Arsenic Trioxide Helpful in Relapsed Promyelocytic Leukemia

By Reuters Staff

NEW YORK (Reuters Health) - In at least half of patients with relapsed acute promyelocytic leukemia (APL), salvage therapy with arsenic trioxide followed by consolidation can lead to a cure, according to European investigators.

In a February 17 online paper in Leukemia, Dr. Eva Lengfelder of University Hospital Mannheim, Germany, and colleagues note that arsenic trioxide is the treatment of choice in such patients but the optimal therapy to sustain arsenic trioxide-induced remission is unknown.

The team examined data from the European registry of APL on 155 patients treated with the agent following their first relapse.

In the 104 patients with hematological relapse, 91% had complete hematological remission (CR) after induction, 7% died during induction and 2% had hematological resistance. In addition, during induction 27% developed APL differentiation syndrome and 39% leukocytosis.

However, in the 40 patients treated in molecular relapse, there were no deaths and no side effects. The rate of molecular CR after consolidation was 74% in hematological relapse and 62% in molecular relapse.

All 11 patients with extramedullary relapse reached molecular remission after consolidation therapy.

At a median 3.2 years of follow-up, the three-year overall survival (OS) came to 68% in hematological relapse and the cumulative incidence of second relapse came to 41%. Corresponding proportions in molecular relapse were 66% and 48%, and in extramedullary relapse they were 90% and 11%.

In the 93 patients in second CR after allogeneic or autologous stem cell transplantation, the three-year overall survival rate was 80% compared with 59% in the 55 patients without transplantation.

Overall, the three-year survival of the 155 patients came to 68%, suggesting, say the investigators "a survival improvement after first relapse of approximately 20% with arsenic trioxide-based salvage therapy by comparison to previous results obtained with all-trans retinoic acid and chemotherapy salvage."

Nevertheless, the relapse rate was still high. Factors associated with a poor prognosis, say the investigators, were remission duration of less than 1.5 years, persistent PCR positivity for promyelocytic leukemia-retinoic acid receptor alpha after consolidation, and not undergoing transplantation.

Dr. Lengfelder did not respond to requests for comments.

SOURCE: https://bit.ly/1Mqzbwf

Leukemia 2015.

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