ADRIA IDARUBICIN APPEARS AS EFFECTIVE AS WYETH-AYERST’s DAUNORUBICIN

ADRIA IDARUBICIN APPEARS AS EFFECTIVE AS WYETH-AYERST's DAUNORUBICIN (Cerubidine) in treating acute nonlymphocytic leukemia (ANLL), FDA's Oncologic Drugs Advisory Committee concluded at its Feb. 2 meeting. "Studies suggest strongly that idarubicin is at least as effective as daunorubicin and probably should be approved," said committee member Teresa Vietti, MD, Pediatric Oncology Group, St. Louis, Missouri. However, the committee's conclusion was based on a preliminary review of available data. The committee, which was not asked to recommend approval for the second generation anthracycline, based its conclusion on an interim analysis of data from three trials comparing idarubicin in combination with cytosine arabinoside to the standard ANLL therapy combination of daunorubicin/cytosine arabinoside (Ara-C). Adria had submitted its final analysis of Phase III data to FDA only four days prior to the committee meeting. Committee member Robert Capizzi, MD, Bowman Gray School of Medicine, North Carolina, emphasized that the committee's opinion is contingent on FDA's analysis of the final data. "If indeed all of the data is in and if indeed all of the data has been appropriately analyzed and if indeed the final analysis is consistent as we have heard this morning, in terms of remission frequency, I think they are comparable." Early in the committee's discussion, members raised questions about the retrospective statistical method used by Adria in evaluating a major study conducted at Memorial Sloan-Kettering Cancer Center on idarubicin's efficacy when compared to daunorubicin. Steven Piantadosi, MD/PhD, Johns Hopkins Oncology Group, asserted that unquestioning acceptance of the company's statistical interpretation of the study would be tantamount to letting them "sneak in the back door." Interim data from the Sloan-Kettering study of 90 ANLL patients found that idarubicin/Ara-C produced a 78% complete response rate compared to 58% for daunorubicin/Ara-C. The company's second study, conducted by the South Eastern Group showed a complete response rate of 68% idarubicin vs. 54% for daunorubicin. An Adria sponsored trial showed equal response rates for the two drugs. None of the trials found a statistically significant improvement in survival for idarubicin over daunorubicin. Several committee members questioned the comparison of idarubicin against daunorubicin given the less than expected efficacy in the daunorubicin arm of the studies. "The Memorial trial that purports to have a superior response rate for the idarubicin trial versus the daunorubicin trial perhaps looks good because the daunorubicin looks so bad," Capizzi suggested. The daunorubicin experience in the trial "had a response rate that was under the national norm," he said. Idarubicin had significantly higher toxicity than daunorubicin in the consolidation phases of the trials. The side effects included: bleeding in 27% of the idarubicin treated patients compared to 21% for daunorubicin; infections in 74% given idarubicin vs. 55% given daunorubicin; and mucositis in 35% given idarubicin vs. 22% given daunorubicin.