Magnitude of response with myeloma frontline therapy does not predict outcome: Importance of time to progression in southwest oncology group chemotherapy trials
ABSTRACT Four Southwest Oncology Group (SWOG) standard-dose chemotherapy protocols for multiple myeloma (MM) initiated between 1982 and 1992 were evaluated. The purpose was to clarify the predictive value of specific levels of myeloma-associated monoclonal protein reduction and time to first progression using mature data sets.
Study data on 1,555 eligible previously untreated patients with MM enrolled onto SWOG phase III trials 8229, 8624, 9028, and 9210 were used in these analyses. Six-month and 12-month landmark analyses were performed to evaluate the outcome for patients in each response category.
The overall and event-free survivals for the four protocols combined were 33 months and 18 months, respectively. Using 6- and 12-month landmarks, the median survivals of 30 to 35 months were not different for responders (> or = 50% and > or = 75% regression) versus nonresponders in patients without disease progression before the landmarks. Conversely, at the 6- and 12-month landmarks, the median survivals for patients who had experienced disease progression were 13 and 15 months, respectively, versus a 34-month median for patients who did not experience progression. Using the Cox survival model, with response and progression considered as time-dependent covariates, survival duration was influenced more by the occurrence of progression than by the occurrence of response.
The magnitude of response, as a single variable, does not predict survival duration. Patients with response and stable disease have equivalent outcome. Only patients with progressive disease have a poorer outcome. The best indicator of survival is time to first progression.
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ABSTRACT: Acute myeloid leukemia-initiating cells (LICs) are responsible for the emergence of leukemia and relapse after chemotherapy. Despite their identification more than 15 years ago, our understanding of the mechanisms responsible for their self-renewal activity and their chemoresistance remains poor. The slow progress in this area is partly due to the difficulty of studying these cells ex vivo. Indeed, current studies are reliant on xenotransplantation assays in immunodeficient mice. In this paper, we report that by modeling key elements of the bone marrow niche using different stromal feeder layers and hypoxic culture conditions, we can maintain LICs over at least 3 weeks and support their self-renewal properties demonstrated through primary and secondary successful xenograft. We provide a proof of principle that this niche-like culture system can be used to study LIC chemoresistance following in vitro cytarabine treatment similarly to the xenograft chemotherapy model. We found that although LICs are believed to be more chemoresistant than non-LICs, functionally defined LICs are not enriched after cytarabine treatment, and heterogeneity in their resistance to treatment can be seen between patients and even within the same patient. We present a culture system that can be used as an in vitro surrogate for xenotransplantation and that has the potential to dramatically increase the throughput of the investigation of LICs. This would further provide the means by which to identify and target the functionality of the different signaling pathways involved in the maintenance and resistance of LICs to improve acute myeloid leukemia treatments.STEM CELLS TRANSLATIONAL MEDICINE 02/2014; DOI:10.5966/sctm.2013-0166 · 3.60 Impact Factor
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ABSTRACT: To evaluate the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging (MRI) to discriminate between symptomatic and asymptomatic myeloma in lumbar bone marrow without visible focal lesions. The lumbar spine was examined with 3-T MRI in 11 patients with asymptomatic myeloma and 24 patients with symptomatic myeloma. The fat-signal fraction was calculated from the ratio of the signal intensity in the fat image divided by the signal intensity of the corresponding ROI in the in-phase IDEAL image. The t test was used to compare the asymptomatic and symptomatic groups. ROC curves were constructed to determine the ability of variables to discriminate between symptomatic and asymptomatic myeloma. Univariate analysis showed that β2-microglobulin and bone marrow plasma cell percent (BMPC%) were significantly higher and fat-signal fraction was significantly lower with symptomatic myeloma than with asymptomatic myeloma. Areas under the curve were 0.847 for β2;-microglobulin, 0.834 for fat-signal fraction, and 0.759 for BMPC%. The fat-signal fraction as a biomarker for multiple myeloma enables discrimination of symptomatic myeloma from asymptomatic myeloma. The fat-signal fraction offers superior sensitivity and specificity to BMPC% of biopsy specimens.PLoS ONE 02/2015; 10(2):e0116842. DOI:10.1371/journal.pone.0116842 · 3.53 Impact Factor