BCR-ABL transcript dynamics support the hypothesis that leukemic stem cells are reduced during imatinib teatment

PurposeImatinib induces a durable response in most patients with Philadelphia chromosome-positive chronic myeloid leukemia, but it is currently unclear whether imatinib reduces the leukemic stem cell (LSC) burden, which may be an important step toward enabling safe discontinuation of therapy. In this article, we use mathematical models of BCR-ABL levels to make inferences on the dynamics of LSCs.Experimental designPatients with at least 1 BCR-ABL transcript measurement on imatinib were included (N = 477). Maximum likelihood methods were used to test 3 potential hypotheses of the dynamics of BCR-ABL transcripts on imatinib therapy: (i) monoexponential, in which there is little, if any, decline in BCR-ABL transcripts; (ii) biexponential, in which patients have a rapid initial decrease in BCR-ABL transcripts followed by a more gradual response; and (iii) triexponential, in which patients first exhibit a biphasic decline but then have a third phase when BCR-ABL transcripts increase rapidly.ResultsWe found that most patients treated with imatinib exhibit a biphasic decrease in BCR-ABL transcript levels, with a rapid decrease during the first few months of treatment, followed by a more gradual decrease that often continues over many years.ConclusionsWe show that the only hypothesis consistent with current data on progenitor cell turnover and with the long-term, gradual decrease in the BCR-ABL levels seen in most patients is that these patients exhibit a continual, gradual reduction of the LSCs. This observation may explain the ability to discontinue imatinib therapy without relapse in some cases.Andrew M. Stein, Dean Bottino, Vijay Modur, Susan Branford, Jaspal Kaeda, John M. Goldman, Timothy P. Hughes, Jerald P. Radich, and Andreas Hochhau

Venglustat, a Novel Glucosylceramide Synthase Inhibitor, in Patients at Risk of Rapidly Progressing ADPKD: Primary Results of a Double-Blind, Placebo-Controlled, Phase 2/3 Randomized Clinical Trial

Rationale & Objective: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of multiple kidney cysts that leads to growth in total kidney volume (TKV) and progression to kidney failure. Venglustat is a glucosylceramide synthase inhibitor that has been shown to inhibit cyst growth and reduce kidney failure in preclinical models of ADPKD. Study Design: STAGED-PKD was a 2-stage, multicenter, double-blind, randomized, placebo-controlled phase 2/3 study in adults with ADPKD at risk of rapidly progressive disease, who were selected based on Mayo Clinic imaging classification of ADPKD class 1C, 1D, or 1E and an estimated glomerular filtration rate (eGFR) of 30-89.9 mL/min/1.73 m2. Setting & Participants: Enrollment included 236 and 242 patients in stages 1 and 2, respectively. Interventions: In trial stage 1, the patients were randomized 1:1:1 to venglustat, 8 mg; venglustat, 15 mg; or placebo. In stage 2, the patients were randomized 1:1 to venglustat, 15 mg (highest dose identified as safe and well tolerated in stage 1), or placebo. Outcomes: Primary end points were rate of change in TKV over 18 months in stage 1 and eGFR slope over 24 months in stage 2. Secondary end points were eGFR slope over 18 months (stage 1), rate of change in TKV (stage 2), and safety/tolerability, pain, and fatigue (stages 1 and 2). Results: A prespecified interim futility analysis showed that venglustat treatment had no effect on the annualized rate of change in TKV over 18 months (stage 1) and had a faster rate of decline in eGFR slope over 24 months (stage 2). Due to this lack of efficacy, the study was terminated early. Limitations: The short follow-up period after the end of treatment and limited generalizability of the findings. Conclusions: In patients with rapidly progressing ADPKD, treatment with venglustat at either 8 mg or 15 mg showed no change in the rate of change in TKV and a faster rate of eGFR decline in STAGED-PKD despite a dose-dependent decrease in plasma glucosylceramide levels. Funding: This study was funded by Sanofi. Trial Registration: Registered at ClinicalTrials.gov with study number NCT03523728

