Mechanisms of lenalidomide sensitivity and resistance

Forcing Ahead: Second-Line Treatment Options for Lenalidomide-Refractory Multiple Myeloma

The therapeutic landscape for multiple myeloma has gradually expanded in recent decades, leading to unprecedented deep and sustained responses as well as remarkable improvements in patient survival. Nonetheless, changes in treatment algorithms have raised new demands for patients with relapsed/refractory disease, as prior exposure and refractoriness to prior therapies impact the choice of subsequent treatments. In particular, refractoriness to lenalidomide-an established backbone of treatment in both front-line and maintenance settings and a key component of many approved regimens used in relapsed disease-is associated with suboptimal clinical outcomes. Therefore, identifying the most appropriate management in lenalidomide-refractory patients, and even more so in patients who are refractory to more than one agent, is critical. At present, treatment options for this growing subgroup of patients are still limited; however, recent data from clinical research are promising. Herein, we summarized the currently available treatment options and discuss future directions based on the latest results from ongoing clinical trials.

Dual targeting PD-L1 and 4-1BB to overcome dendritic cell-mediated lenalidomide resistance in follicular lymphoma

Immunomodulatory agent lenalidomide is effective in treating follicular lymphoma (FL). We conducted the first trial of immunotherapy rituximab plus lenalidomide in newly diagnosed FL in China (NCT03715309). One-hundred and fifteen patients were enrolled and treated with rituximab 375 mg/m2 intravenously on day 0 and lenalidomide 25 mg orally on day 1-10 for 6 cycles of induction treatment, as well as lenalidomide for 6 cycles and rituximab for 8 cycles of maintenance treatment. We found that inferior progression-free survival of the patients was significantly associated with elevated serum β2m and lymph node >6 cm, linking to decreased lymphoma cell autophagy and dendritic cell infiltration within the tumor microenvironment. PU.1 transcriptionally downregulated PD-L1 (Programmed death ligand 1) expression and upregulated 4-1BBL (4-1BB ligand) expression, increased lymphoma cell autophagy and dendritic cell maturation via PD-1/PD-L1 and 4-1BB/4-1BBL interaction. In vitro in co-culture system and in vivo in murine xenograft model, knockdown of PU.1 induced lenalidomide resistance, but sensitized FL cells to bi-specific PD-L1/4-1BB antibody or combined treatment of PD-L1 inhibitor and 4-1BB agonist. Collectively, PU.1 is essential in immunomodulatory effect of FL through PD-1/PD-L1- and 4-1BB/4-1BBL-mediated microenvironmental modulation. Dual targeting PD-L1 and 4-1BB could be an alternative immunotherapeutic strategy in the chemo-free era of FL treatment.

Intercalation of the anticancer drug lenalidomide into montmorillonite for bioavailability improvement: a computational study

CONTEXT

Lenalidomide (LEN) is used for the treatment of myeloma blood cancer disease. It has become one of the most efficient drugs to halt this disease. LEN is a low-soluble drug in aqueous media. The search of a pharmaceutical preparation to improve the bioavailability and, therefore, to optimize its efficiency is an important issue for pharmaceutical industries and health care. The use of natural excipients such as montmorillonite (MNT) can provide changes in the physical-chemical properties for improving the bioavailability of this drug. We present the first computational study at the atomic scale of the periodic crystal forms of the polymorphs for this anticancer drug, highly demanded in the pharmacy market. In addition, we propose a pharmaceutical preparation by intercalation of LEN in natural MNT. So, our calculations predict that LEN can be intercalated in the interlayer space of MNT, and be released in aqueous media, and physiological aqueous media in consequence. This release process is a more exothermic reaction than the unpacking energy of any of its polymorphs. Besides, the infrared spectra of the LEN molecule and its crystal polymorphs, and LEN intercalated in the confined space of MNT, have been calculated at different levels of theory. The band frequencies have been assigned, matching with the experimental bands, predicting the use of this technique for experimental studies.

METHOD

In this work, the method is aimed to explore this research at the atomic and molecular level by using computational modelling methods including INTERFACE FF and other FF along with quantum mechanical calculations (Dmol3 and CASTEP) of 3-D periodical systems applying periodical boundary conditions. Models of the isolated molecule and two polymorphs of the crystal structures, with the model of bulk water and LEN intercalated in the MNT model, have been considered. An analysis of the intermolecular interactions is accomplished.

