Incidence of Monoclonal Gammopathy of Undetermined Significance and Estimation of Duration Before First Clinical Recognition

ObjectivesTo determine the incidence of monoclonal gammopathy of undetermined significance (MGUS) in the general population and to estimate the duration of occult MGUS before first diagnosis.MethodsTo estimate incidence we used innovative methods to exploit the Olmsted County, Minnesota, MGUS prevalence data, along with follow-up from a large cohort of patients with clinically detected MGUS. The prevalence cohort consisted of 21,463 persons systematically screened for the presence or absence of MGUS. The clinical cohort consisted of 7472 patients with MGUS diagnosed at Mayo Clinic from January 1, 1990, to May 13, 2010. The incidence of MGUS was estimated using the prevalence estimates, the rate of MGUS progression, and the death rates from MGUS using Markov chain methods.ResultsWe estimate that the annual incidence of MGUS in men is 120 per 100,000 population at the age of 50 years and increases to 530 per 100,000 population at the age of 90 years. The rates for women are 60 per 100,000 population at the age of 50 years and 370 per 100,000 population at the age of 90 years. We estimate that 56% of women 70 years of age diagnosed as having MGUS have had the condition for more than 10 years, including 28% for more than 20 years. Corresponding values for men are 55% and 31%, respectively. At 60 years of age, the proportion of prevalent cases that are clinically recognized is 13%. This rate increases to 33% at the age of 80 years.ConclusionIn addition to an accumulation of cases, the age-related increase in prevalence of MGUS is related to a true increase in incidence with age. When first clinically recognized, MGUS has likely been present in an undetected state for a median duration of more than 10 years.     

Changes in serum-free light chain rather than intact monoclonal immunoglobulin levels predicts outcome following therapy in primary amyloidosis

Current response criteria for light-chain amyloidosis (AL) relegate FLC response to a subsidiary status relative to serum M-protein response. Given that light chains form the substrate for amyloid fibril formation, we hypothesized that changes in FLC might better predict outcome compared to changes in intact immunoglobulin levels. Two patient cohorts were studied, 347 patients who underwent an autologous stem-cell transplant (SCT) and 96 patients treated with melphalan/dexamethasone. We identified the lowest value following therapy for intact serum M-protein and the difference between involved and uninvolved FLC (FLC-diff). We first examined the relative contribution of M-protein and FLC-diff on the overall survival (OS), and found that FLC reduction, rather than M-protein reduction, significantly impacted OS. The median OS was not reached among those with a 50% decrease in FLC-diff compared to 20 months for the remainder. On regression analysis, a 90% reduction in FLC-diff following SCT best predicted being alive at 3 or 5 years. The median OS among those with a 90% decrease was not reached compared to 37.4 months for the rest P < 0.001. The current study supports the notion that FLC response is a more useful measure of hematological response than M-protein response. It also highlights the importance of achieving at least a 90% reduction in the FLC-diff to improve the outcome of patients with light-chain AL.     

Fifteen year overall survival rates after autologous stem cell transplantation for AL amyloidosis

In appropriately selected patients with AL amyloidosis, autologous stem cell transplant (ASCT) is an established treatment modality with excellent outcomes and decreasing transplant related mortality (TRM) over time. We report on 15-year overall survival (OS) in 159 patients undergoing ASCT from 1996 to 2003, with median follow up of 17.1 years. Day 100 TRM was 13.2% (n = 21). The OS of ≥15 years was observed in 30% (47/159) of patients. Patients surviving ≥15 years were younger (53 vs 56 years, P = .02), less likely to have lambda as the involved light chain (62% vs 78%, P = .03) and were less likely to have heart involvement (32% vs 56%, P = .005). Median OS of patients with heart involvement vs not was 4.0 vs 11.1 years, P = .006 and actuarial 15-year OS was 23% vs 43%, respectively. A higher proportion of patients with OS ≥15 years received full-dose melphalan conditioning (81% vs 61%, P = .01), and achieved day 100 complete response (CR) (64% vs 24%, P < .001). Median OS amongst patients who achieved CR vs not was 19.3 vs 5.4 years, P < .001. Heart involvement, receiving full-dose melphalan and achieving CR remained independent predictors of OS. AL amyloidosis and related complications were the cause of death in 52% of patients overall (1-5 years post-transplant: 81%; 5-10 years: 62% and 10-15 years: 55%). These results reinforce the key role of ASCT in AL amyloidosis. With improvements in TRM and more options for relapsed disease, we expect the long-term survival post-transplant to improve significantly in the future.     