The STAGED-PKD 2-Stage Adaptive Study With a Patient Enrichment Strategy and Treatment Effect Modeling for Improved Study Design Efficiency in Patients With ADPKD

Rationale & Objective: Venglustat, a glucosylcer-amide synthase inhibitor, inhibits cyst growth and reduces kidney failure in mouse models of autosomal dominant polycystic kidney disease (ADPKD). STAGED-PKD aims to determine the safety and efficacy of venglustat and was designed using patient enrichment for progression to end-stage kidney disease and modeling from prior ADPKD trials.Study Design: STAGED-PKD is a 2-stage, international, double-blind, randomized, placebo -controlled trial in adults with ADPKD (Mayo Class 1C-1E) and estimated glomerular filtration rate (eGFR) 45-<90 mL/min/1.73 m2 at risk of rapidly progressive disease. Enrichment for rapidly progressing patients was identified based on retrospective analysis of total kidney volume (TKV) and eGFR slope from the combined Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease and HALT Progression of Polycystic Kidney Disease A studies.Setting & Participants: Target enrollment in stages 1 and 2 was 240 and 320 patients, respectively.Interventions: Stage 1 randomizes patients 1:1:1 to venglustat 8 mg or 15 mg once daily or placebo. Stage 2 randomizes patients 1:1 to placebo or venglustat, with the preferred dose based on stage safety data.Outcomes: Primary endpoints are TKV growth rate over 18 months in stage 1 and eGFR slope over 24 months in stage 2. Secondary endpoints include: annualized rate of change in eGFR from baseline to 18 months (stage 1); annualized rate of change in TKV based on magnetic resonance imaging from baseline to 18 months (stage 2); and safety, tolerability, pain, and fatigue (stages 1 and 2).Limitations: If stage 1 is unsuccessful, patients enrolled in the trial may develop drug-related adverse events that can have long-lasting effects.Conclusions: Modeling allows the design and powering of a 2-stage combined study to assess venglustat's impact on TKV growth and eGFR slope. Stage 1 TKV assessment via a nested approach allows early evaluation of efficacy and increased efficiency of the trial design by reducing patient numbers and trial duration.Y

Venglustat, an orally administered glucosylceramide synthase inhibitor: Assessment over 3 years in adult males with classic Fabry disease in an open-label phase 2 study and its extension study

International audienceVenglustat inhibits the enzymatic conversion of ceramide to glucosylceramide, reducing available substrate for the synthesis of more complex glycosphingolipids. It offers a potential new approach to the treatment of patients with Fabry disease (α-Gal A deficiency), in whom progressive accumulation of such glycosphingolipids, including globotriaosylceramide (GL-3), in the lysosomes of a wide range of cell types often leads to vital organ complications in adulthood. An international, open-label, single-arm, Phase 2a uncontrolled 26-week clinical study (NCT02228460) and a 130-week extension study (NCT02489344) were conducted to assess the safety, pharmacodynamics, pharmacokinetics, and exploratory efficacy of 15 mg once daily oral venglustat in treatment-naïve adult male patients with classic Fabry disease. Of 11 patients (18–37 years old) who initially enrolled, nine completed the 26-week study and seven completed the extension study. A total of 169 treatment-emergent adverse events (TEAEs) were reported by nine patients, the majority being mild (73%) and unrelated to the study drug (70%). Nine serious TEAEs (serious adverse events) and 11 severe TEAEs, including a self-harm event, were reported. No deaths or treatment-related life-threatening adverse events were reported. Skin GL-3 scores in superficial skin capillary endothelium (SSCE), estimated by light microscopy, were unchanged from baseline at Week 26 in five patients, decreased in three patients, and increased in one patient. There was no significant change in GL-3 scores or significant shift in grouped GL-3 scores. Five of six patients had reductions from baseline in GL-3 score at the end of the extension study. At Weeks 26 and 156 the mean (standard deviation) changes from baseline in the fraction of the volume of SSCE cytoplasm occupied by GL-3 inclusions, measured by electron microscopy unbiased stereology, were − 0.06 (0.03) (p = 0.0010) and − 0.12 (0.04) (p = 0.0008), respectively. Venglustat treatment reduced markers in the synthetic and degradative pathway of major glycosphingolipids; proximal markers reduced rapidly and more distal markers (plasma GL-3 and globotriaosylsphingosine) reduced progressively. There were no biochemical or histological indications of progression of Fabry disease over 3 years of follow-up. These findings confirm target engagement and the pharmacodynamic effects of venglustat in adult males with classic Fabry disease. However, further clinical evaluation in larger studies is needed to determine efficacy and safety

