According to a recent study, myeloma patients with the chromosomal abnormalities del(1p21) or del(17p) had shorter time to disease progression and lower overall survival rates while taking Revlimid-dexamethasone therapy than patients without those abnormalities.

Chromosomal abnormalities result from structural changes of the chromosome.  These changes may occur through deletions, insertions, duplications, or movement of chromosomal regions. Chromosomal abnormalities are considered high-risk factors in multiple myeloma and have been an area of intensive research because they may render patients less responsive to certain treatments.

A series of prior studies have investigated the outcome of myeloma patients with certain chromosomal abnormalities who received Revlimid (lenalidomide)-dexamethasone (Decadron) therapy (see related Beacon news).

The findings of these studies have not, however, been conclusive with regard to the significance of each abnormality. They also have not addressed the outcome of patients with chromosome 1 abnormalities, which are among the most common in myeloma patients.

In their study, the Canadian researchers evaluated the impact of chromosomal abnormalities on patient response to Revlimid-dexamethasone therapy.

They retrospectively analyzed data of 143 relapsed and refractory (treatment resistant) myeloma patients. Laboratory tests were conducted to determine the presence of chromosomal abnormalities.

Overall, the researchers found that 83 percent of patients responded to treatment, with 16 percent achieving a complete or near-complete response.

The researchers also found that only prior thalidomide (Thalomid) treatment, rather than chromosomal abnormalities, had a negative impact on the response rate. The overall response rate among previously thalidomide-treated patients was 76 percent, while 96 percent of patients who did not previously receive thalidomide responded to Revlimid-dexamethasone treatment.

At the median follow-up time of 22 months, 76 percent of patients showed disease progression.  The median time to disease progression was 11 months.

The researchers found that two chromosomal abnormalities were associated with shorter time to disease progression. Patients with del(1p21) had an average time to progression of 4.6 months compared to 13.9 months for patients without del(1p21).  Similarly, patients with del(17p) also had shorter times to progression (2.1 months) than those without it (12 months).

They also found that prior Velcade (bortezomib), thalidomide, and more than three previous therapies led to shorter time to disease progression.

At the last follow-up, the overall survival rate was 48 percent, with an average survival time of 28.2 months.

While patients with del(1p21) or del(17p) generally had shorter survival times (13.6 months and 7.1 months, respectively), the differences were not found to be statistically significant.

The researchers also found that prior Velcade therapy was associated with shorter survival.

The study authors pointed out that larger prospective studies are necessary to confirm their findings.

For more information, please see the article in Leukemia and Lymphoma (abstract).