Heavy+light chain monitoring correlates with clinical outcome in multiple myeloma patients

Laboratory and Clinical Settings of Heavy/Light Chain (HLC) Assays in the Management of Monoclonal Gammopathies and Multiple Myeloma

The antibody-related immune response is mediated by immunoglobulins (Igs), soluble circulating glycoproteins produced by activated B cells that, upon the recognition of specific epitopes on pathogen surfaces, activate, proliferate, and differentiate into antibody-secreting plasma cells. Although the antibodies are effectors of the humoral immune adaptive response, their overproduction in response to a dysregulated proliferation of clonal plasma cell production in tumoral conditions (i.e., multiple myeloma), enriches the serum and urinary matrices, assuming the crucial role of biomarkers. Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the expansion and accumulation of clonally activated plasma cells in bone marrow, determining the release of high amounts of monoclonal component (MC) that can be detected as intact immunoglobulin (Ig), immunoglobulin fragments, or free light chains (FLCs). The importance of detecting biomarkers for the diagnosis, monitoring, and prognosis of diseases is highlighted by the international guidelines that recommend specific assays for the analysis of intact Igs and FLC. Moreover, a developed assay called Hevylite^® allows for the quantification of immunoglobulins that are both involved (iHLC) and not involved (uHLC) in the tumor process; this is a fundamental aspect of following up the patient's workup and evaluating the progression of disease, together with the treatments response. We here summarize the major points of the complex scenario involving monoclonal gammopathies and MM clinical management in view of advantages derived for the use of Hevylite^®.

The Current Role of the Heavy/Light Chain Assay in the Diagnosis, Prognosis and Monitoring of Multiple Myeloma: An Evidence-Based Approach

Despite tremendous progress being made in recent years, multiple myeloma (MM) remains a challenging disease. The laboratory plays a critical role in the overall management of patients. The diagnosis, prognosis, clinical monitoring and evaluation of the response are key moments in the clinical care process. Conventional laboratory methods have been and continue to be the basis of laboratory testing in monoclonal gammopathies, along with the serum free light chain test. However, more accurate methods are needed to achieve new and more stringent clinical goals. The heavy/light chain assay is a relatively new test which can overcome some of the limitations of the conventional methods for the evaluation of intact immunoglobulin MM patients. Here, we report an update of the evidence accumulated in recent years on this method regarding its use in MM.

HLC Pair Suppression as a Risk Factor for Bacterial Bloodstream Infections and Early Mortality in Newly Diagnosed Intact Immunoglobulin Multiple Myeloma Patients

Despite the outstanding progresses in Multiple Myeloma treatment options in the last decades, it remains an incurable disease nowadays. Infectious events are a complication due to an impaired immune system associated with MM, sometimes a life-threatening one, particularly on the first months after the diagnosis. Both the underlying disease and treatment can contribute to the infection risk, so a biomarker that assess this risk could be highly relevant for a more tailored management of the patient. The measurement of the heavy+light chain (HLC) pairs of immunoglobulins in serum allows the quantification of both the monoclonal component and the non-monoclonal immunoglobulin of the same isotype. This approach has demonstrated high sensitivity for the detection of the clonality and prognostic value for MM. HLC pair suppression itself has prognostic power and it has been proposed to be a reflection of the immune system' attempt to control the tumor. In this study we evaluated the impact of the HLC pair suppression on the rate of bloodstream infections (BSI) and early death in 115 newly diagnosed MM patients. Twenty-one percent of the patients suffered a BSI in the first 6 months after diagnosis, of which 58% died within this period, accounting to 67% of the early deaths in global and highlighting the major impact of infections on MM patients in a "real world" setting. Severe HLC pair suppression identified patients with a higher risk of early BSI (HR: 6,97, p=0,009), and extreme HLC pair suppression together with BSI event and age >65 were independent risk factors for early death (p<0,001). Based on these factors, a stratification model was generated to allow identify patients at a higher risk of early death and poorer OS, with an apparently better performance than the ISS on the early death context. In conclusion, HLC pair suppression associates with both a higher risk of life-threatening early infection and early death in newly diagnosed MM patients. Patients older than 65 with extreme HLC pair suppression and BSI are at a high risk of early death, and thus patients presenting with these criteria have a very adverse prognosis.

Serum Hevylite® assay in the differential diagnosis of patients with high suspicion of AL Amyloidosis

INTRODUCTION

AL amyloidosis (AL) is a malignant form of plasma cell dyscrasia (PCD). It is insidious, and its end-organ damage can mimic that of common diseases. At diagnosis, routine tests for monoclonal protein are insufficient for the differential diagnosis. We hypothesized that Hevylite^® (HLC) isotype patterns may help discriminate between AL and benign PCD states.

METHODS

Serum samples of patients with a high clinical suspicion of AL were prospectively tested for IgGκ, IgGλ, IgAκ, IgAλ, IgMκ, and IgMλ concentrations and ratios using Hevylite^® assays in a blinded manner. The results were correlated with the final diagnosis.

