Combined differentiating therapy for myelodysplastic syndromes: a phase II study

Area of Science:

• Hematology
• Oncology
• Pharmacology

Background:

• Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders.
• Previous in vitro studies indicated synergistic effects between different inducers of AML cell differentiation.
• Current MDS treatments have limitations, necessitating exploration of novel therapeutic approaches.

Purpose of the Study:

• To evaluate the efficacy and safety of a combination therapy for myelodysplastic syndromes (MDS).
• To assess the response rates, duration of response, and survival outcomes in MDS patients treated with cis-retinoic acid and cholecalciferol.

Main Methods:

• A total of 53 myelodysplastic syndrome (MDS) patients were treated with a low-dose combination of cis-retinoic acid (cRA) and 1,25 alpha (OH)2 cholecalciferol [(OH)2D3].
• Intermittent 6-thioguanine was added for patients with bone marrow (BM) blast excess (≥5%).
• Patients were stratified based on BM blast percentage (<5% or ≥5%) to assess treatment response and survival.

Main Results:

• The combination therapy was well-tolerated with no major toxicity observed.
• In patients with <5% BM blasts, the overall response rate was 52% (1 CR, 8 PR, 4 MR) with a median response duration of 8 months.
• In patients with ≥5% BM blasts, the response rate was 61% (1 CR, 12 PR, 6 MR), and responders showed significantly improved survival (median 25 months vs. 9 months for non-responders, P < 0.005).
• A reduction in transfusion needs was observed in 41-53% of transfusion-dependent patients.

Conclusions:

• Combined differentiating therapy using cis-retinoic acid and cholecalciferol appears more effective than previously reported single-agent treatments for MDS.
• The observed survival benefit in patients with blast excess warrants further investigation.
• This combination therapy should be considered for larger randomized studies to confirm its impact on MDS patient survival.