Treatment of Myelodysplastic Syndrome (MDS)
MDS treatment is fundamentally determined by risk stratification using IPSS-R (or IPSS-M when available), with higher-risk patients receiving hypomethylating agents (HMAs) or allogeneic stem cell transplantation, while lower-risk patients receive supportive care with targeted therapies for cytopenias. 1
Risk Stratification Framework
Before initiating treatment, risk stratification using IPSS-R is required 1. The IPSS-R categorizes patients into very low, low, intermediate, high, and very high-risk groups based on:
- Cytogenetic abnormalities
- Bone marrow blast percentage
- Hemoglobin level
- Platelet count
- Absolute neutrophil count
IPSS-R intermediate-risk patients require individualized assessment based on their specific score: those with IPSS-R ≤3.5 can be managed as lower-risk, while those >3.5 should be treated as higher-risk 2.
Higher-Risk MDS Treatment Algorithm
Fit Patients ≤70 Years with Donor Available
Allogeneic stem cell transplantation (allo-SCT) is the only curative option and should be offered to all higher-risk MDS patients ≤70 years without major comorbidities 1. This includes:
- HLA-matched sibling or unrelated donors
- Haploidentical donors as acceptable alternatives
- Cord blood (less commonly)
Key transplant considerations:
- Patients <55 years without comorbidities should receive myeloablative conditioning 1
- Reduced-intensity conditioning (RIC) is appropriate for older patients or those with comorbidities, though relapse risk is higher
- When bone marrow blasts are >10%, cytoreduction with HMAs or chemotherapy before transplant is generally recommended, especially for non-myeloablative approaches 1
- Iron chelation should be initiated early in transplant candidates, as even moderate iron overload increases transplant-related mortality 1
Patients >70 Years or Without Donor
Azacitidine is the first-line standard of care for higher-risk MDS patients not eligible for transplant 1.
Dosing regimen:
- Azacitidine 75 mg/m²/day subcutaneously for 7 consecutive days every 28 days
- Alternative "5-2-2" regimens are acceptable and often more practical
- Minimum of 6 cycles required before assessing response, as most patients respond after several courses 1
- Oral decitabine/cedazuridine can substitute for IV decitabine in patients with IPSS Intermediate-1 and above 2
Emerging combination therapy: The 2025 NCCN guidelines now include HMAs combined with venetoclax as a treatment option for both transplant and non-transplant candidates with higher-risk MDS 2. However, this requires careful patient selection due to:
- Significant neutropenia (39%) and thrombocytopenia (39%)
- Febrile neutropenia (17-34%)
- Not yet FDA-approved for MDS (used off-label)
AML-Like Intensive Chemotherapy
Reserved for fit patients (generally <70 years) with favorable cytogenetics (especially normal karyotype) and >10% marrow blasts, preferably as a bridge to allo-SCT 1.
Critical caveat: Patients with unfavorable karyotype show poor complete response rates and should NOT receive intensive chemotherapy 1.
Suggested regimens include cytarabine with idarubicin or fludarabine 1.
Very Frail Patients
Supportive care only:
- RBC transfusions
- Antibiotics for infections
- Platelet transfusions as needed
- Consider clinical trials if available 1
Lower-Risk MDS Treatment Algorithm
The primary goal in lower-risk MDS is managing cytopenias (especially anemia) and improving quality of life, not necessarily prolonging survival 1.
First-Line Treatment for Anemia
Patients WITHOUT del(5q):
Erythropoiesis-stimulating agents (ESAs) are first-line therapy 1:
- EPO alpha 30,000-80,000 units weekly OR darbepoetin 150-300 mcg weekly
- Response rate: 40-60% when baseline EPO <200-500 U/L and minimal/no transfusion requirement
- ESAs are an independent favorable prognostic factor for survival 1
- G-CSF can be added to improve efficacy 1
- Target hemoglobin: 10-12 g/dL, not to exceed 12 g/dL 2
Patients WITH del(5q):
Lenalidomide is the most effective first-line treatment for transfusion-dependent anemia in lower-risk MDS with del(5q) 1:
- Initial dose: 10 mg/day for 21 out of 28 days or 28 days monthly for 2-4 months to assess response 2
- Use caution with low platelet/neutrophil counts; dose modification may be needed
Second-Line Treatment After ESA Failure
For MDS with ring sideroblasts (MDS-RS):
- Luspatercept is recommended 1
For other lower-risk MDS after ESA failure:
- Antithymocyte globulin (ATG) with cyclosporine has efficacy in younger patients with specific characteristics 1
- Lenalidomide + ESA combination 1
- Low-dose HMAs (azacitidine or decitabine) have shown clinical benefit in some studies 2, 1
Important note: TPO receptor agonists (romiplostim, eltrombopag) have some efficacy for severe thrombocytopenia but are NOT approved for MDS and should only be used in patients with marrow blasts <5% 1.
Supportive Care Considerations
Iron Chelation Therapy
Strongly recommended for:
- All candidates for allo-SCT, even with moderate iron overload 1
- Non-transplant candidates with lower-risk MDS who have major iron overload (significantly reduced cardiac T2* on MRI) 1
Consider starting when:
- Received 20-60 RBC concentrates
- Serum ferritin >1000-2500 U/L
- Cardiac T2* <20 milliseconds on CMR imaging (associated with decreased left ventricular ejection fraction) 1
Agent: Deferasirox (oral) is preferred over parenteral deferoxamine; cannot be used in renal failure 1.
Treatment Failure Management
Treatment failure is defined as no response within 3-6 months 2. Response should be evaluated using IWG criteria.
When lower-risk MDS fails to respond to initial therapy, escalate to higher-risk management strategies 2.
For higher-risk MDS failing HMAs: Median survival is <6 months. Options include:
- Clinical trials (preferred)
- Allo-SCT if eligible
- Mutation-targeted therapies if specific mutations present (IDH1/2 with olutasidenib or ivosidenib) 2
Special Populations and Emerging Therapies
IDH1-mutated MDS: The 2025 NCCN guidelines note that olutasidenib monotherapy achieved 33% overall response, and combination with azacitidine achieved 69% response in intermediate- to very-high-risk MDS 2.
Imetelstat was approved in 2024 for transfusion-dependent lower-risk MDS 3.
Critical pitfall: Many combination studies with HMAs have been completed, but none have proven superior to single-agent azacitidine in phase III trials 4, 3. Use combinations cautiously and preferably in clinical trial settings.