Proceedings from the First Onco Summit: LATAM Chapter, 19-20 May 2023, Rio de Janeiro, Brazil

The Onco Summit 2023: The Latin American (LATAM) Chapter took place over two days, from 19-20 May 2023, in Brazil. The event aimed to share the latest updates across various oncology disciplines, address critical clinical challenges, and exchange best practices to ensure optimal patient treatment. More than 30 international and regional speakers and more than 300 oncology specialists participated in the Summit. The Summit discussions centered on common challenges and therapeutic advances in cancer care, with a specific focus on the unique obstacles faced in LATAM and examples of adaptable strategies to address these challenges. The Summit also facilitated the establishment of a network of oncologists, hematologists, and scientists in LATAM, enabling collaboration to improve cancer care, both in this region and globally, through drug development and clinical research. This report summarizes the key discussions from the Summit for the global and LATAM oncology community.

Targeted protein degradation: from mechanisms to clinic

Targeted protein degradation refers to the use of small molecules to induce the selective degradation of proteins. In its most common form, this degradation is achieved through ligand-mediated neo-interactions between ubiquitin E3 ligases - the principal waste disposal machines of a cell - and the protein targets of interest, resulting in ubiquitylation and subsequent proteasomal degradation. Notable advances have been made in biological and mechanistic understanding of serendipitously discovered degraders. This improved understanding and novel chemistry has not only provided clinical proof of concept for targeted protein degradation but has also led to rapid growth of the field, with dozens of investigational drugs in active clinical trials. Two distinct classes of protein degradation therapeutics are being widely explored: bifunctional PROTACs and molecular glue degraders, both of which have their unique advantages and challenges. Here, we review the current landscape of targeted protein degradation approaches and how they have parallels in biological processes. We also outline the ongoing clinical exploration of novel degraders and provide some perspectives on the directions the field might take.

Single-cell transcriptional profile of CD34+ hematopoietic progenitor cells from del(5q) myelodysplastic syndromes and impact of lenalidomide

While myelodysplastic syndromes with del(5q) (del(5q) MDS) comprises a well-defined hematological subgroup, the molecular basis underlying its origin remains unknown. Using single cell RNA-seq (scRNA-seq) on CD34+ progenitors from del(5q) MDS patients, we have identified cells harboring the deletion, characterizing the transcriptional impact of this genetic insult on disease pathogenesis and treatment response. Interestingly, both del(5q) and non-del(5q) cells present similar transcriptional lesions, indicating that all cells, and not only those harboring the deletion, may contribute to aberrant hematopoietic differentiation. However, gene regulatory network (GRN) analyses reveal a group of regulons showing aberrant activity that could trigger altered hematopoiesis exclusively in del(5q) cells, pointing to a more prominent role of these cells in disease phenotype. In del(5q) MDS patients achieving hematological response upon lenalidomide treatment, the drug reverts several transcriptional alterations in both del(5q) and non-del(5q) cells, but other lesions remain, which may be responsible for potential future relapses. Moreover, lack of hematological response is associated with the inability of lenalidomide to reverse transcriptional alterations. Collectively, this study reveals transcriptional alterations that could contribute to the pathogenesis and treatment response of del(5q) MDS.

A Phase I Trial Evaluating the Addition of Lenalidomide to Patients with Relapsed/Refractory Multiple Myeloma Progressing on Ruxolitinib and Methylprednisolone

BACKGROUND

Ruxolitinib (RUX), an orally administered selective Janus kinase 1/2 inhibitor, has received approval for the treatment of myelofibrosis, polycythemia vera, and graft-versus-host disease. We have previously demonstrated the anti-multiple myeloma effects of RUX alone and in combination with the immunomodulatory agent lenalidomide (LEN) and glucocorticosteroids both pre-clinically and clinically.

OBJECTIVE

This study aims to evaluate whether LEN can achieve clinical activity among patients with multiple myeloma progressing on the combination of RUX and methylprednisolone (MP).

