What is the treatment for primary autoimmune thrombocytopenia (Immune Thrombocytopenia Purpura, ITP)?

Treatment of Primary Autoimmune Thrombocytopenia (ITP)

Corticosteroids are the standard first-line treatment for newly diagnosed primary ITP patients, with prednisone typically given at 0.5-2 mg/kg/day until platelet counts increase to 30-50 × 10⁹/L. 1

First-Line Treatment Options

Corticosteroids

• Prednisone: 0.5-2 mg/kg/day until platelet count increases (30-50 × 10⁹/L)

  • Response rate: 70-80% initially
  • Time to response: Several days to weeks
  • Should be rapidly tapered and stopped after 4 weeks to avoid complications 1

• Dexamethasone: 40 mg/day for 4 days (equivalent to 400 mg prednisone/day)

  • Can be given in 1-4 cycles every 14 days
  • Higher initial response rate (up to 90%)
  • Sustained response in up to 50-80% of patients
  • May be superior to prednisone based on recent studies 1

• Methylprednisolone: 30 mg/kg/day for 7 days

  • Response rate up to 95%
  • Faster response than prednisone (4.7 days vs 8.4 days)
  • 23% sustained response at 39 months 1

Other First-Line Options

• Intravenous Immunoglobulin (IVIG): 1 g/kg as one-time dose

  • For patients with clinically significant bleeding or requiring rapid platelet increase
  • Response rate >80% within 24-48 hours
  • Associated with black box warning for thrombosis and renal failure 2

• IV anti-D: 50-75 μg/kg (for Rh(D) positive, non-splenectomized patients only)

  • Response similar to IVIG
  • Time to response: 4-5 days
  • Main side effect: hemolytic anemia 1

Treatment Algorithm Based on Clinical Presentation

1. For non-bleeding patients with platelet count >30 × 10⁹/L:

   • No treatment needed, observation only 2

2. For patients with platelet count <30 × 10⁹/L without significant bleeding:

   • Short course of corticosteroids (preferably dexamethasone 40 mg/day for 4 days) 1, 2

3. For patients with active bleeding or need for procedures:

   • IVIG (1 g/kg) or IV anti-D (if Rh positive) for rapid platelet increase
   • Can be combined with corticosteroids 1, 2

Second-Line Treatment Options

For patients failing first-line therapy (non-responders or relapse):

1. Thrombopoietin Receptor Agonists (TPO-RAs):

   • Romiplostim: Weekly SC injections, individualized dosing (1-10 μg/kg)
   • Demonstrated efficacy in both splenectomized and non-splenectomized patients
   • Durable platelet responses in 38-61% of patients 3, 4

2. Rituximab (anti-CD20):

   • Standard dose: 375 mg/m² weekly for 4 weeks
   • Response in approximately 60% of patients 4, 5

3. Splenectomy:

   • Historically effective with approximately two-thirds of patients achieving normal platelet counts
   • Consider after failure of medical management
   • Permanent solution but carries surgical risks 4, 6

4. Immunosuppressive agents:

   • Azathioprine, cyclosporine, mycophenolate mofetil
   • Used to facilitate corticosteroid reduction 2, 5

Monitoring and Follow-up

• Weekly platelet count monitoring during dose adjustment
• Monthly monitoring after establishing stable dose
• Follow-up with hematologist within 24-72 hours of discharge 2

Important Considerations and Pitfalls

• Avoid prolonged corticosteroid use to prevent significant adverse effects (mood swings, weight gain, diabetes, hypertension, osteoporosis, etc.) 1, 2

• Treatment should focus on bleeding symptoms, not just platelet count 2

• Don't delay second-line therapy for patients requiring repeated corticosteroid courses 2

• Consider testing for co-infections like H. pylori and treating if positive 2

• For women with heavy menstrual bleeding, consider antifibrinolytic agents (tranexamic acid) or hormonal medications 2

• Before using IV anti-D, check blood group, DAT, and reticulocyte count; avoid in patients with autoimmune hemolytic anemia 1

• Response criteria vary between studies, making direct comparison of treatment options difficult 1