Dingli, David

A variety of medications have been implicated in the causation of thrombotic microangiopathy (TMA). Recently, a few case reports have emerged of TMA attributed to the proteasome inhibitors (PI) bortezomib and carfilzomib in patients with multiple myeloma. The aim of this case series was to better characterize the role of PI in the etiology of drug‐induced TMA. We describe eleven patients from six medical centers from around the world who developed TMA while being treated with PI. The median time between medication initiation and diagnosis of TMA was 21 days (range 5 days to 17 months). Median laboratory values at diagnosis included hemoglobin—7.5 g dL−1, platelet count—20 × 109/L, LDH—698 U L−1, creatinine—3.12 mg dL−1. No patient had any other cause of TMA, including ADAMTS13 inhibition, other malignancy or use of any other medication previously associated with TMA. Nine patients had resolution of TMA without evidence of hemolysis after withdrawal of PI. Two patients had stabilization of laboratory values but persistent evidence of hemolysis despite medication withdrawal. One patient had recurrence of TMA with rechallenge of PI. There is a strong level of evidence that PI can cause DITMA. In evaluating patients with suspected TMA, PI use should be recognized as a potential etiology, and these medications should be discontinued promptly if thought to be the cause of TMA. Am. J. Hematol. 91:E348–E352, 2016. © 2016 Wiley Periodicals, Inc.

BACKGROUNDAutologous stem cell transplantation (SCT) is a common management strategy for select patients with immunoglobulin light‐chain amyloidosis, but no trials have documented improved overall survival.METHODSEighty‐nine patients with biopsy‐proven immunoglobulin light‐chain amyloidosis were allowed to select treatment with melphalan plus dexamethasone (n = 34) or SCT (n = 55); all patients were transplant eligible. Treatment preference resulted in imbalanced study arms. Patients who selected SCT were younger, more frequently had an Eastern Cooperative Oncology Group performance status score less than 2, had lower‐stage amyloidosis, and had a lower incidence of cardiac amyloidosis.RESULTSPatients receiving melphalan plus dexamethasone had a 3‐year progression‐free survival rate of 29.1% and an overall survival rate of 58.8%. Patients undergoing SCT had a 3‐year progression‐free survival rate of 51.7% and an overall survival rate of 83.6%. An attempt to match patients between the 2 arms in terms of risk produced 24 matched triplet sets (2 SCT patients for each melphalan‐dexamethasone patient); there was no difference in hematologic response, but there was better survival after autologous SCT. A propensity score–matched analysis of the cohorts (melphalan plus dexamethasone vs SCT) showed an overall mortality hazard ratio of 2.56 (P < .01).CONCLUSIONSAlthough the study had limitations, similar hematologic responses and improved survival were observed after SCT versus melphalan plus dexamethasone. Cancer 2016;122:2197–205. © 2016 American Cancer Society.

Over the past decade, a number of changes have occurred in the diagnostic evaluation, management, and long‐term follow‐up of patients with POEMS syndrome at our institution. This study included 291 patients with POEMS syndrome diagnosed at the Mayo Clinic between 1974 and 2014. Patients diagnosed after 2003 had more features of the syndrome identified at diagnosis and were more likely to receive an autologous transplant (49% versus 8%, P < 0.0001) and to have achieved a hematologic complete response (CR) to treatment (41% vs 25%, P < 0.0001). With 2273 person‐years of follow‐up, 10‐year overall survival (OS) was 62% (95% C.I., 56%, 67%). On multivariate analysis, the three factors associated with superior OS were younger age (RR 0.98 [0.96–1.00]), albumin greater‐than 3.2 g/dL (RR 0.5 [0.32–0.89]) and attainment of complete hematologic response (RR 0.4 [0.2, 0.9]). This study confirms the very good long‐term outcomes of patients with POEMS syndrome and identifies two new prognostic risk factors: albumin at diagnosis and attainment of complete hematologic response. Am. J. Hematol. 91:585–589, 2016. © 2016 Wiley Periodicals, Inc.

A single monoclonal protein typically characterizes monoclonal gammopathies, but a small proportion may have more than one M protein identifiable. In the setting of symptomatic multiple myeloma (MM), the development of a new monoclonal protein following therapy is associated with better outcomes. As for the precursor conditions, monoclonal gammopathy undetermined significance (MGUS) and smoldering multiple myeloma (SMM), there is limited information on the impact of a second monoclonal protein on the disease course, including progression and response to treatment. The outcomes of patients with MGUS and SMM with more than one monoclonal protein, after identifying 539 patients with biclonal proteins on electrophoresis and/or immunofixation, were reported. About 22 of 393 patients with MGUS/biclonal gammopathy of undetermined significance (BGUS) progressed to SMM (6), MM (11), AL (3), or WM (2), and 5 of 16 patients with biclonal SMM progressed to MM. The rate of progression for BGUS was approximately 1% per year, which is similar to MGUS with one monoclonal protein. The median estimated time of progression of biclonal SMM was 2.6 years; similar to monoclonal SMM. For patients with biclonal MM, both M spikes responded to treatment and, upon relapse, the original dominant M protein remained dominant as the disease progressed. In conclusion, the presence of a second monoclonal protein does not appear to affect the progression of precursor states and suggests multiple monoclonal proteins do not clinically impact one another in the course of the disease. Am. J. Hematol. 91:473–475, 2016. © 2016 Wiley Periodicals, Inc.

