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Treatment and the treatment process

Treatment of APL

Acute promyelocytic leukemia (APL) is a special subtype of AML. Its treatment is completely different from other AML types and often does not involve intensive chemotherapy.

Last updated: ~2 min read
On a dark navy background, an immature cell turns step by step into a healthy mature white blood cell.
Figure 1.ATRA helps the APL cell mature.

01Short answer

In APL, leukemia cells get "stuck" at the promyelocyte stage because of a fusion gene called PML::RARA. Treatment is built on two drugs: ATRA (all-trans retinoic acid, a vitamin A derivative) helps the cells mature, and arsenic trioxide breaks down the PML::RARA protein. In low- and intermediate-risk APL this pair is often used without chemotherapy. In high-risk APL (a very high white cell count), chemotherapy or gemtuzumab ozogamicin may be added. The biggest danger is bleeding and clotting problems in the first days, so treatment starts urgently and is supported with blood products.

02Simple explanation

The problem. Cells cannot mature into adult white blood cells.

ATRA. "Reminds" the cells how to mature.

Arsenic trioxide. Removes the protein that drives the disease.

Support. Platelet and plasma transfusions lower the bleeding risk.

03Scientific explanation

Mechanism: the PML::RARA protein disrupts the retinoic acid receptor. High-dose ATRA releases this block, and arsenic trioxide causes the protein to break down (NCI, ELN).

Risk: APL is high risk if the white cell count is above 10×10⁹/L at diagnosis.

Differentiation syndrome: early in treatment, maturing cells can cause inflammation — fever, breathlessness, fluid in the lungs, weight gain. Caught early, it is usually managed with steroids. Arsenic trioxide can prolong the QT interval, so the ECG and electrolytes are monitored.

04What happens in the body?

Why so urgent?

In APL the clotting system is disturbed: the risk of both bleeding and clots rises. So doctors start ATRA as early as possible and try to keep platelets and fibrinogen close to normal.

Glowing scales with platelets on one side and fibrin threads on the other.
Figure 2.At the start of APL, the balance of bleeding and clotting is disturbed.

How does treatment go?

Induction lasts several weeks, usually in hospital. Consolidation courses follow over several months. Figure a shows how the cells mature.

After treatment

Success is checked with a molecular test for the PML::RARA gene. Relapse is rare after molecular remission; your doctor sets the follow-up plan.

Two glowing capsules and a small infusion bag on a dark surface, joined by a golden line.
Figure 3.A combination of two drugs is the core of APL treatment.

05The APL treatment path

A simplified general outline.

Urgent start — ATRA when suspected.1Urgent startATRA when suspected.
Induction — ATRA + arsenic trioxide.2InductionATRA + arsenic trioxide.
Monitoring — ECG, blood, signs of syndrome.3MonitoringECG, blood, signs of syndrome.
Consolidation — Courses over several months.4ConsolidationCourses over several months.
RemissionOften achieved.
Molecular testPML::RARA tracked.
TeamClose monitoring.

06Key elements of APL treatment

ElementPurposeNote
ATRACell maturationTaken by mouth
Arsenic trioxideBreaks down PML::RARAInto a vein; ECG monitoring
Chemotherapy / gemtuzumabAdded in high riskNot needed by everyone
Blood productsPrevent bleedingEspecially in the first days
SteroidsDifferentiation syndromeAs decided by the doctor
Molecular testConfirms remissionBy PCR

* Simplified outline; your doctor chooses the exact plan.

07Key terms

APL
Acute promyelocytic leukemia.
PML::RARA
The fusion gene that causes APL.
ATRA
A vitamin A derivative that helps cells mature.
Arsenic trioxide
A targeted drug used in APL.
Differentiation syndrome
A possible inflammatory reaction early in treatment.
Coagulopathy
A disorder of the clotting system.

08Key points

  • APL needs urgent treatment.
  • The core is ATRA and arsenic trioxide.
  • Often without chemotherapy.
  • The first weeks need the closest care.
  • Report symptoms straight away.
  • Results can be very good.

09Frequently asked questions

Isn’t arsenic a poison?

Medical arsenic trioxide is a proven drug given at an exact dose under monitoring.

Will my hair fall out?

Hair loss is usually minimal with ATRA and arsenic; it may happen if chemotherapy is added.

How long does treatment take?

Induction and consolidation together usually take about 7–9 months.

Would taking vitamin A help?

No. ATRA is a special medicine; do not take vitamins on your own.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Isn’t arsenic a poison?

  2. Will my hair fall out?

  3. How long does treatment take?

  4. Would taking vitamin A help?

My questions

12Sources

  1. National Cancer Institute (NCI). Adult Acute Myeloid Leukemia Treatment (PDQ): APL
  2. American Cancer Society. Treating Acute Myeloid Leukemia (AML)
  3. Cancer Research UK. Acute promyelocytic leukaemia (APL)
  4. Blood Cancer United (LLS). Acute myeloid leukemia (AML) treatment
  5. NHS. Acute myeloid leukaemia: Treatment
  6. European LeukemiaNet. Management of acute promyelocytic leukemia: updated ELN recommendations (Sanz et al., Blood 2019)
  7. American Cancer Society. Chemotherapy for Acute Lymphocytic Leukemia
  8. Cancer Research UK. Chemotherapy
  9. Cancer Research UK. How you have chemotherapy
  10. Cancer Research UK. Side effects of chemotherapy
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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