Leukemia
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Waldenström's Macroglobulinemia (WM) is a rare disease of the elderly with a median age of 63-68 years at diagnosis. Despite recent progress in biological insights and therapeutics, WM remains clinically challenging to diagnose and is difficult to manage with significant morbidity and lack of established curative therapies. ⋯ Recent scientific work in this field has also guided the identification of new targets such as CXCR4 and PI3K-delta that may have major implications in the future treatment of WM. This review discusses the role of MYD88 L265P mutations as well as targets beyond MYD88 in the setting of pathogenesis and development of future rational therapeutic trials focusing on patients diagnosed with WM.
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MYD88 L265P is highly prevalent in Waldenstrom's Macroglobulinemia (WM) and IgM monoclonal gammopathy of unknown significance (MGUS). We investigated whether MYD88 L265P could be identified by peripheral blood (PB) allele-specific PCR. MYD88 L265P was detected in untreated WM (114/118; 96.6%); previously treated WM (63/102; 61.8%); and IgM MGUS (5/12; 41.7%) but in none of 3 hyper-IgM or 40 healthy individuals. ⋯ For positive patients, PB MYD88 L265P ΔCt was <6.5 in 100/114 (88%) untreated WM, and >6.5 in 4/5 (80%) IgM MGUS patients (P=0.0034). Attainment of a negative PB MYD88 L265P mutation status was associated with lower BM disease (P=0.001), serum IgM (P=0.019) and higher hemoglobin (P=0.004) levels in treated patients. These studies show the feasibility for detecting MYD88 L265P by PB examination, and the potential for PB MYD88 L265P ΔCt use in the diagnosis and management of WM patients.
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Multicenter Study
Replacement of bortezomib with carfilzomib for multiple myeloma patients progressing from bortezomib combination therapy.
In this open-label, intra-patient phase I/II trial, bortezomib was replaced with carfilzomib (escalated from 20 to 45 mg/m(2) on days 1, 2, 8, 9, 15 and 16 of a 28-day cycle) for multiple myeloma (MM) patients who progressed while on or within 12 weeks of receiving a bortezomib-containing combination regimen. Study objectives included determination of the maximum tolerated dose (MTD), overall response rate (ORR), clinical benefit rate (CBR), time to progression, time to response, duration of response, progression-free survival and overall survival (OS). Of 38 registered patients, 37 were treated and evaluable for efficacy and safety. ⋯ Nonhematologic AEs (⩾grade 3) included fever (5.4%) and hypokalemia (5.4%). These results demonstrate that replacing bortezomib with carfilzomib is safe and can be effective for MM patients failing bortezomib-containing combination regimens. This trial was registered at http://www.clinicaltrials.gov (#NCT01365559).