Long-term remission after first-line single-agent treatment with arsenic trioxide of relapsed acute promyelocytic leukemia in an 8-year-old boy

Case Report: Very Late, Atypical Extra-Medullary Relapse in a Patient With Acute Promyelocytic Leukemia (APL) Rescued With a Transplant-Free Approach

Relapses of acute promyelocytic leukemia (APL) beyond 7 years from the first molecular remission are exceptional, and it is unclear whether these relapses represent a new, therapy-related leukemia rather than a delayed relapse of the original leukemic clone. The increase extra-medullary relapses (ER) in the era of all-trans retinoic acid (ATRA) therapy suggests a potential correlation between ATRA therapy and ER, and several potential explanations have been proposed. The gold standard post-remission approach, particularly for patients in late relapse, has not yet been established. The benefit of a transplant approach has been questioned in this setting because continuing ATRA-arsenic trioxide (ATO) might be curative. Here we report on the case of an APL patient who relapsed 9 years after achieving her first molecular complete remission (mCR) and who showed an atypical isolated localization at nodal sites, including the into- and peri-parotid glands. Genomic PML/RARa breakpoint analysis detected the same bcr3 PML/RARa hybrid gene in DNA purified from bone marrow and lymph nodes, suggesting that the relapse was because of the reemergence of the initial clone. This case shows that APL, treated with ATRA and cytotoxic drugs, may still emerge in extra-medullary sites even after a very prolonged mCR and could be salvaged with an ATO-based protocol, not including a transplant approach.

Arsenic Trioxide and Icariin Show Synergistic Anti-leukemic Activity

Although As2O3 (ATO) has been recommended as the front-line agent for treatment of acute promyelocytic leukemia (APL), particularly for relapsed or refractory APL, it has been associated with profound toxicity. Icariin is a natural compound with activity against a variety of cancers. This study was designed to investigate the effect of Icariin on APL cells and to determine whether Icariin can potentiate the antitumor activity of ATO in APL cells. Cell proliferation and apoptosis were measured using MTT assay and flow cytometry, respectively. The expression of apoptosis and proliferation-related molecules was detected by Western blotting. Reactive oxygen species (ROS) and mitochondrial membrane potential were determined with florescence staining. Icariin inhibited proliferation in a dose-dependent manner and induced apoptosis in both of the tested APL cell lines. Icariin enhanced the in vitro antitumor activity of ATO against APL. The antitumor activity of Icariin and its enhancement of the antitumor activity of ATO correlated with the increase in accumulation of intracellular ROS. Our results showed that Icariin, by increasing intracellular ROS, exhibited antitumor activity and potentiated the antitumor activity of ATO against APL. Therefore, combination treatment with Icariin and ATO might offer a novel therapeutic option for patients with APL, although further studies are needed.

Treatment of an acute promyelocytic leukemia relapse using arsenic trioxide and all-trans-retinoic in a 6-year-old child

In adult therapy, arsenic trioxide (ATO) and all-trans-retinoic acid (ATRA) are recognized as active treatment of relapsed acute promyelocytic leukemia (APL). The efficacy of this combination in pediatric APL has not yet been well established. We report the case of a 6-year-old girl with relapsed APL, with a PML-RARα mutation, treated with a combination of ATO and ATRA. Over a period of 5 months, she received in total, 75 doses of intravenous ATO and 40 doses of oral ATRA. Currently, 22 months after relapse, she is still in complete remission. Here, we describe treatment of a relapsed APL in a child with limited treatment of ATO and ATRA and review the literature.

Oral arsenic trioxide for relapsed acute promyelocytic leukemia in pediatric patients

Four patients (age 3-11 years at diagnosis) with relapsed acute promyelocytic leukemia (APL), 12-38 months from diagnosis, were treated with oral arsenic trioxide (As(2) O(3) ). One patient was treated with oral As(2) O(3) monotherapy and chemotherapy. Three patients failed initial oral or intravenous As(2) O(3) monotherapy were treated with oral As(2) O(3) plus ATRA followed by long-term oral maintenance (cumulative As(2) O(3) dose 280-2,100 mg). All patients achieved molecular remission, at a median follow up of 122 (10-132) months with no adverse effects. Oral As(2) O(3) , particularly in prolonged maintenance with oral ATRA may obviate the need of stem cell transplantation in relapsed pediatric APL.