METHODS

In this part of a phase I, multicenter, open-label study, we evaluated the safety and efficacy of RUX and MP for patients with multiple myeloma with progressive disease who had previously received a proteasome inhibitor, LEN, glucocorticosteroids, and at least three prior regimens; we also determined the safety and efficacy of adding LEN at the time of disease progression from the initial doublet treatment. Initially, all subjects received oral RUX 15 mg twice daily and oral MP 40 mg every other day. Those patients who developed progressive disease according to the International Myeloma Working Group criteria then received LEN 10 mg once daily on days 1-21 within a 28-day cycle in addition to RUX and MP, which were administered at the same doses these patients were receiving at the time progressive disease developed.

RESULTS

Twenty-nine subjects (median age 64 years; 18 [62%] male) were enrolled in this part of the study and initially received the two-drug combination of RUX and MP. The median number of prior therapies was six (range 3-12). The overall response rate from this two-drug combination was 31% and the clinical benefit rate was 34%. The best responses were 1 very good partial response, 8 partial responses, 1 minor response, 12 stable disease, and 7 progressive disease. The median progression-free survival was 3.5 months (range  0.5-36.2 months). The median time to response was 3.0 months. The median duration of response was 12.5 months (range 2.8-36.2 months). Twenty (69%) patients who showed progressive disease had LEN added to RUX and MP; all patients had prior exposure to LEN and all but one patient was refractory to their last LEN-containing regimen. After the addition of LEN, the overall response rate was 30% and the clinical benefit rate was 40%. The best responses of patients following the addition of LEN were 2 very good partial responses, 4 partial responses, 2 minor responses, 8 stable disease, and 4 progressive disease. The median time to response was 2.6 months (range 0.7-15.0 months). The median duration of response was not reached. The median progression-free survival following the addition of LEN was 3.5 months (range 0.3-25.9 months).

CONCLUSIONS

For patients with multiple myeloma, treatment with RUX and MP is effective and well tolerated, and LEN can be used to extend the benefit of this RUX-based treatment.

CLINICAL TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov, NCT03110822, and is ongoing.

A randomised evaluation of low-dose cytosine arabinoside plus lenalidomide versus single-agent low-dose cytosine arabinoside in older patients with acute myeloid leukaemia: Results from the LI-1 trial

Improving outcomes for older patients with acute myeloid leukaemia remains an unmet need. As part of the LI-1 trial, we evaluated lenalidomide (LEN) in combination with low-dose cytosine arabinoside (LDAC) in patients aged >60 years unfit for intensive therapy and compared this to LDAC alone. Two hundred and two patients, randomised 1:1, were evaluable. Overall response rate (CR + CRi) was higher for LDAC + LEN versus LDAC (26% and 13.7% respectively p = 0.031). However, there was no difference in overall survival between the arms (14% and 11.5% at 2 years for LDAC + LEN and LDAC respectively). The addition of LEN was associated with increased toxicity and supportive care requirements.

Three-year progression-free survival of a patient with concomitant mucinous adenocarcinoma of the colon with peritoneal dissemination and multiple myeloma who received lenalidomide: a case report

BACKGROUND

Concomitant multiple myeloma (MM) and other primary malignancies is rare. Therefore, the treatment outcomes of patients with these conditions have not been well discussed. Lenalidomide is an oral thalidomide analog drug used for MM. Recently, the antitumor effect of lenalidomide has been gaining attention, and lenalidomide has been applied for managing solid tumors. The current case showed the treatment course of a patient treated with lenalidomide for concomitant MM and colon cancer with peritoneal dissemination.

CASE PRESENTATION

A 74-year-old female patient receiving treatment for MM was diagnosed with mucinous adenocarcinoma of the transverse colon. The patient was clinically diagnosed with stage IIIC T4aN2M0 disease. Subsequently, laparoscopic colectomy with lymph node dissection was planned. However, intraperitoneal observation revealed peritoneal dissemination that had sporadically and widely spread. Therefore, palliative partial colectomy was performed to prevent future hemorrhage or obstruction. The patient was discharged on the 10th postoperative day without postoperative complication. Based on the patient's preference, lenalidomide was continually administered for MM without systemic chemotherapy. The patient survived for > 36 months without any signs of tumor progression.

CONCLUSION

The current case first showed the treatment course of concomitant MM and colon cancer. The antitumor effect of lenalidomide can possibly contribute to 3-year progression-free survival in patients with mucinous adenocarcinoma of the colon with peritoneal dissemination.

