PB0745 - Platelet count trajectory post treatment in high risk MDS; Does it help in response assessment?

Background: The recent use of hypomethylating agents (HMA) in conjunction with the Bcl-2 inhibitor venetoclax (VEN) has been one of the promising advancements in the treatment of high-risk myelodysplastic syndromes (MDS). Platelet count (PC) has been identified as a significant predictor for treatment response and survival. In our region none of the studies have been conducted reporting the prognostic significance of PC after receiving VEN-HMA therapy.

Aims: We analyzed pre and post treatment PC and evaluated its association with treatment response and overall survival (OS).

Methods: We analyzed 19 high risk MDS patients who received 6 cycles of HMA i.e. decitabine or azacitidine, along with VEN. Chi square, Mann Whitney U test and Kaplan Meier survival analysis were performed.

Results: Transfusion dependence was observed in 16(84%) patients pre-treatment which was resolved in 8(42%) patients and reduced in 3(16%) patients post-treatment. Overall, 8(42%) deaths were reported, and CR was achieved in 7(37%) patients. Median PC at baseline of alive and patients who expired was 27x 10^9/L and 23x 10^9/L (p=0.275). However, after treatment alive patients had higher PC than expired (122 vs 40, p=0.012). Similarly, complete and non-responders had the same PC before treatment (p=0.303) while complete responders had higher PC than non-responders post-treatment (184 vs 18, p= 0.001). The increment in PC post treatment in the patient groups with PC < 50 x10^9/L and >50 x10^9/L was found non-significant (82 x10^9/L vs 101x 10^9/L, p=0.75). The achievement of CR in the platelet category was also found non-significant (p=0.634).

Conclusion(s): Our study revealed that platelet recovery after HMA-VEN treatment was associated with CR and lower mortality rate. In amalgamation with cytogenetics, FLT3 and ECOG status; PC could be a significant predictor for prognosis and could indirectly assess the treatment response particularly in older patients.