Positive data from Celator's CPX-351 Phase 2 study in newly-diagnosed AML presented at 52nd ASH

Celator Pharmaceuticals today announced positive clinical data in elderly patients with newly-diagnosed acute myeloid leukemia (AML) treated with CPX-351 (Cytarabine:Daunorubicin) Liposome Injection. Data were presented from the podium at the 52^nd American Society of Hematology (ASH) Annual Meeting in Orlando, Florida. The results were based on 12 months of follow-up in a randomized, Phase 2 trial that compared CPX-351 to conventional cytarabine and daunorubicin (the "7+3" regimen), the current standard of care (ASH Abstract #655).

“These encouraging results provide multiple paths for further development of CPX-351, with some patient populations representing opportunities for rapid clinical development and potential product registration”

"Our findings suggest that CPX-351 may provide a long-sought opportunity to improve clinical outcomes over "7+3" in previously untreated AML," said Jeffrey E. Lancet, M.D., associate professor, H. Lee Moffitt Cancer Center, who gave the presentation. "Importantly, these improvements were seen in the overall patient population but were greater in patients with high-risk AML, especially those with secondary AML."

The randomized, open-label Phase 2 study enrolled 126 patients between the ages of 60-75 years with newly-diagnosed AML at 18 sites in the United States and Canada. Patients were stratified as high risk (age 70 or older, secondary AML, or ≥3 chromosomal abnormalities) or standard risk (all other patients). Following randomization, 85 patients received CPX-351 and 41 received the "7+3" regimen.

Compared to patients in the "7+3" arm, patients treated with CPX-351 demonstrated a higher aplasia rate, a higher remission rate (including complete remissions [CR] and complete remissions with incomplete neutrophil/platelet recovery [CRi]), lower induction mortality, improved median event-free survival (EFS), and improved median overall survival (OS).

Follow-up is continuing for another 12 months. Larger improvements over "7+3" were seen in high-risk patients, where median event free survival was 4.5 months versus 1.8 months and median overall survival was 11.0 months versus 7.5 months. Even more noteworthy were the improvements seen in patients with secondary AML treated with CPX-351 who experienced a median event free survival of 3.8 months versus 1.4 months for "7+3" and a statistically significant improvement in median overall survival of 12.1 months versus 6.1 months>

Treatment with CPX-351 was associated with well-characterized and manageable adverse events that were generally comparable to conventional therapy. The myelosuppressive effect of CPX-351 was 7 days and 10 days longer for neutrophil and platelet recovery respectively, than those treated with "7+3," effects consistent with the pharmacokinetics of CPX-351. The frequency and severity of cardiac events was low and similar in both groups.

"These encouraging results provide multiple paths for further development of CPX-351, with some patient populations representing opportunities for rapid clinical development and potential product registration," said Scott Jackson, chief executive officer of Celator Pharmaceuticals. "As we plan for Phase 3, we will continue to collect data from this study until completion of the 24 month follow-up period and look forward to presenting initial results from our second Phase 2 study of CPX-351 in patients with AML in first relapse next year."

Other CPX-351 presentations from the American Society of Hematology Annual Meeting

• CPX-351 in Sequential Therapy for Refractory Leukemia

Results of a Phase 1 trial of sequential treatment for relapsed or primary refractory acute leukemia demonstrated that CPX-351 can be utilized as salvage chemotherapy prior to a reduced intensity conditioning regimen and allogeneic stem cell transplantation (ASH Abstract #1334). Further research is planned to define a maximum tolerated dose of CPX-351 and to shorten the interval between the administration of CPX-351 and the stem cell transplant.

• Activity of CPX-351 Against Human Leukemias

A laboratory evaluation of the cytotoxicity of CPX-351 in 35 patient specimens suggested that CPX-351 possesses potent anti-leukemic activity against a wide range of human leukemia cell types (ASH Abstract #2886). The data establish a rationale for clinical testing of CPX-351 in other leukemia diagnoses besides AML and provide a model for in vitro screening that could help identify specific patient populations most likely to benefit from CPX-351.