An Open-Label Extension Study Assessing the Long-Term Efficacy and Safety of ALX-0061 in Subjects With Rheumatoid Arthritis

Inclusion Criteria

• Must have been eligible for one of the preceding Phase IIb studies with ALX-0061 (study ALX0061-C201 or ALX0061-C202), have been randomized to placebo or one of the ALX-0061 arms (subjects randomized to tocilizumab [TCZ] in study ALX0061-C202 were not eligible), and completed the entire treatment and assessment period of the preceding studies (i.e., 24 weeks for study ALX0061-C201 and 12 weeks for study ALX0061-C202).
• Must have reached at least 20% improvement in SJC and/or TJC (66/68 counts) compared to Week 0 at Week 24 for subjects participating in the preceding Phase IIb ALX0061 C201 study, or at Week 12 for subjects participating in the preceding Phase IIb ALX0061-C202 study
• Female subjects of childbearing potential (excluding postmenopausal women, sterilized, ovariectomized, and hysterectomized women) must agree to use 2 generally accepted adequate contraceptive methods of which 1 is a barrier method (e.g., hormonal contraception stabilized for at least 1 month [oral, patch, depot, injectable, vaginal ring] in combination with condom by partner) or should agree upon continuous abstinence from heterosexual contact from screening/baseline until at least 6 months after last dosing. Male subjects must use condoms for the duration of the study and for at least 6 months after last administration of study drug.
• Ability to comprehend and willingness to sign the informed consent form (ICF).
• An understanding of and ability and willingness to adhere to the study visit schedule and other protocol requirements.

Exclusion Criteria

• Received TCZ during the previous Study ALX0061-C202.
• Received any prohibited treatment during the previous Phase IIb studies (ALX0061-C201 or ALX0061-C202.
• Diagnosis of or suspicion of a serious infection (requiring parental antibiotics and/or hospitalization) or tuberculosis during the preceding study.
• Diagnosis of malignancy or demyelinating disease during the preceding study.
• Any active or recurrent viral infection that made the subject unsuitable for the study based on the Investigator's clinical assessment, including recurrent/disseminated herpes zoster.
• Diagnosis of congestive heart failure class III or IV (as defined by the New York Heart Association), unstable angina pectoris, myocardial infarction, and/or cerebrovascular accident during the preceding study.
• Abnormality in laboratory test results observed at the Week 22 visit for subjects participating in the preceding Phase IIb ALX0061-C201 study, or observed at the Week 10 visit for subjects participating in the preceding Phase IIb ALX0061-C202 study:
• Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) levels ≥ 2 times the upper limit of normal (ULN).
• Hemoglobin levels ≤ 85 g/L (8.5 g/dL).
• Platelet count ≤ 75 x 109/L (75,000 cells/mm³).
• Absolute neutrophil count < 1.5 x 109/L.
• Serum creatinine levels ≥ 1.5 mg/dL (133 μmol/L).
• Any other clinically significant abnormal laboratory result as evaluated by the Investigator.
• If no laboratory test results of the Week 22 Visit (for subjects participating in the preceding ALX0061-C201 study) or the Week 10 Visit (for subjects participating in the preceding ALX0061-C202 study) were available, then laboratory values of tests performed between Week 22 and 24 (for study ALX0061-C201) or Week 10 and 12 (for study ALX0061-C202) were taken into account for the exclusion criteria a to e listed above.