Long-term prognostic significance of early molecular response to imatinib in newly diagnosed chronic myeloid leukemia: an analysis from the International Randomized Study of Interferon and STI571 (IRIS)

This study examines the prognostic significance of early molecular response using an expanded dataset in chronic myeloid leukemia patients enrolled in the International Randomized Study of Interferon and STI571 (IRIS). Serial molecular studies demonstrate decreases in BCR-ABL transcripts over time. Analyses of event-free survival (EFS) and time to progression to accelerated phase/blast crisis (AP/BC) at 7 years were based on molecular responses using the international scale (IS) at 6-, 12-, and 18-month landmarks. Patients with BCR-ABL transcripts > 10% at 6 months and > 1% at 12 months had inferior EFS and higher rate of progression to AP/BC compared with all other molecular response groups. Conversely, patients who achieved major molecular response [MMR: BCR-ABL (IS) ≤ 0.1%] by 18 months enjoyed remarkably durable responses, with no progression to AP/BC and 95% EFS at 7 years. The probability of loss of complete cytogenetic response by 7 years was only 3% for patients in MMR at 18 months versus 26% for patients with complete cytogenetic response but not MMR (P < .001). This study shows a strong association between the degree to which BCR-ABL transcript numbers are reduced by therapy and long-term clinical outcome, supporting the use of time-dependent molecular measures to determine optimal response to therapy. This study is registered at www.clinicaltrials.gov as NCT00006343

High Resolution Discovery Proteomics Reveals Candidate Disease Progression Markers of Alzheimer’s Disease in Human Cerebrospinal Fluid

<div><p>Disease modifying treatments for Alzheimer’s disease (AD) constitute a major goal in medicine. Current trends suggest that biomarkers reflective of AD neuropathology and modifiable by treatment would provide supportive evidence for disease modification. Nevertheless, a lack of quantitative tools to assess disease modifying treatment effects remains a major hurdle. Cerebrospinal fluid (CSF) biochemical markers such as total tau, p-tau and Ab42 are well established markers of AD; however, global quantitative biochemical changes in CSF in AD disease progression remain largely uncharacterized. Here we applied a high resolution open discovery platform, dMS, to profile a cross-sectional cohort of lumbar CSF from post-mortem diagnosed AD patients versus those from non-AD/non-demented (control) patients. Multiple markers were identified to be statistically significant in the cohort tested. We selected two markers SME-1 (p<0.0001) and SME-2 (p = 0.0004) for evaluation in a second independent longitudinal cohort of human CSF from post-mortem diagnosed AD patients and age-matched and case-matched control patients. In cohort-2, SME-1, identified as neuronal secretory protein VGF, and SME-2, identified as neuronal pentraxin receptor-1 (NPTXR), in AD were 21% (p = 0.039) and 17% (p = 0.026) lower, at baseline, respectively, than in controls. Linear mixed model analysis in the longitudinal cohort estimate a decrease in the levels of VGF and NPTXR at the rate of 10.9% and 6.9% per year in the AD patients, whereas both markers increased in controls. Because these markers are detected by mass spectrometry without the need for antibody reagents, targeted MS based assays provide a clear translation path for evaluating selected AD disease-progression markers with high analytical precision in the clinic.</p></div