Peripheral blood biomarkers of early immune reconstitution in newly diagnosed multiple myeloma

Peripheral blood biomarkers of tumor microenvironment and immune surveillance are independent prognostic factors in multiple myeloma. The timing and prognostic impact of immune reconstitution has been studied after autologous hematopoietic stem cell transplantation, less is known about its significance in newly diagnosed multiple myeloma. We studied absolute lymphocyte (ALC) and absolute monocyte (AMC) counts at the time of treatment initiation and 1 month thereafter in 771 newly diagnosed patients. Two hundred and thirty-four patients (31%) had evidence of immune dysregulation at baseline (abnormal biomarkers). Eighty-seven of these patients (37%) recovered normal biomarkers at 1 month (early immune reconstitution). The absence of immune dysregulation at baseline (compared to the presence thereof) was associated with better overall survival (HR 0.77, 95% CI 0.61-0.97, P = 0.025, n = 771). The absence of immune dysregulation at 1 month (compared to the persistence or development thereof) was associated with better overall survival (HR 0.63, 95% CI 0.50-0.80, P < 0.001, n = 771). Early immune reconstitution (compared to the persistence or development of immune dysregulation) was associated with better overall survival (HR 0.62, 95% CI 0.43-0.92, P = 0.016, n = 771). Cytogenetic high-risk disease was negatively, and treatment with immunomodulators positively, associated with early immune reconstitution. The presence or development of immune dysregulation in newly diagnosed multiple myeloma is an independent risk factor. The favorable impact of early immune reconstitution suggests immune dysregulation to be a potentially modifiable risk factor that may be exploited for therapeutic benefit.     

Clinical features,laboratory characteristics and outcomes of patients with renal versus cardiac light chain amyloidosis

This study evaluated the differences in clinical features of 1077 newly diagnosed AL amyloidosis patients with renal involvement (n = 229, 21%), both cardiac and renal involvement (n = 443, 41%) and cardiac involvement (n = 405, 38%). Significant differences in dFLC (difference in involved and uninvolved light chains) were noted (renal, both, cardiac median: 83, 234 and 349 mg/l, P < 0.001). The proportion of patients with ≥ 10% bone marrow plasma cells (BMPCs) was lowest in renal only patients: 44%, 57%, 64%, respectively, P < 0.001. In a multivariate linear regression model incorporating organ involvement type and BMPCs ≥10%, organ involvement was a significant predictor of dFLC (P < 0.001). Median overall survival (OS) across the three groups was 83 vs. 19 vs. 16 months (P < 0.001) in patients not undergoing transplant and 5-year OS in patients undergoing transplant was 90% vs. 75% vs. 64% (P = 0.007), respectively. In conclusion, renal involvement alone or renal + cardiac involvement in AL amyloidosis is associated with lower circulating light chain burden, which cannot be fully explained by BMPC burden alone. Increased sensitivity of the kidney to light chains, given significant interactions with the renal tubular system and secretion of modified light chain products may play a role in pathogenesis of renal AL amyloidosis and warrants further investigation.     

