MPN-111 SVR (Spleen Volume Reduction) Predicts OS (Overall Survival) in MF (Myelofibrosis) Patients on PAC (Pacritinib) but Not BAT (Best Available Therapy): PERSIST-2 Landmark OS Analysis

JAK2 inhibitors can reduce spleen volume in MF patients, and SVR is considered a surrogate for disease response. Ruxolitinib (RUX) cannot be administered at full dose in patients with low platelets (PLTs), and it is not known whether SVR is associated with survival benefit in such patients. PAC is a...

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Published in:Clinical lymphoma, myeloma and leukemia myeloma and leukemia, 2023-09, Vol.23, p.S382-S383
Main Authors: Ajufo, Helen, Bewersdorf, Jan Philipp, Harrison, Claire, Palandri, Francesca, Mascarenhas, John, Palmer, Jeanne, Gerds, Aaron, Kiladjian, Jean-Jacques, Buckley, Sarah, Derkach, Andriy, Roman-Torres, Karisse, Rampal, Raajit
Format: Article
Language:English
Subjects:
JAK2
MPN
myelofibrosis
pacritinib
spleen volume
survival
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Summary:JAK2 inhibitors can reduce spleen volume in MF patients, and SVR is considered a surrogate for disease response. Ruxolitinib (RUX) cannot be administered at full dose in patients with low platelets (PLTs), and it is not known whether SVR is associated with survival benefit in such patients. PAC is a JAK2/IRAK1/ACVR1 inhibitor that was studied in MF patients with PLTs ≤100×109/L in the PERSIST-2 study, in which PAC demonstrated a significant SVR benefit vs BAT (including RUX). Here we present a retrospective analysis of the relationship between SVR and OS in patients with cytopenic MF. This analysis includes PERSIST-2 patients in the study at the start of the 12-week SVR window who received PAC 200 mg BID or BAT. OS was evaluated among SVR responders vs non-responders using different SVR thresholds (≥35%, ≥20%, ≥10%, >0%) and a landmark analysis methodology. OS curves were compared using the log-rank test. SVR ≥10% was associated with a significant survival benefit on PAC. This threshold demonstrated the greatest separation in OS curves between responders (n=65) and non-responders (n=24), with no deaths among responders vs 5 among non-responders (P0% and SVR ≥20% were also associated with improved survival on PAC. While SVR ≥35% is a standard response threshold, it was a less predictive indicator of survival on PAC (P=0.3516), as many patients with SVR
ISSN:2152-2650
2152-2669
DOI:10.1016/S2152-2650(23)01218-1