Acalabrutinib Study With Best Supportive Care in Participants Hospitalized With COVID-19

Inclusion Criteria:

1. Participant or legally authorized representative must be able to understand the
purpose and risks of the study and provide written informed consent and authorization
to use protected health information (in accordance with national and local patient
privacy regulations).

2. Participants who are hospitalized with coronavirus (SARS-CoV-2) infection, confirmed
by PCR test or other commercial or public health assay in any specimen, as documented
by either of the following:

1. PCR positive in sample collected < 72 hours prior to first dose, OR

2. PCR positive in sample collected ≥ 72 hours prior to first dose (but no more than
14 days prior to first dose), documented inability to obtain a repeat sample (eg,
due to lack of testing supplies, limited testing capacity, results taking > 24
hours, etc), AND progressive disease suggestive of ongoing SARS-CoV-2 infection 3
Evidence of respiratory failure attributable to COVID-19 pneumonia (documented
radiographically) before enrollment 4 Nasogastric tube or other types of oral or
percutaneous gastric feeding tube; placement must be radiographically confirmed
and expected to remain in place, as judged by the investigator, for a minimum of
3 days after study enrolment.

5 Has received treatment with PPIs (eg, omeprazole, esomeprazole, lansoprazole,
dexlansoprazole, rabeprazole, or pantoprazole) for a minimum of 24 hours
immediately prior to enrollment; any PPI will be permitted, provided it meets the
minimum equivalent daily dose of 20 mg rabeprazole.

Exclusion Criteria:

1. Any serious and uncorrectable medical condition or abnormality of clinical
laboratory tests that, in the Investigator's judgment, precludes the
participant's safe participation in and completion of the study.

2. In the opinion of the Investigator, progression to death is imminent and
inevitable within the next 24 hours, irrespective of the provision of
treatments.

3. Current refractory nausea and vomiting, malabsorption syndrome, disease
significantly affecting gastrointestinal function, resection of the stomach,
extensive small bowel resection that is likely to affect absorption,
symptomatic inflammatory bowel disease, partial or complete bowel
obstruction, or gastric restrictions and bariatric surgery, such as gastric
bypass.

4. Received BTK inhibitor within 7 days before enrollment.

5. Requires or is receiving anticoagulation with warfarin or equivalent vitamin
K antagonists (eg, phenprocoumon) within 7 days prior to enrollment. Other
anticoagulants are permitted.

6. Participants on dual antiplatelet and therapeutic anticoagulant therapy (eg,
aspirin and therapeutic doses of low molecular weight heparin are not
allowed; however, aspirin and prophylactic/ low doses of
low-molecular-weight heprin are allowed).