The SOLIDARITY Finland Plus Long-COVID is the long-term follow-up of the SOLIDARITY
Finland Plus trial. With local adjustments, this clinical trial follows the WHO core
protocol. SOLIDARITY Finland (Plus) is an adaptive, randomized, open-label clinical trial
evaluating the safety and efficacy of imatinib, infliximab, and local standard of care in
hospitalized adult patients diagnosed with COVID-19.)

Study population:

The study population consists of adult patients (18 years and older) with
laboratory-confirmed SARS-2-CoV-2, who are admitted to the hospital ward or the intensive
care unit (ICU). Adult hospital patients, with definite COVID-19 and, as per the
responsible doctor, no contraindication to the study drugs were entered into the online
electronic data collection system and randomly allocated (1:1:1, if no contraindications)
between:

1. the local standard of care alone or

2. local standard of care plus oral imatinib (until discharge or up to 14 days) or

3. local standard of care plus a single intravenous infusion of infliximab.

Exclusion criteria:

There are several drug-specific exclusion criteria. Contraindications to be randomized to
the infliximab study arm include tuberculosis, hepatitis B, severe bacterial infection,
unstable cardiac insufficiency, multiple sclerosis, or hypersensitivity to infliximab, or
previous regular use of biological medication with immunomodulatory effects.
Contraindications to be randomized to imatinib include hepatitis B, liver cirrhosis, and
hypersensitivity to imatinib.

In addition to drug-specific exclusion criteria, the trial also has several general
exclusion criteria. These include very poor prognosis due to comorbidity ( an estimated
less than three months life expectancy), ASAT/ALAT-ratio over five-fold the upper limit,
severe renal failure (GFR < 30), acute myocardial infarction or unstable angina pectoris,
pregnancy or breastfeeding.

Hospitalized patients are recruited from August 2021 onwards in participating hospitals
to the SOLIDARITY Finland Plus trial. During patient recruitment and before
randomization, the following data are to be collected (via the WHO database):

1. hospital and randomizing doctor

2. confirmation that patient has provided consent

3. patient identifiers, age, and sex

4. major comorbidities, including diabetes, heart disease, chronic lung disease,
chronic liver disease, asthma, HIV infection, obesity

5. hospitalization date

6. COVID severity by

1. possible respiratory support: no oxygen, low-flow oxygen, high-flow nasal
oxygen, non-invasive ventilation, invasive ventilation, and ECMO.

2. SpO2 (%) and respiratory rate.

7. Imaging abnormalities.

8. Locally available study drugs.

Consent:

All prospective patients for the long-term follow-up have already consented to SOLIDARITY
Finland Plus during their hospital stay. In the SOLIDARITY Finland Plus Long-COVID,
patients will receive, by mail, an information letter, consent form, and questionnaires.
The mail will be sent three days before the three follow-up time points, which are at six
months, one, and two years. Patients may reply by i) sending back the completed
documents, ii) scheduling a phone call with an investigator for an interview, or iii)
declining participation. If the patient does not reply in 21 days (from the day the
investigators sent the questionnaire to the patient), the investigators will send one
reminder by mail and, if there will not be a reply, then the investigators will approach
the patient via telephone at around 14 (12-15) days from the reminder mail. The phone
call will be attempted twice: during and after office hours. If the patient does not
answer the phone, the investigators will also send a text message to inform them about
the reason for our attempted phone call.

Questionnaire (symptoms and characteristics):

Our multidisciplinary team of clinicians, methodologists, and patient partners developed
a questionnaire that records basic patient information. This questionnaire has already
been in use with the long-term follow-up of patients who received remdesivir in the
SOLIDARITY Finland trial. The questions include i) date of completing the questionnaire,
ii) age, iii) height and weight, iv) smoking status (never, ex-smoker, current smoker),
v) possible comorbidities, and whether diagnosed before or after COVID-19-infection
(obstructive sleep apnea, stroke, coronary artery disease, diabetes, hypertension,
cancer, and any psychiatric disease), vi) employment (student, unemployed, employed,
sickness allowance, retired), vii) working capability in comparison to the pre-COVID-19
state, viii) physician visits due to symptoms associated with COVID-19, ix)
physician-diagnosed long-COVID-19 syndrome. Questionnaires will also document long-term
symptoms. Relevant long-COVID-19 -symptoms (in total 20) were identified from recent
publications and review articles. This same questionnaire will be used at one and two
years. Exertional and cardiopulmonary symptoms potentially related to COVID include
fatigue, postexertional malaise, dyspnea during exercise, chest discomfort, palpitations,
cough, and respiratory mucous discharges. Main neuropsychiatric symptoms potentially
related to COVID include generalized fatigue, attention and memory deficits, sleeping
difficulties, depression and anxiety, dizziness, and even sensory disturbances such as
paresthesias and changes in taste or smell perceptions. Other commonly encountered
symptoms potentially related to COVID include widespread pains (muscle and joint pains,
headache), skin rash, nausea, and fever. The burden from each individual symptom is an
ordinal variable and will be graded from 0 to 3, where 0 represents no symptom, 1
represents mild bother, 2 moderate bother, and 3 severe bother due to the symptom.
Dyspnea is assessed in accordance with the Modified Medical research council dyspnea
scale (mMRC) from 0 to 4, where 0 represents dyspnea only with strenuous exercise, and 4
the presence of dyspnea even with mild physical activity, e.g., dressing clothes. To
capture the dimensions of recovery, the investigators will use the Core Outcome Measure
for Recovery, which has been recommended for use in COVID-19 research.