First-Line Therapy for Nodal T-cell Non-Hodgkin Lymphomas: an Unmet Need in Hematology

PURPOSEOF REVIEW

The main aim of this review is to summarize first-line therapy of nodal T-cell non-Hodgkin lymphoma.

RECENT FINDINGS

Current treatment with CHOP chemotherapy results in poor outcomes in the majority of patients. However, there are advances within the field. First breakthrough is the ECHELON-2 trial which showed that the addition of brentuximab vedotin improves outcomes in anaplastic large cell lymphoma. However, other types of peripheral T-cell non-Hodgkin lymphoma were underrepresented with optimal treatment not known. Second breakthrough is an increase of autologous stem cell transplantation usage in the first complete metabolic remission, except in ALK + anaplastic large cell lymphoma, offering better disease control. Despite advances in the field, CHOP remains the standard treatment for the majority of these lymphomas, but multiple trials are underway with the aim to improve this unmet need in hematology and, hopefully, leading us to a new era in the treatment of peripheral T-cell lymphomas.

SETDB1 induces lenalidomide resistance in multiple myeloma cells via epithelial‑mesenchymal transition and PI3K/AKT pathway activation

SET domain bifurcated histone lysine methyltransferase 1 (SETDB1) is a histone H3K9 methyltransferase that stimulates cell proliferation by methylating AKT, which contributes to drug resistance in multiple myeloma (MM). Lenalidomide is an immunomodulatory agent widely used in the treatment of MM. However, lenalidomide resistance occurs in patients with MM. Currently, the role of SETDB1 in lenalidomide resistance in MM remains unclear. Thus, the present study aimed to explore the functional association between SETDB1 and lenalidomide resistance in MM. The analysis of GEO datasets revealed that SETDB1 was upregulated in lenalidomide-resistant MM cells and that its expression was associated with poor prognosis of patients with MM. Apoptosis analysis revealed that overexpression of SETDB1 in MM cells significantly decreased apoptosis, while knockdown of SETDB1 increased apoptosis. Furthermore, the IC₅₀ value of lenalidomide in MM cells increased following SETDB1 overexpression and decreased following SETDB1 silencing. Additionally, SETDB1 mediated epithelial-mesenchymal transition (EMT) and activated the PI3K/AKT pathway. Mechanistic analysis revealed that inhibition of PI3K/AKT signaling in MM cells increased apoptosis, sensitized the cells to lenalidomide and inhibited EMT, whereas SETDB1 overexpression inhibited the effects of PI3K/AKT cascade inhibition. In conclusion, the findings of the present study indicated that SETDB1 promoted lenalidomide resistance in MM cells by promoting EMT and the PI3K/AKT signaling pathway. Thus, SETDB1 may be a potential therapeutic target for MM.

Targeted protein degrader development for cancer: advances, challenges, and opportunities

Anticancer-targeted therapies inhibit various kinases implicated in cancer and have been used in clinical settings for decades. However, many cancer-related targets are proteins without catalytic activity and are difficult to target using traditional occupancy-driven inhibitors. Targeted protein degradation (TPD) is an emerging therapeutic modality that has expanded the druggable proteome for cancer treatment. With the entry of new-generation immunomodulatory drugs (IMiDs), selective estrogen receptor degraders (SERDs), and proteolysis-targeting chimera (PROTAC) drugs into clinical trials, the field of TPD has seen explosive growth in the past 10 years. Several challenges remain that need to be tackled to increase successful clinical translation of TPD drugs. We present an overview of the global landscape of clinical trials of TPD drugs over the past decade and summarize the clinical profiles of new-generation TPD drugs. In addition, we highlight the challenges and opportunities for the development of effective TPD drugs for future successful clinical translation.

Dual IKZF2 and CK1α degrader targets acute myeloid leukemia cells

Acute myeloid leukemia (AML) is a hematologic malignancy for which several epigenetic regulators have been identified as therapeutic targets. Here we report the development of cereblon-dependent degraders of IKZF2 and casein kinase 1α (CK1α), termed DEG-35 and DEG-77. We utilized a structure-guided approach to develop DEG-35 as a nanomolar degrader of IKZF2, a hematopoietic-specific transcription factor that contributes to myeloid leukemogenesis. DEG-35 possesses additional substrate specificity for the therapeutically relevant target CK1α, which was identified through unbiased proteomics and a PRISM screen assay. Degradation of IKZF2 and CK1α blocks cell growth and induces myeloid differentiation in AML cells through CK1α-p53- and IKZF2-dependent pathways. Target degradation by DEG-35 or a more soluble analog, DEG-77, delays leukemia progression in murine and human AML mouse models. Overall, we provide a strategy for multitargeted degradation of IKZF2 and CK1α to enhance efficacy against AML that may be expanded to additional targets and indications.