AbstractCancer, the unregulated proliferation of cells, can occur at any age and may arise from almost all cell types. However, the incidence and types of cancer differ with age. Some cancers are predominantly observed in children, others are mostly restricted to older ages. Treatment strategies of some cancers are very successful and cure is common in childhood, while treatment of the same cancer type is much more challenging in adults. Here, we develop a stochastic model of stem cell proliferation that considers both tissue development and homeostasis and discuss the disturbance of such a system by mutations. Due to changes in population size, mutant fitness becomes context dependent and consequently the effects of mutations on the stem cell population can vary with age. We discuss different mutant phenotypes and show the age dependency of their expected abundances. Most importantly, fitness of particular mutations can change with age and advantageous mutations can become deleterious or vice versa. This perspective can explain unique properties of childhood disorders, for example, the frequently observed phenomenon of a self-limiting leukemia in newborns with trisomy 21, but also explains other puzzling observations such as the increased risk of leukemia in patients with bone marrow failure or chemotherapy induced myelodysplasia.

We investigate the in vivo patterns of stem cell divisions in the human hematopoietic system throughout life. In particular, we analyze the shape of telomere length distributions underlying stem cell behavior within individuals. Our mathematical model shows that these distributions contain a fingerprint of the progressive telomere loss and the fraction of symmetric cell proliferations. Our predictions are tested against measured telomere length distributions in humans across all ages, collected from lymphocyte and granulocyte sorted telomere length data of 356 healthy individuals, including 47 cord blood and 28 bone marrow samples. We find an increasing stem cell pool during childhood and adolescence and an approximately maintained stem cell population in adults. Furthermore, our method is able to detect individual differences from a single tissue sample, i.e. a single snapshot. Prospectively, this allows us to compare cell proliferation between individuals and identify abnormal stem cell dynamics, which affects the risk of stem cell related diseases.

Over the past decade, use of novel agents, including immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs) has resulted in high response rates and improvement in overall survival (OS) for patients with multiple myeloma (MM); however, the prognostic significance of refractoriness to these agents when used as initial therapy has not been extensively studied. We reviewed the outcomes of 816 consecutive patients treated for MM at our institution since 2006 to evaluate the survival difference between those achieving at least a partial response (PR) to induction therapy and those who were primary refractory. The median OS from start of therapy was significantly shorter for the primary refractory group at 3.6 vs. 7.6 years for the responding patients ( P < 0.001). The difference in median OS persisted when only patients receiving a novel agent as part of induction therapy were considered (3.6 vs. 7.9 years, P < 0.001) and in a 4‐month landmark analysis (4.2 vs. 7.6 years, P < 0.001). The median OS for patients achieving a complete response (CR), very good partial response (VGPR), PR, or less than PR was not reached (NR), 6.1, 6.4, and 4.2 years from the 4‐month landmark, respectively ( P < 0.001). The comparatively poor outcomes of patients refractory to induction therapy in the current era of novel agents suggests that this high‐risk subpopulation must be further studied for predictors of resistance and, when identified, should be targeted for clinical trials. Am. J. Hematol. 90:981–985, 2015. © 2015 Wiley Periodicals, Inc.

Response to therapy in newly diagnosed symptomatic multiple myeloma (NDMM) can impact long‐term outcomes. It is not clear if baseline laboratory parameters can predict an early, deep response. Totally 1,304 patients with NDMM seen between 2001 and 2013 at Mayo Clinic Rochester were studied. The association between baseline laboratory parameters and early, deep response defined as a very good partial response or better (VGPR+) within four cycles of treatment was investigated. Multivariable logistic regression was used to assess the associations between the parameters of interest and response. Multivariable proportional hazards regression was used to assess the association between response and overall survival. In the entire cohort, greater absolute free light chain (FLC) differences (OR 2.38, 95% CI 1.48–3.82), younger age (OR 2.18, 95% CI 1.28–3.71), lower hemoglobin (OR 1.68, 95% CI 1.12–2.54), and IgA myeloma (OR 1.66, 95% CI 1.10–2.51) were associated with increased odds of achieving VGPR+ after four cycles. Among patients receiving novel agents in general and immunomodulators in particular, these effects were more pronounced. In patients receiving proteasome‐inhibitors, higher creatinine (OR 3.83, 95% CI 1.37–10.1), lower calcium (OR 3.37, 95% CI 1.36–8.35), and greater absolute FLC differences (OR 2.50, 95% CI 1.10–5.71) were associated with better response. In a landmark analysis at 4 months from diagnosis, achieving VGPR+ was associated with decreased risk of subsequent mortality (HR 0.69, 95% CI 0.53–0.86). In summary, several parameters were associated with an early, deep response to treatment, revealing distinct sets of predictors for immunomodulator‐ and proteasome‐inhibitor‐containing regimens. Achieving VGPR+ after four cycles translated into increased overall survival. Am. J. Hematol. 90:888–891, 2015. © 2015 Wiley Periodicals, Inc.