RESULTS

Of the 99 samples analyzed, 46 were newly diagnosed AL, and the majority, 38 (82.6%), presented with suppression of at least one HLC isotype. Of the 53 benign PCD patients, 36 (67.9%) presented with elevation of at least one HLC isotype. By multivariate analysis, Hevylite^® was the best independent test predictor of AL amyloidosis. HLC suppression had an odds ratio (OR) of 14.591, and elevation an OR of 10.149, and thus were significant variables in the diagnosis and exclusion of AL. Furthermore, patients with both HLC suppression, together with no elevation, had an OR of 316.69 to be diagnosed with AL rather than a benign PCD.

CONCLUSIONS

Hevylite^® HLC analysis for Ig isotypes patterns offers an effective non-invasive tool in the evaluation of patients with high suspicion of AL and may assist further explorative decisions for diagnosis.

Early M-Protein Dynamics Predicts Progression-Free Survival in Patients With Relapsed/Refractory Multiple Myeloma

This study aimed to predict long‐term progression‐free survival (PFS) using early M‐protein dynamic measurements in patients with relapsed/refractory multiple myeloma (MM). The PFS was modeled based on dynamic M‐protein data from two phase III studies, POLLUX and CASTOR, which included 569 and 498 patients with relapsed/refractory MM, respectively. Both studies compared active controls (lenalidomide and dexamethasone, and bortezomib and dexamethasone, respectively) alone vs. in combination with daratumumab. Three M‐protein dynamic features from the longitudinal M‐protein data were evaluated up to different time cutoffs (1, 2, 3, and 6 months). The abilities of early M‐protein dynamic measurements to predict the PFS were evaluated using Cox proportional hazards survival models. Both univariate and multivariable analyses suggest that maximum reduction of M‐protein (i.e., depth of response) was the most predictive of PFS. Despite the statistical significance, the baseline covariates provided very limited predictive value regarding the treatment effect of daratumumab. However, M‐protein dynamic features obtained within the first 2 months reasonably predicted PFS and the associated treatment effect of daratumumab. Specifically, the areas under the time‐varying receiver operating characteristic curves for the model with the first 2 months of M‐protein dynamic data were ~ 0.8 and 0.85 for POLLUX and CASTOR, respectively. Early M‐protein data within the first 2 months can provide a prospective and reasonable prediction of future long‐term clinical benefit for patients with MM.

Polyclonal Immunoglobulin Recovery after Autologous Stem Cell Transplantation Is an Independent Prognostic Factor for Survival Outcome in Patients with Multiple Myeloma

We retrospectively analyzed multiple myeloma (MM) patients who underwent autologous stem cell transplantation (ASCT) without maintenance therapy to assess the impact of recovery of normal immunoglobulin (Ig) on clinical outcomes. The recovery of polyclonal Ig was defined as normalization of all values of serum IgG, IgA, and IgM 1 year after ASCT. Among 50 patients, 26 patients showed polyclonal Ig recovery; 14 patients were in ≥complete response (CR) and 12 remained in non-CR after ASCT. The patients with Ig recovery exhibited a significantly better progression-free survival (PFS, median, 46.8 vs. 26.7 months, p = 0.0071) and overall survival (OS, median, not reached vs. 65.3 months, p < 0.00001) compared with those without Ig recovery. The survival benefits of Ig recovery were similarly observed in ≥CR patients (median OS, not reached vs. 80.5 months, p = 0.061) and non-CR patients (median OS, not reached vs. 53.2 months, p = 0.00016). Multivariate analysis revealed that non-CR and not all Ig recovery were independent prognostic factors for PFS (HR, 4.284, 95%CI (1.868–9.826), p = 0.00059; and HR, 2.804, 95%CI (1.334–5.896), p = 0.0065, respectively) and also for OS (HR, 8.245, 95%CI (1.528–44.47), p = 0.014; and HR, 36.55, 95%CI (3.942–338.8), p = 0.0015, respectively). Therefore, in addition to the depth of response, the recovery of polyclonal Ig after ASCT is a useful indicator especially for long-term outcome and might be considered to prevent overtreatment with maintenance therapy in transplanted patients with MM.

A new risk model to predict time to first treatment in chronic lymphocytic leukemia based on heavy chain immunoparesis and summated free light chain

BACKGROUND

Chronic lymphocytic leukemia (CLL) is frequently accompanied by immune dysregulation.

AIMS

In this multicenter prospective study, we investigated whether heavy + light chains (HLC: IgGκ, IgGλ, IgAκ, IgAκ, IgMκ, IgMλ) and IgG subclasses (IgG1, IgG2, IgG3, and IgG4) could be used as novel prognostic markers of immunoparesis in 105 treatment-naïve patients with CLL.

RESULTS

Heavy + light chains immunoparesis of ≥1, ≥2, and ≥3 isotypes was evident in 74 (70%), 58 (55%), and 36 (34%) patients, respectively. Severe HLC immunoparesis was identified in 40 (38%) patients. Of the IgG subclasses, IgG1 and IgG2 were most frequently suppressed, affecting 46 (44%) and 36 (34%) patients, respectively; 63 (60%) patients had low levels of at least one IgG subclass. In multivariate analysis, severe HLC immunoparesis (hazard ratio [HR]: 36.5; P = .010) and ΣFLC ≥ 70 mg/L (HR: 13.2; P = .004) were the only factors independently associated with time to first treatment (TTFT). A risk model including these variables identified patients with 0, 1, and 2 risk factors and significantly different TTFT (P < .001). Patients with two factors represented an ultra-high-risk group with a median TTFT of only 1.3 months.

