Evaluating CPX-351 versus standard chemotherapy for older patients with high-risk acute myeloid leukemia

This study evaluated the effectiveness of CPX-351 (Vyxeos; daunorubicin, cytarabine) versus standard chemotherapy for older patients with high-risk acute myeloid leukemia (AML). This study found that CPX-351 improved long-term outcomes for these patients.

AML is a cancer of the blood and bone marrow. AML can also develop as a secondary cancer (after previous anti-cancer therapy). Combination chemotherapy is the usual first-line treatment for patients with AML. One standard regimen includes cytarabine (Cytosar-U) for 7 days and daunorubicin (Cerubidine) for 3 days (7+3). 

Other medical conditions and poor responses to treatment make AML challenging to treat in patients aged 60 or older. These patients need different treatment options. CPX-351 is a dual-drug agent that delivers both cytarabine and daunorubicin directly to cancer cells. Whether CPX-351 is more effective than standard 7+3 chemotherapy in the long term is under investigation.

This study included 309 patients with high-risk AML. 78 patients had de novo (no history of cancer) AML. 153 patients received CPX-351 (group 1) and 156 patients received standard 7+3 chemotherapy (group 2). Patients who achieved a complete response (no signs of cancer after treatment) were given additional CPX-351 or standard 7+3 chemotherapy as consolidation treatment. This is to help delay the return of cancer. Patients were followed up for an average of 5 years.

At follow-up, more patients in group 1 had a complete response compared to group 2 (48% vs. 33%). Overall, 35 patients who achieved a complete response received consolidation treatment (23 patients in group 1 and 12 patients in group 2). Of these, patients in group 1 survived longer on average compared to group 2 (21.72 months vs. 8.53 months). 

Overall, patients in group 1 survived longer than those in group 2 (9.33 months vs. 5.95 months). Overall, more patients in group 1 were still alive 3 years later (21% vs. 9%) and 5 years later (18% vs. 8%) compared to group 2. CPX-351 was associated with a 30% lower risk of mortality.

Overall, 92 patients had a stem cell transplant after treatment. This included 35% of patients in group 1 and 25% of patients in group 2. Most of these achieved a complete response after the transplant (75% in group 1 vs. 62% in group 2). 3 years later, more patients in group 1 were still alive than in group 2 (56% vs. 23%). CPX-351 increased survival by 49% after a stem cell transplant compared to standard chemotherapy. 

This study found that CPX-351 improved long-term survival compared to standard chemotherapy for older patients with high-risk AML.

This study was open-label, meaning that patients in both groups knew what treatment they received during the study. This study also did not evaluate long-term side effects. More studies are needed to confirm these results and assess the long-term safety of CPX-351. This study was funded by Jazz Pharmaceuticals, the manufacturer of CPX-351.