The MDS Beacon™

Revlimid (lenalidomide) has been used since 2005 to treat myelodysplastic syndromes (MDS) patients who need red blood cell transfusions, or have deletion 5q syndrome and Low- or Intermediate-1 risk MDS.

Although the drug was initially perceived to be equally effective across all risk categories and for all deletion 5q patients, recent research has shown that the baseline prognosis of various chromosome 5 abnormalities is different.  This is expected to affect the way Revlimid is prescribed for these conditions, including deletion 5q and monosomy 5.

Patients with deletion 5q syndrome have a significant deletion in the long arm of chromosome 5. This condition most frequently occurs in young female Low-risk MDS patients who need red blood cell transfusions, have anemia (low red blood cells counts), and have normal or average platelet counts. In the condition known as monosomy 5, patients lack one entire chromosome 5. Abnormalities on chromosome 5 are found in 20 percent of all MDS patients.

Revlimid, a structurally similar analog of thalidomide, was first approved by the U.S. Food and Drug Administration after a study showed that MDS patients responded positively.  Although the exact mechanism of Revlimid has yet to be fully characterized, it is believed to affect the genes that direct the cell’s growth and activity, particularly those associated with cytokines, cell death, and metabolism.

Results showed that 66 percent of Revlimid-treated patients became independent of red blood cell transfusions, while 44 percent of patients in the study showed a complete response.  Complete response is defined by the International Working Group as having a blood count of more than 1,000 neutrophils per µL and more than 100,000 platelets per µL.  Patients had a median remission length of 116 weeks.  The drug has been determined as non-curative, but is used to delay or prevent progression to acute myeloid leukemia (AML), a type of blood cancer.

Since the drug was first approved for treating MDS, the potential benefits or effects on the specific subgroups of MDS patients with chromosome 5 abnormalities has not been studied until recently.

Researchers from the M.D. Anderson Cancer Center in Houston investigated the baseline prognoses of MDS patients without Revlimid treatment.  They demonstrated that there are different prognoses even among patients who have abnormalities on chromosome 5.  In addition, results showed that median survival progressively worsened with increased numbers of additional chromosomal abnormalities.

Researchers concluded that those with deletion 5q generally had lower-risk MDS than those with monosomy 5, and that they should not be treated as one group.  This may help oncologists offer Revlimid to patients whose prognoses predict improvement, rather than to those who may not benefit from the treatment.

For more details about the study, please see the related MDS Beacon article or the study in the journal Cancer (abstract).