Discovery of Highly Potent CRBN Ligands and Insight into Their Binding Mode through Molecular Docking and Molecular Dynamics Simulations

Cereblon (CRBN) is a substrate receptor of E3 ubiquitin ligase as well as the target of thalidomide and lenalidomide, plays a vital role in endogenous protein degradation. In this article, two series of compounds with novel structure were designed, synthesized and evaluated against CRBN. YJ1b, designed based on our previous finding, shown strong binding affinity toward CRBN (IC₅₀ =0.206 μM) by forming a salt bridge interaction with amino acid residue Glu377 of CRBN, it was 13-fold compared with that of lenalidomide (IC₅₀ =2.694 μM) in TR-FRET assay. YJ2c and YJ2h, two analogs of YJ1b, also exhibit high binding affinity toward CRBN (IC₅₀ =0.211 μM and IC₅₀ =0.282 μM, respectively). While, molecular docking and 100 ns molecular dynamic simulation studies were conducted to insight into the unique binding mode of YJ1b, YJ2c and YJ2e toward CRBN. The new compounds with special binding mode in this article may serve for the further optimization and discovery of novel high potent CRBN ligands.

Relapsed/Refractory Multiple Myeloma: A Review of Available Therapies and Clinical Scenarios Encountered in Myeloma Relapse

Multiple myeloma remains an incurable disease with the usual disease course requiring induction therapy, autologous stem cell transplantation for eligible patients, and long-term maintenance. Risk stratification tools and cytogenetic alterations help inform individualized therapeutic choices for patients in hopes of achieving long-term remissions with preserved quality of life. Unfortunately, relapses occur at different stages of the course of the disease owing to the biological heterogeneity of the disease. Addressing relapse can be complex and challenging as there are both therapy- and patient-related factors to consider. In this broad scoping review of available therapies in relapsed/refractory multiple myeloma (RRMM), we cover the pharmacologic mechanisms underlying active therapies such as immunomodulatory agents (IMiDs), proteasome inhibitors (PIs), monoclonal antibodies (mAbs), traditional chemotherapy, and Venetoclax. We then review the clinical data supporting the use of these therapies, organized based on drug resistance/refractoriness, and the role of autologous stem cell transplant (ASCT). Approaches to special situations during relapse such as renal impairment and extramedullary disease are also covered. Lastly, we look towards the future by briefly reviewing the clinical data supporting the use of chimeric antigen receptor (CAR-T) therapy, bispecific T cell engagers (BITE), and Cereblon E3 Ligase Modulators (CELMoDs).

Targeting cereblon in hematologic malignancies

The protein cereblon (CRBN) is a substrate receptor of the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase complex CRL4^CRBN. Targeting CRBN mediates selective protein ubiquitination and subsequent degradation via the proteasome. This review describes novel thalidomide analogs, immunomodulatory drugs, also known as CRBN E3 ubiquitin ligase modulators or molecular glues (avadomide, iberdomide, CC-885, CC-90009, BTX-1188, CC-92480, CC-99282, CFT7455, and CC-91633), and CRBN-based proteolysis targeting chimeras (PROTACs) with increased efficacy and potent activity for application in hematologic malignancies. Both types of CRBN-binding drugs, molecular glues, and PROTACs stimulate the interaction between CRBN and its neosubstrates, recruiting target disease-promoting proteins and the E3 ubiquitin ligase CRL4^CRBN. Proteins that are traditionally difficult to target (transcription factors and oncoproteins) can be polyubiquitinated and degraded in this way. The competition of CRBN neosubstrates with endogenous CRBN-interacting proteins and the pharmacology and rational combination therapies of and mechanisms of resistance to CRL4^CRBN modulators or CRBN-based PROTACs are described.