Quality of life:

The investigators have obtained permission from EuroQol to use the EQ-5D-5L questionnaire
to record the patient's QoL. EQ-5D-5L assesses the domains of mobility, self-care, usual
daily activities, general pain/discomfort, anxiety/depressions, and an overall impression
of health. The first five domains are graded from 1 to 5, while the last uses the visual
analogue scale from 0 to 100. Due to our multiethnic patient population, the
questionnaires have been translated into the following languages: Albanian, Arabic,
English, Estonian, Farsi, Finnish, Russian, Somali, and Swedish. The above-mentioned
questionnaire (Finnish language version as the original) has also been translated into
these languages.

Data security and future use of data:

Patient information will be encrypted and held securely by the Sponsor. Those analyzing
it will use only pseudonymized data, and no identifiable patient details will appear in
publications. Data from questionnaires will also be analyzed using pseudonymized data.
The investigators have taken care to limit the questions to necessary and clinically
relevant aspects related to long COVID.

Primary outcome variables:

i) Symptoms: Each 20 symptoms between the two treatment arms will be compared. These are
measured as follows; each range from 0 to 3 (0 = No symptom. 1 = Symptom exists and
causes small bother. 2 = Symptom exists and causes moderate bother. 3 = Symptom exists
and causes severe bother.) ii) QoL: Using the EQ-5D-5L to compare domain-specific scores
between the two treatment arms.

Additional variables (at 1 or 2 years; depending on future funding and ethical approval
decisions; currently the study has ethical approval for long-COVID and quality of life
assessments only):

- Registry data: Mortality data will be obtained from Digital and Population Data
Services Agency (Finnish Digital Agency)). Underlying causes of death will be
obtained from Statistics Finland and classified according to the International
Statistical Classification of Diseases and Related Health Problems, 10th revision).
In line with the Finnish regulations, any consent will not be required from the
study patients to acquire information on their census data, vital status, and causes
of death for registry research purposes. Comorbidity will be obtained from Finnish
Institute for Health and Welfare THL. These will be performed through linkage the
patient national identification number to registry records. This study is unlikely
well-powered to measure changes in mortality; however, being aware of the vital
status is important for the overall follow-up of study participants.

- Spirometry parameters are continuous variables as absolute values (liters = L;
liters per second = L/s), percentage of reference values, and z-values. These
include VC, FVC, FEV1, FEV1/VC, peak expiratory flow (PEF), the maximal expiratory
flow at 50 % (MEF50), and the forced expiratory time (FET). Spirometry will be
performed with a bronchodilator test to assess the changes between baseline and
after bronchodilation. Diffusing capacity parameter DLCO is a continuous variable
with ml/min/mmHg as the unit.

- Entire genomes will be sequenced to identify single-nucleotide polymorphisms that
would associate with long-COVID symptoms and the effect of imatinib or infliximab.

Subgroup analyses:

For the primary outcomes, a priori planned subgroup analysis will be performed for
whether the patient needed oxygenation at hospital admission (the investigators
hypothesize that the treatment effect is larger for those without extra oxygen than those
with extra oxygen at hospital admission).

Comparisons between the two treatment arms will be performed as follows:

- Descriptive statistics: Descriptive statistics will be presented with numbers and
percentages for categorical variables and means, standard deviation, and range for
continuous variables. In the case of clearly skewed continuous variables, they will
be presented with median, interquartile range (25th and 75th percentiles), and
range. Demographics and baseline characteristics will be presented with descriptive
statistics without any hypothesis testing.

- Continuous variables will be subject to repeated measures mixed models or
appropriate non-parametric alternatives.

- Binary response variables will be analyzed using logistic regression (possibly
adjusting for within-subject dependencies by generalized estimating equations or
mixed models) or chi-square/Mantel-Haenszel tests.

- If missing data is regarded as having a significant effect on the conclusions of the
trial, sensitivity analyses with different methods for handling missing data will be
included.