The purpose of this study was to compare 2 doses (10 mg and 5 mg) of lenalidomide to that of placebo in subjects with red blood cell (RBC) transfusion-dependent low- or intermediate-1-risk IPSS MDS associated with a deletion (del) 5q[31] cytogenetic abnormality. Study participants were randomized to one of the two treatment groups or to placebo and took the study drug for 16 weeks. At this timepoint, participants were evaluated for erythroid response. If participants did not achieve at least a minor erythroid response, they were discontinued from the Double-Blind phase and entered into the Open-Label phase. All erythroid responders at Week 16 were to continue in the Double-Blind phase for up to 52 weeks. For participants that were still responding at the end of Double-Blind phase, they could then rollover into the Open-Label phase for an additional two years. Participants could remain on study for up to a total of 3 years. All participants who discontinued from the study were followed every 4 months for overall survival and progression to acute myeloid leukemia (AML).

MDS-004 was a multicenter, randomized, double-blind, placebo-controlled, 3-arm study of 2 doses of lenalidomide versus placebo administered to RBC transfusion-dependent adults with low- or intermediate-1 risk MDS associated with a del 5q[31] cytogentetic abnormality. Potential participants that had a del 5q[31] cytogenetic abnormality plus other additional cytogenetic abnormalities were also eligible for enrollment. Transfusion-dependent anemia was defined as documentation that a participant with anemia due to MDS did not have any consecutive 56 days (8 weeks) that were RBC transfusion free during at least the 112 days (16 weeks) prior to Day 1 of the Pre-Randomization Phase.

This study was conducted in three phases:

1. a Pre-Randomization Phase
2. a Double-Blind Treatment Phase
3. an Open-Label Extension Phase

Potentially protocol-eligible participants entered the Pre-Randomization Phase and were evaluated for the inclusion and exclusion criteria for the Double-Blind Treatment Phase. The Pre-Randomization Phase was not to last for more than 56 days (8 weeks). When the participant's baseline RBC transfusion requirement was calculated, and it had been determined that all eligibility criteria had been met, the participant could be randomized for treatment in the Double-Blind Treatment Phase at the time of their next RBC transfusion. This RBC transfusion had to occur within 56 days of the participant's last previous RBC transfusion.

Participants meeting eligibility criteria were randomized (1:1:1 ratio) to receive either lenalidomide 10 mg/day on days 1-21, lenalidomide 5 mg/day on days 1-28, or placebo on days 1-28; all on a 28-day cycle. Randomization was performed using a validated interactive voice response system. Participants were stratified according to karyotype (IPSS karyotype score: 0 vs > 0; i.e., isolated del 5q[31] vs del 5q[31] plus ≥ 1 additional cytogenetic abnormality). A complete blood count (CBC), serum or plasma ferritin, and EPO levels were measured to determine baseline levels.

Participants who achieved at least a minor erythroid response (i.e. 50% decrease in transfusion requirements) by week 16 could continue treatment in the Double-Blind phase for up to 52 weeks, unless there was evidence of erythroid relapse, disease progression, or unacceptable toxicity. Those who did not achieve at least a minor erythroid response by week 16 were discontinued from the Double-Blind phase for lack of therapeutic efficacy, and unblinded and were potentially eligible for Open-Label treatment. All participants who completed the double-blind treatment phase (the first 52 weeks of the trial) without disease progression or erythroid relapse were unblinded and entered the Open-Label extension phase at their current lenalidomide dose. Participants in the placebo or lenalidomide 5 mg arms who failed to achieve at least a minor erythroid response by week 16 or who had an erythroid relapse could cross over to lenalidomide 5 mg or 10 mg, respectively, in the Open-Label Extension phase.

Lenalidomide treatment could be continued in the Open-label Extension phase for up to 3 years (156 weeks) of total study participation. Participants with disease progression at any time and participants in the lenalidomide 10 mg group who did not achieve at least a minor erythroid response by week 16 were withdrawn from the study and were ineligible for Open-Label treatment.

Serial measurements for efficacy and safety were performed every 28 days. In addition, CBCs were monitored weekly for the first 8 weeks, every 2 weeks for the next 8 weeks, and every 4 weeks thereafter. Bone marrow aspirate (BMA) and standard cytogenetic studies were performed at baseline, weeks 12, week 24, and every 24 weeks thereafter and when clinically indicated for assessment of disease progression. BMAs were submitted for central pathology review and sent to a central cytogenetics laboratory for processing and review. All participants were followed for overall survival (OS) and progression to acute myeloid leukemia (AML).

Lenalidomide or placebo dosing was reduced for dose-limiting toxicities according to the following dose reduction schedule:

• Lenalidomide 5 mg (starting dose)

  • dose level -1 (5 mg every other day)
  • dose level -2 (5 mg twice a week)
  • dose level -3 (5 mg weekly)

• Lenalidomide 10 mg (starting dose)

  • dose level -1 (5 mg daily)
  • dose level -2 (5 mg every other day)
  • dose level -3 (5 mg twice a week)

Participants who could not tolerate dose level -3 discontinued treatment. For grade 4 neutropenia, lenalidomide was required per protocol to be interrupted and resumed at a decreased dose level when the absolute neutrophil count (ANC) recovered to ≥ 500/μL. For grade 4 thrombocytopenia, lenalidomide was interrupted and then resumed at a decreased dose level when the platelet count recovered to: between ≥ 25,000/μL and < 50,000/μL on at least 2 occasions for ≥ 7 days; or ≥ 50,000 at any time, respectively. Prophylactic and therapeutic use of granulocyte colony-stimulating factors (G-CSF) or granulocyte macrophage colony-stimulating factors (GM-CSF) was allowed.

Inclusion Criteria:

• Must understand and voluntarily sign an informed consent form
• Age 18 years at the time of signing the informed consent form
• Documented diagnosis of myelodysplastic syndromes (MDS) that meets International Prognostic Scoring System (IPSS) criteria for low to intermediate-1-risk disease and has an associated del 5q(31) cytogenetic abnormality
• Red blood cell (RBC) transfusion dependent anaemia defined as not having any 56 days without a RBC transfusion within at least the immediate 112 days
• Must be able to adhere to the study visit schedule and other protocol requirements
• Women of childbearing potential must have a negative pregnancy test prior to inclusion

Exclusion Criteria:

• Pregnant or lactating females
• Prior therapy with lenalidomide
• Proliferative (white blood cell (WBC)= 12,000/mL) chronic myelomonocytic leukemia (CMML)
• Prior >= grade-2 (using the National Cancer Institute (NCI)'s Common Terminology Criteria for AEs (CTCAE) (v 3.0)) allergic reaction to thalidomide
• Prior desquamating (blistering) rash while taking thalidomide
• Prior history of malignancy other than MDS (except basal cell or squamous cell carcinoma or carcinoma in situ of the cervix or breast) unless the subject has been free of disease for >3 years
• Use of cytotoxic chemotherapeutic agents or experimental agents (agents that are not commercially available) for the treatment of MDS within 28 days
• Less than 6 months since prior allogeneic bone marrow transplantation
• Less than 3 months since prior autologous bone marrow or stem cell transplantation
• Less than 28 days since prior myelosuppressive anticancer biologic therapy
• Recombinant human erythropoietin (rHuEPO) therapy received within 28 days
• Known human immunodeficiency virus (HIV-1) positivity
• Any serious medical condition or psychiatric illness that will prevent the subject from signing the informed consent form or will place the subject at unacceptable risk if he or she participates in the study