Treatment of newly diagnosed multiple myeloma patients with a combination of cyclophosphamide (Cytoxan), Velcade (bortezomib), and dexamethasone (Decadron) (abbreviated CyBorD) appears to be effective and safe. The findings were presented June 5 in a poster session at the American Society of Clinical Oncology (ASCO) annual meeting.

The study compared CyBorD with Revlimid (lenalidomide)-dexamethasone treatment (abbreviated RD) and cyclophosphamide-Revlimid-dexamethasone treatment (abbreviated CRD). The results of the Phase 2 trials indicate that RD and CyBorD treatment were similar in efficacy and safety. CRD, however, was not as effective and had more severe side effects than RD and CyBorD.

All drugs included in the trials have been approved for use in multiple myeloma by the United States Food and Drug Administration. RD as well as Velcade-dexamethasone are commonly used to treat newly diagnosed myeloma patients. This study shows that the addition of cyclophosphamide may increase the efficacy of the Velcade regimen, but not the Revlimid regimen.

A total of 150 patients were enrolled in the trials, including 40 who were considered high risk due to chromosomal abnormalities.

The average number of cycles completed during the trial varied by regimen, with RD patients staying on therapy the longest (patients completed a median of four cycles CyBorD, eight cycles RD, or five cycles CRD). Following completion of treatment, patients in the CyBorD and RD groups responded much better than those in the CRD group, with near complete response rates of 41 percent, 35 percent, and 11 percent, respectively.

Survival was similar among the treatment groups, with overall median progression-free survival of 2.6 years and 2-year overall survival of 87 percent to 95 percent. However, 3-year survival was significantly longer in patients who subsequently received a stem cell transplant (95 percent survival) as compared to those who did not (75 percent).

Regardless of treatment regimen, high-risk patients experienced earlier relapse than standard-risk patients. Fifty percent of high-risk patients experienced two years without disease progression as opposed to 70 percent of standard-risk patients.

Fewer patients receiving CyBorD (8 percent) and RD (9 percent) experienced severe complications as compared to patients receiving CRD (25 percent). However, 58 percent of CyBorD patients experienced peripheral neuropathy (tingling and pain in the extremities often associated with Velcade therapy), a rate much higher than in the RD (20 percent) and RCD (13 percent) groups.

The researchers concluded that CyBorD treatment resulted in superior response rates and similar or fewer side effects than treatment with RD and CRD. However, they noted, “At this time, improved early depth of response does not translate into different survival outcomes.” They are encouraged, though, by the fact that 82 percent of patients enrolled in the trial have survived four years since treatment.

For more information, see abstract 8131 on the ASCO meeting website.