CONCLUSION

The above findings demonstrate the potential for the use of HLC immunoparesis, together with sFLC measurements, as future prognostic biomarkers in CLL.

Redirected optimized cell killing (ROCK®): A highly versatile multispecific fit-for-purpose antibody platform for engaging innate immunity

Redirection of immune cells to efficiently eliminate tumor cells holds great promise. Natural killer cells (NK), macrophages, or T cells are specifically engaged with target cells expressing markers after infection or neoplastic transformation, resulting in their activation and subsequent killing of those targets. Multiple strategies to redirect immunity have been developed in the past two decades, but they have technical hurdles or cause undesirable side-effects, as exemplified by the T cell-based chimeric antigen receptor approaches (CAR-T therapies) or bispecific T cell engager platforms. Our first-in-class bispecific antibody redirecting innate immune cells to tumors (AFM13, a CD30/CD16A-specific innate immune cell engager) has shown signs of clinical efficacy in CD30-positive lymphomas and the potential to be safely administered, indicating a wider therapeutic window compared to T cell engaging therapies. AFM13 is the most advanced candidate from our fit-for-purpose redirected optimized cell killing (ROCK®) antibody platform, which comprises a plethora of CD16A-binding innate immune cell engagers with unique properties. Here, we discuss aspects of this modular platform, including the advantages of innate immune cell engagement over classical monoclonal antibodies and other engager concepts. We also present details on its potential to engineer a fit-for-purpose innate immune cell engager format that can be equipped with unique CD16A domains, modules that influence pharmacokinetic properties and molecular architectures that influence the activation of immune effectors, as well as tumor targeting. The ROCK® platform is aimed at the activation of innate immunity for the effective lysis of tumor cells and holds the promise of overcoming limitations of other approaches that redirect immune cells by widening the therapeutic window.

Prognostic utility of serum free light chain ratios and heavy-light chain ratios in multiple myeloma in three PETHEMA/GEM phase III clinical trials

We investigated the prognostic impact and clinical utility of serum free light chains (sFLC) and serum heavy-light chains (sHLC) in patients with multiple myeloma treated according to the GEM2005MENOS65, GEM2005MAS65, and GEM2010MAS65 PETHEMA/GEM phase III clinical trials. Serum samples collected at diagnosis were retrospectively analyzed for sFLC (n = 623) and sHLC (n = 183). After induction or autologous transplantation, 309 and 89 samples respectively were available for sFLC and sHLC assays. At diagnosis, a highly abnormal (HA) sFLC ratio (sFLCr) (<0.03 or >32) was not associated with higher risk of progression. After therapy, persistence of involved-sFLC levels >100 mg/L implied worse survival (overall survival [OS], P = 0.03; progression-free survival [PFS], P = 0.007). Among patients that achieved a complete response, sFLCr normalization did not necessarily indicate a higher quality response. We conducted sHLC investigations for IgG and IgA MM. Absolute sHLC values were correlated with monoclonal protein levels measured with serum protein electrophoresis. At diagnosis, HA-sHLCrs (<0.29 or >73) showed a higher risk of progression (P = 0.006). Additionally, involved-sHLC levels >5 g/L after treatment were associated with shorter survival (OS, P = 0.001; PFS, P = 0.018). The HA-sHLCr could have prognostic value at diagnosis; absolute values of involved-sFLC >100 mg/L and involved-sHLC >5 g/L could have prognostic value after treatment.

The clinical utility of serum free light chain and heavy/light chain assays in monitoring disease activity in patients with IgG myeloma after achieving a deep response

Heavy/light chain (HLC) assay will enable us to evaluate the changes in the concentrations of iHLC and uHLC separately and to better identify whether the change observed is clonal or reactive. It would therefore aid in decision making for earlier implementation or discontinuation of treatment for patients with intact immunoglobulin multiple myeloma (MM).

Recombinant Antibodies to Arm Cytotoxic Lymphocytes in Cancer Immunotherapy

Immunotherapy has the potential to support and expand the body's own armamentarium of immune effector functions, which have been circumvented during malignant transformation and establishment of cancer and is presently considered to be the most promising treatment option for cancer patients. Recombinant antibody technologies have led to a multitude of novel antibody formats, which are in clinical development and hold great promise for future therapies. Among these formats, bispecific antibodies are extremely versatile due to their high efficacy to recruit and activate anti-tumoral immune effector cells, their excellent safety profile, and the opportunity for use in combination with cellular therapies. This review article summarizes the latest developments in cancer immunotherapy using immuno-engagers for recruiting T cells and NK cells to the tumor site. In addition to antibody formats, malignant cell targets, and immune cell targets, opportunities for combination therapies, including check point inhibitors, cytokines and adoptive transfer of immune cells, will be summarized and discussed.