Patients with myeloid malignancies bearing PDGFRB fusion genes achieve durable long-term remissions with imatinib

Abstract

Key Points• Imatinib achieves deep and durable remissions in patients with myeloid neoplasms bearing PDGFRB.• Allogeneic stem cell transplantation is no longer indicated for patients with chronic myeloproliferative neoplasm bearing PDGFRB who respond to imatinib.Myeloid neoplasms and eosinophilia with rearrangements of PDGFRB are uncommon Philadelphia-negative myeloproliferative neoplasms. Patients are typically male, with morphologic features of a Philadelphia-negative chronic myeloproliferative syndrome or chronic myelomonocytic leukemia with eosinophilia. Reciprocal translocations involving PDGFRB result in fusion genes with constitutively activated receptor tyrosine kinase sensitive to inhibition with imatinib. We present an updated and expanded analysis of a cohort of 26 such patients treated with imatinib. After a median follow-up of 10.2 years (range, 1.8-17 years), the 10-year overall survival rate was 90% (95% confidence interval, 64%-97%); after median imatinib duration of 6.6 years (range, 0.1-12 years), the 6-year progression-free survival rate was 88% (95% confidence interval, 65%-96%). Of the patients, 96% responded; no patients who achieved a complete cytogenetic (n 5 13) or molecular (n 5 8) remission lost their response or progressed to blast crisis. Imatinib is well-tolerated and achieves excellent long-term responses in patients with PDGFRB rearrangements. (Blood. 2014;123(23):3574-3577)

How I treat hypereosinophilic syndromes

“…76 Complete and durable remission was reported in .80% of subjects in a recent case series of 26 patients. 77 Due to rarity of PDGFRBassociated MPN, there are only anecdotal or no data on imatinib dosing, resistance, or treatment interruption.…”

Circulating aberrant plasma cells allow risk stratification of patients with myeloma

“…In a recent report by Cheah et al [9], 3 among 26 patients with PDGFRB-rearranged neoplasms discontinued imatinib: two of them were non-responders or intolerant and the other one received allogeneic stem cell transplantation. Excluding the aforementioned post-transplant case, to our knowledge this is the first report describing a patient with PDGFRB-rearranged neoplasm experiencing a long-term remission after imatinib discontinuation.…”

Chronic myeloid leukemia: reminiscences and dreams

“…In this review, we discuss the various milestones in the study, diagnosis, monitoring and treatment of CML, and speculate on the notion of cure and candidates for future therapy. 10 …”