Duration of Molecular Remission in Patients with Acute Promyelocytic Leukemia (APML) Treated Primarily with Arsenic Tri-oxide

Reviewer: Tracy d'Entremont, MD
OncoLink
Last Modified: December 7, 2002

Presenter: B Georg
Presenter's Affiliation: Christian Medical College; Vellore, India
Type of Session: Poster

Background

Arsenic trioxide (As2O3) has been shown to be very effective for the treatment of APML.
Most data has been with relapsed disease.
Optimal protocols for As2O3 remain to be established.
There are limited data on the duration of molecular remission after treatment with As2O3.

Materials and Methods

All patients presenting between 1/00 and 5/02 who could not receive ATRA due to economic constraints, were given As2O3 as primary therapy for their APML.
As2O3 dose was 10mg daily for adults and 0.15mg/kg/day for children < 15 years old.
Induction therapy was As2O3 daily until hematological CR or maximum of 60 days.
Consolidation therapy was 1 cycle of As2O3 daily for 28 days; one month after the completion of induction therapy.
Maintainence therapy (6 cycles) consisted of As2O3 daily for 10 days each month for a total of 6 months.
Molecular monitoring of PML-RARá transcripts were tested using a nested RT-PCR method at the following times: diagnosis
immediately after induction
just prior to consolidation
twice during maintainence (3mos apart)
every 6 months during follow-up

Results

There were 10 adults and 5 children enrolled
4 patients expired early during induction due to intracranial bleeds
11 patients were evaluable
100% hematological CR rate
100% have completed consolidation therapy and are in hCR with average follow-up of 10 months
1/11 (9%) became PML-RARá negative at time of hCR
9/10 (90%) became PML-RARá negative prior to consolidation therapy without further treatment.
1 patient who remained PML-RARá positive after consolidation therapy became negative during maintainence therapy (at 110 days)
All patients remain PML-RARá at last follow-up.

Author's Conclusions

100% CR with As2O3 among evaluable patients
90% remain + for PML-RARá at the time of achieving hematological CR
90% become PML-RARá negative within 1 month without further therapy
Consolidation/Maintainence therapy is necessary at least in some patients with APML treated with As2O3, but the optimal duration of therapy needs to be determined.

Clinical/Scientific Implications

This small single institution phase II study of As2O3 in APML shows promise in the induction setting. The high incidence of intracranial hemorrhage is noted and should be compared with the incidence in those treated with ATRA and other conventional methods. Future studies are needed to fully define Arsenics role in the treatment of APML.

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