PPAR agonists attenuate lenalidomide's anti-myeloma activity in vitro and in vivo

Many patients with multiple myeloma (MM) have comorbidities and are treated with PPAR agonists. Immunomodulatory agents (IMiDs) are the cornerstones for MM therapy. Currently, little is known about how co-administration of PPAR agonists impacts lenalidomide treatment in patients with MM. Here, we determined the effects of PPAR agonists on anti-myeloma activities of lenalidomide in vitro and in a myeloma xenograft mouse model. Genetic overexpression and CRISPR/cas9 knockout experiments were performed to determine the role of CRBN in the PPAR-mediated pathway. A retrospective cohort study was performed to determine the correlation of PPAR expression with the outcomes of patients with MM. PPAR agonists down-regulated CRBN expression and reduced the anti-myeloma efficacy of lenalidomide in vitro and in vivo. Co-treatment with PPAR antagonists increased CRBN expression and improved sensitivity to lenalidomide. PPAR expression was higher in bone marrow cells of patients with newly diagnosed MM than in normal control bone marrow samples. High PPAR expression was correlated with poor clinical outcomes. Our study provides the first evidence that PPARs transcriptionally regulate CRBN and that drug-drug interactions between PPAR agonists and IMiDs may impact myeloma treatment outcomes.

Kinase Inhibition in Multiple Myeloma: Current Scenario and Clinical Perspectives

Multiple myeloma (MM) is a blood cell neoplasm characterized by excessive production of malignant monoclonal plasma cells (activated B lymphocytes) by the bone marrow, which end up synthesizing antibodies or antibody fragments, called M proteins, in excess. The accumulation of this production, both cells themselves and of the immunoglobulins, causes a series of problems for the patient, of a systemic and local nature, such as blood hyperviscosity, renal failure, anemia, bone lesions, and infections due to compromised immunity. MM is the third most common hematological neoplasm, constituting 1% of all cancer cases, and is a disease that is difficult to treat, still being considered an incurable disease. The treatments currently available cannot cure the patient, but only extend their lifespan, and the main and most effective alternative is autologous hematopoietic stem cell transplantation, but not every patient is eligible, often due to age and pre-existing comorbidities. In this context, the search for new therapies that can bring better results to patients is of utmost importance. Protein tyrosine kinases (PTKs) are involved in several biological processes, such as cell growth regulation and proliferation, thus, mutations that affect their functionality can have a great impact on crucial molecular pathways in the cells, leading to tumorigenesis. In the past couple of decades, the use of small-molecule inhibitors, which include tyrosine kinase inhibitors (TKIs), has been a hallmark in the treatment of hematological malignancies, and MM patients may also benefit from TKI-based treatment strategies. In this review, we seek to understand the applicability of TKIs used in MM clinical trials in the last 10 years.

Drug Repurposing by Tumor Tissue Editing

The combinatory use of drugs for systemic cancer therapy commonly aims at the direct elimination of tumor cells through induction of apoptosis. An alternative approach becomes the focus of attention if biological changes in tumor tissues following combinatory administration of regulatorily active drugs are considered as a therapeutic aim, e.g., differentiation, transdifferentiation induction, reconstitution of immunosurveillance, the use of alternative cell death mechanisms. Editing of the tumor tissue establishes new biological 'hallmarks' as a 'pressure point' to attenuate tumor growth. This may be achieved with repurposed, regulatorily active drug combinations, often simultaneously targeting different cell compartments of the tumor tissue. Moreover, tissue editing is paralleled by decisive functional changes in tumor tissues providing novel patterns of target sites for approved drugs. Thus, agents with poor activity in non-edited tissue may reveal new clinically meaningful outcomes. For tissue editing and targeting edited tissue novel requirements concerning drug selection and administration can be summarized according to available clinical and pre-clinical data. Monoactivity is no pre-requisite, but combinatory bio-regulatory activity. The regulatorily active dose may be far below the maximum tolerable dose, and besides inhibitory active drugs stimulatory drug activities may be integrated. Metronomic scheduling often seems to be of advantage. Novel preclinical approaches like functional assays testing drug combinations in tumor tissue are needed to select potential drugs for repurposing. The two-step drug repurposing procedure, namely establishing novel functional systems states in tumor tissues and consecutively providing novel target sites for approved drugs, facilitates the systematic identification of drug activities outside the scope of any original clinical drug approvals.

