedali Civili di Brescia
NCT Number
MeSH Terms