Safety and Tolerability of MORAb-022 in Healthy and Rheumatoid Arthritis Subjects

Inclusion Criteria for Rheumatoid Arthritis (RA) Subjects:

- Male or female subjects age greater than or equal to 18 years and less than or equal
to 75 years.

- Subjects with RA diagnosis per the 2010 Rheumatoid Arthritis Classification Criteria
per American College of Rheumatology (ACR)/European League Against Rheumatism
(EULAR.)

- BMI less than or equal to 35 kg/m2 at Screening.

- Active RA characterized by DAS28 score of less than or equal to 5.1 at Screening.

- Have been stabilized on their current dose (up to 25 mg/week) of methotrexate(MTX)
for at least 4 weeks before randomization.

Exclusion Criteria for Rheumatoid Arthritis (RA)Subjects:

- Subjects with severe active RA and are not on a stable therapeutic regimen at
Screening.

- Subjects without significant articular RA.

- Relevant history of significant respiratory disease (e.g., chronic bronchitis, asthma
in last 5 years, chronic obstructive pulmonary disease, tuberculosis, interstitial
lung disease, such as pneumonitis and pulmonary alveolar proteinosis, as well as
significant inhalation exposure to silicon and other substances) that required
treatment and/or follow up under the direction of a physician.

- Presence of GM-CSF autoantibodies above normal at Screening.

- Abnormal chest x-ray or PFTs as judged by the investigator at Screening as clinically
significant.

- Positive Quantiferon test.

- History of clinically relevant hypersensitivity reactions (e.g., to gold therapy)

- History of medication use that might have carryover effects during the study.

- Previous administration of a GM-CSF modulator within 6 months of randomization, or
previous administration of a monoclonal antibody or immunoglobulin fusion protein
that is not (or worded as "other than") a GM-CSF modulator within 3 months of
randomization.

- Use of any biological therapy other than the test article during the study (informed
consent to termination visit)

- Subjects who consume greater than 14 alcoholic drinks per week for males or 7
alcoholic drinks per week for females.

- Weight greater than 120 kg at Screening.

- Use of parenteral and/or intra-articular steroids, immunosuppressants,
investigational drugs, and oral anticoagulant drugs within 4 weeks prior to
randomization. Oral steroid treatment is permitted if the dosage is less than or
equal to 10 mg of prednisone daily, is stable for a minimum of 4 weeks before the
study and remains unchanged throughout the study.