Arsenic Trioxide (Trisenox) — Clinical FAQs

Question 1

What is Arsenic Trioxide FDA-approved to treat?

Accepted Answer

Arsenic Trioxide is FDA-approved for the following oncology indications: 1. Induction of remission and consolidation in patients with APL who are refractory to, or have relapsed from, retinoid and anthracycline chemotherapy (FDA approved 2000) 2. Newly diagnosed low/intermediate-risk APL (PML-RARα positive) in combination with tretinoin (ATRA) — approved as frontline therapy based on the North American Intergroup C9710 trial and the European APL0406 trial demonstrating superior event-free survival and significantly reduced hematologic toxicity versus ATRA + anthracycline chemotherapy.

Question 2

How does Arsenic Trioxide work (mechanism of action)?

Accepted Answer

Arsenic trioxide exerts multiple complementary mechanisms in acute promyelocytic leukemia (APL). It directly targets the PML-RARα oncoprotein — the product of the t(15;17) translocation — by inducing degradation of the PML portion through SUMOylation and proteasomal destruction, thereby relieving transcriptional repression and permitting partial differentiation of leukemic promyelocytes. At higher concentrations it induces apoptosis via mitochondrial pathways including collapse of the inner mitochondrial membrane potential, cytochrome c release, and caspase-3 activation. Arsenic trioxide also inhibits angiogenesis by downregulating VEGF expression and suppresses the NF-κB pro-survival pathway. These mechanisms are synergistic with all-trans retinoic acid (ATRA), which targets the RARα moiety of the same fusion protein, explaining the striking potency of the ATO + ATRA combination.

Question 3

How is Arsenic Trioxide administered?

Accepted Answer

Arsenic Trioxide is administered Intravenous (IV). Administer as an IV infusion over 1–2 hours (may extend to 4 hours if vasomotor reactions occur); do not administer as a rapid IV push.

Question 4

What are the most common side effects of Arsenic Trioxide?

Accepted Answer

The most commonly reported side effects of Arsenic Trioxide (≥10% incidence) include: Nausea (75%), Cough (65%), Fatigue (63%), Headache (60%), Vomiting (58%) and others (20 total). Consult your oncologist for complete prescribing information.

Question 5

Does Arsenic Trioxide have a black box warning?

Accepted Answer

Yes. Arsenic Trioxide carries FDA black box warning(s) regarding: 1. QTc prolongation and complete heart block / torsades de pointes: Arsenic trioxide causes dose-dependent QTc prolongation that can result in life-threatening torsades de pointes or complete heart block. Obtain a 12-lead ECG and correct electrolyte abnormalities (potassium ≥4.0 mEq/L, magnesium ≥1.8 mg/dL) before initiating therapy. Avoid concomitant QTc-prolonging medications. Monitor ECG at least weekly; if QTc exceeds 500 ms, interrupt therapy, correct all reversible risk factors, and reassess before resuming. 2. APL differentiation syndrome: Arsenic trioxide can cause APL differentiation syndrome (formerly retinoic acid syndrome), which is potentially fatal. Characterized by unexplained fever, dyspnea, weight gain (>5 kg), peripheral edema, pulmonary infiltrates, pleuritis, pericarditis, and hypotension. Treat immediately with dexamethasone 10 mg IV twice daily for at least 3 days or until resolution. Interrupt arsenic trioxide for severe respiratory compromise. The syndrome can occur with or without concurrent leukocytosis.

Question 6

Is Arsenic Trioxide safe during pregnancy?

Accepted Answer

Arsenic Trioxide pregnancy safety: Category D — causes fetal harm. Arsenic trioxide is embryotoxic and teratogenic in animals at doses below the human therapeutic dose. Women of childbearing potential must use effective contraception during treatment; males should also use contraception during and for 3 months after therapy. Breastfeeding is contraindicated.. Oncologists should review the complete prescribing information and discuss reproductive risks with patients before initiating therapy.

Arsenic Trioxide — Drug Monograph

Mechanism of Action

FDA Indications

Common Side Effects

Clinical Pearl

Related Therapies & Mechanisms