Personalized immunoglobulin aptamers for detection of multiple myeloma minimal residual disease in serum

Recent advances in targeted drug delivery systems for multiple myeloma

Despite significant therapeutic advances, multiple myeloma (MM) remains a challenging, incurable, hematological malignancy. The efficacy of traditional chemotherapy and currently available anti-MM agents is in part limited by their adverse effects, which restrict their therapeutic potential. Nanotherapeutics is an emerging field of cancer therapy that can overcome the biological and chemical barriers of existing anticancer drugs. This review presents an overview of recent advancements in nanoparticle- and immunotherapy-based drug delivery systems for MM treatment. It further delves into the targeting strategies, mechanism of controlled drug release, and challenges associated with the development of drug delivery systems for the treatment of MM.

Microfluidic isolation of aptamers with affinity towards multiple myeloma monoclonal immunoglobulins

Multiple myeloma (MM) is a bone marrow cancer of resident plasma cells that affects 125,000 patients in the U.S. with about 30,000 new cases per year. Its signature is the clonal proliferation of a single plasma cell that secretes a patient specific monoclonal immunoglobulin (M-Ig). Targeting the M-Ig in patient serum could allow sensitive and noninvasive identification of minimal residual disease in multiple myeloma. Aptamers, which are single-stranded oligonucleotides with affinity and specificity to a target molecule, have recently been introduced as affinity reagents for recognition of MM M-Igs. Here we exploit microfluidic SELEX technology to enable rapid and efficient generation of aptamers against M-Ig proteins from MM patients. We first characterize the technology by isolating aptamers with affinity towards the monoclonal antibody rituximab as a model M-Ig and then apply the technology to isolating aptamers specifically targeting M-Igs obtained from serum samples of MM patients. We demonstrate that high-affinity DNA aptamers (KD < 50 nM) for M-Ig proteins from a patient sample could be isolated via microfluidic SELEX within approximately 12 h and using less than 100 micrograms of patient M-Ig. Such aptamers can potentially be used in personalized monitoring of minimal residual disease in MM patients.

Race for the Cure: From the Oldest to the Newest Monoclonal Antibodies for Multiple Myeloma Treatment

Multiple myeloma is characterized by a wide clinical heterogeneity due to an intricate network of interactions between bone marrow-resident clonal plasma cells and the microenvironment. Over the last years, dramatic improvement in the understanding of these pathways led to the introduction of novel drugs with immune-mediated mechanisms of action. Some of these compounds, such as the anti-cd38 daratumumab and isatuximab, the anti-slamf-7 elotuzumab, and the antibody-drug conjugate belantamab-mafodotin, have been tested in large clinical trials and have now fully entered the real-life management. The bispecific T-cell engagers are under investigation with promising results, and other satisfactory data is expected from the application of nanotechnologies. The perfect timing to introduce these drugs in the sequence of treatment and their adverse events represent new challenges to be addressed, and further experience is required to improve their use.

Minimal Residual Disease Assessment in Multiple Myeloma Patients: Minimal Disease With Maximal Implications

Multiple Myeloma (MM), the second most common hematologic malignancy, has been the target of many therapeutic advances over the past two decades. The introduction of novel agents, such as proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, along with autologous hematopoietic stem cell transplantation (ASCT) in the current standard of care, has increased the median survival of myeloma patients significantly. Nevertheless, a curative treatment option continues to elude us, and MM remains an incurable disease, with patients relapsing even after achieving deep conventionally defined responses, underscoring the need for the development of sensitive methods that will allow for proper identification and management of the patients with a higher probability of relapse. Accurate detection of Minimal Residual Disease (MRD) from a bone marrow biopsy represents a relatively new approach of evaluating response to treatment with data showing clear benefit from obtaining MRD(-) status at any point of the disease course. As life expectancy for patients with MM continues to increase and deep responses are starting to become the norm, establishing and refining the role of MRD in the disease course is more relevant than ever. This review examines the different methods used to detect MRD and discusses future considerations regarding the implementation in day-to-day clinical practice and as a prospective primary endpoint for clinical trials.

Recent Advances in Micro/Nanomaterial-Based Aptamer Selection Strategies

Aptamers are artificial nucleic acid ligands that have been employed in various fundamental studies and applications, such as biological analyses, disease diagnostics, targeted therapeutics, and environmental pollutant detection. This review focuses on the recent advances in aptamer discovery strategies that have been used to detect various chemicals and biomolecules. Recent examples of the strategies discussed here are based on the classification of these micro/nanomaterial-mediated systematic evolution of ligands by exponential enrichment (SELEX) platforms into three categories: bead-mediated, carbon-based nanomaterial-mediated, and other nanoparticle-mediated strategies. In addition to describing the advantages and limitations of the aforementioned strategies, this review discusses potential strategies to develop high-performance aptamers.

Aptamers: Cutting edge of cancer therapies

The development of an aptamer-based therapeutic has rapidly progressed following the first two reports in the 1990s, underscoring the advantages of aptamer drugs associated with their unique binding properties. In 2004, the US Food and Drug Administration (FDA) approved the first therapeutic aptamer for the treatment of neovascular age-related macular degeneration, Macugen developed by NeXstar. Since then, eleven aptamers have successfully entered clinical trials for various therapeutic indications. Despite some of the pre-clinical and clinical successes of aptamers as therapeutics, no aptamer has been approved by the FDA for the treatment of cancer. This review highlights the most recent and cutting-edge approaches in the development of aptamers for the treatment of cancer types most refractory to conventional therapies. Herein, we will review (1) the development of aptamers to enhance anti-cancer immunity and as delivery tools for inducing the expression of immunogenic neoantigens; (2) the development of the most promising therapeutic aptamers designed to target the hard-to-treat cancers such as brain tumors; and (3) the development of "carrier" aptamers able to target and penetrate tumors and metastasis, delivering RNA therapeutics to the cytosol and nucleus.

Overcoming Drug Interference in Transfusion Testing: A Spotlight on Daratumumab

Daratumumab, a monoclonal antibody therapeutic, is highly efficacious and widely used in all stages of multiple myeloma and amyloidosis and has promising activity in other hematologic disorders. Daratumumab interacts with red blood cells, interfering with pre-transfusion testing. This interference can lead to compromising transfusion safety, extensive blood bank work ups and delays in provision of compatible units. Several methods have been developed to negate daratumumab interference with indirect antiglobulin testing. They are based on i) standard blood bank techniques including dithiothreitol and enzymatic treatment of reagent cells, using reagent red blood cells negative for CD38, ii) blocking CD38 antigens on reagent or donor cells, iii) neutralization of anti-CD38 antibody in patient plasma prior to testing, and iv) extended antigen typing of patient red blood cells in conjunction with provision of phenotypically matched units for transfusion. Implementation of those methods by the blood bank should be a planned effort coordinated with the patient’s clinical team. Timely involvement of blood bank and transfusion services and educational efforts by both blood banks and clinical providers can improve the overall daratumumab safety profile in regard to blood transfusion.