Tuberculosis control in India: Refocus on nutrition

Many western societies have eliminated tuberculosis years before the advent of potent anti-tuberculous drugs, as a result of the improved standards of living and good nutrition. But even with the availability of powerful anti-tuberculous drugs, India still has a long road ahead to reach the “End TB by 2025” goal. One of the major reason is that tuberculosis control program in India till now have focused primarily on case detection and medical treatment of active tuberculosis. Drug treatment alone does not completely prevent the occurrence of new infections in the community and also contributes to development of drug resistant strains if used improperly or incompletely. Although the treatment of active cases can reduce the period of transmission of disease, a significant amount of transmission to contacts occurs even before they have been diagnosed and treated. Additionally, this approach cannot prevent re-activation to active TB in the vast pool of persons with latent TB infection. Tuberculosis occurs in those with suppressed cell mediated immunity mainly due to poor nutritional status. Improving the nutritional status of the society by several social interventions hand-in-hand with utilizing the available anti-tuberculous drugs is possibly the only effective strategy. Promising programmatic guidance for nutritional support in TB patients have been formulated by the Central TB division of India but it needs a refocusing of TB control strategies towards nutrition at all levels and strong public health actions for effective implementation.     

Outcomes and treatments of patients with immunoglobulin light chain amyloidosis who progress or relapse postautologous stem cell transplant

Immunoglobulin light chain (AL) Amyloidosis is a condition whereby misfolded proteins generated by plasma cells deposit in tissues causing organ dysfunction. Chemotherapy and autologous stem cell transplant when eligible are standard treatment options. Several studies report long‐term outcomes of patients post‐transplant. However, there is a paucity of literature describing outcomes of relapsed patients post‐transplant. We performed a retrospective study to assess outcomes and therapies employed upon relapse after transplant. Between 1996 and 2009, 410 patients received transplant at the Mayo Clinic as first‐line therapy. Of those patients, 42 (10%) died within 3 months of transplant, 64 (16%) died without documented relapse, 158 (38%) were alive without documented progression, and 146 (36%) had documented progression. Those 146 patients are the subject of our study, and their median time to hematologic relapse/progression was 23.6 months (95%CI 18.3, 26.3 months). Their median overall survival and 5‐yrs overall survival from post‐transplant relapse/progression was 51.7 months (95%CI 34.1–62.3) and 39%, respectively. The most common first regimen for treatment after relapse was lenalidomide or thalidomide. In conclusion, our study indicates that patients with AL amyloidosis fare well post‐transplant relapse/progression. Additionally, it provides a yardstick to design clinical trials to determine best treatment options.     

A phase 2 study of lenalidomide,rituximab, cyclophosphamide,and dexamethasone (LR‐CD) for untreated low‐grade non‐Hodgkin lymphoma requiring therapy

Patients with indolent non‐Hodgkin lymphoma (NHL) have multiple treatment options yet there is no consensus as to the best initial therapy. Lenalidomide, an immunomodulatory agent, has single agent activity in relapsed lymphoma. This trial was conducted to assess feasibility, efficacy, and safety of adding lenalidomide to rituximab, cyclophosphamide, and dexamethasone (LR‐CD) in untreated indolent NHL patients requiring therapy. This was a single institution phase II trial. Treatment consisted of IV rituximab 375 mg/m² day 1; oral lenalidomide 20 mg days 1–21; cyclophosphamide 250 mg/m² days 1, 8, and 15; and dexamethasone 40 mg days 1, 8, 15, and 22 of a 28‐day cycle. Treatment continued 2 cycles beyond best response for a maximum of 12 cycles without rituximab maintenance. Thirty‐three patients were treated. Median age was 68 (43–83 years). 39% had stage IV disease. Histologic subtypes included 8 follicular lymphoma (FL), 7 marginal zone lymphoma (MZL) (1 splenic, 2 extranodal, and 4 nodal), 15 Waldenström's macroglobulinemia (WM), 1 lymphoplasmacytic lymphoma, 1 small lymphocytic lymphoma, and 1 low‐grade B‐cell lymphoma with plasmacytic differentiation (unable to be classified better as MZL or LPL). Hematologic toxicity was the most common adverse event. Median time of follow‐up was 23.4 months (range 1.8–50.9). The overall response rate was 87.9%, with 30.3% complete response. The median duration of response was 38.7 months. The median progression free survival was 39.7 months, while median overall survival (OS) has not yet been reached. Lenalidomide can be safely added to a simple regimen of rituximab, oral cyclophosphamide, and dexamethasone and is an effective combination as initial therapy for low‐grade B‐cell NHL.