An update on novel multiple myeloma targets

Introduction: despite therapeutic progress, leading to a significant improvement of outcome, multiple myeloma (MM) remains a difficult to treat hematologic disease due to its biological heterogeneity and clinical complexity.

Areas covered: Treatment of patients refractory and resistant to all classes of agents used in newly diagnosed MM, is becoming a relevant problem for every hematologist. New generation immunotherapies, such as conjugated mAb, bispecific mAbs and CAR-T cells, targeting novel molecules as BCMA, have showed relevant results in very advanced MM. In the same setting, small molecules, such as selinexor and melflufen, also proved to be effective. We are currently waiting for the results of under evaluation personalized therapy, directed against specific gene mutations or signaling pathways, responsible for disease progression.

Expert Opinion: In the near future, many therapeutic strategies will become available for MM and the challenge will be to position each approach in order to cure, maintaining a good quality of life in these patients.

Molecular relation between biological stress and carcinogenesis

This paper aims to overview different types of stress, including DNA replication stress, oxidative stress, and psychological stress. Understanding the processes that constitute a cellular response to varied types of stress lets us find differences in how normal cells and cancer cells react to the appearance of a particular kind of stressor. The revealed dissimilarities are the key for targeting new molecules and signaling pathways in anticancer treatment. For this reason, molecular mechanisms that underlay DNA replication stress, oxidative stress, and psychological stress have been studied and briefly presented to indicate biochemical points that make stressors contribute to cancer development. What is more, the viewpoint in which cancer constitutes the outcome and the cause of stress has been taken into consideration. In a described way, this paper draws attention to the problem of cancer-related post-traumatic stress disorder and proposes a novel, multidimensional oncological approach, connecting anticancer treatment with psychiatric support.

Exploiting the ubiquitin system in myeloid malignancies. From basic research to drug discovery in MDS and AML

The ubiquitin-proteasome system is the crucial homeostatic mechanism responsible for the degradation and turnover of proteins. As such, alterations at this level are often associated with oncogenic processes, either through accumulation of undegraded pathway effectors or, conversely, excessive degradation of tumor-suppressing factors. Therefore, investigation of the ubiquitin- proteasome system has gained much attraction in recent years, especially in the context of hematological malignancies, giving rise to efficient therapeutics such as bortezomib for multiple myeloma. Current investigations are now focused on manipulating protein degradation via fine-tuning of the ubiquitination process through inhibition of deubiquitinating enzymes or development of PROTAC systems for stimulation of ubiquitination and protein degradation. On the other hand, the efficiency of Thalidomide derivates in myelodysplastic syndromes (MDS), such as Lenalidomide, acted as the starting point for the development of targeted leukemia-associated protein degradation molecules. These novel molecules display high efficiency in overcoming the limitations of current therapeutic regimens, such as refractory diseases. Therefore, in this manuscript we will address the therapeutic opportunities and strategies based on the ubiquitin-proteasome system, ranging from the modulation of deubiquitinating enzymes and, conversely, describing the potential of modern targeted protein degrading molecules and their progress into clinical implementation.

SIRPα+ macrophages are increased in patients with FL who progress or relapse after frontline lenalidomide and rituximab

Chemoimmunotherapy is an effective treatment strategy for patients with FL who relapse after frontline R².

SIRPα⁺ and CSF1R⁺macrophages are increased in FL patients who relapse after frontline R².

Limited data exist regarding the outcome of patients with follicular lymphoma (FL) who relapse or progress after frontline lenalidomide and rituximab (R²). Moreover, mechanisms of resistance to R² in FL remain unclear, with increased protumoral macrophages suspected as a major contributory culprit to this phenomenon. This retrospective study analyzed the outcome of patients with advanced-stage FL grade 1 to 3A who relapsed or progressed after frontline R². A multiplex immunofluorescence macrophage panel, including CD47, CD14, CD68, CD115 (also known as colony-stimulating factor 1 receptor [CSF1R]), CD163, CD172a (also known as signal regulatory protein α [SIRPα]), and CD274 (also known as programmed cell death-ligand 1 [PDL1]), was used to stain tissue biopsy specimens collected before initiation of R² and at the time of progression. Among 156 patients with advanced-stage FL treated with frontline R², 33 (21%) relapsed or progressed and required second-line therapy, after a median of 33 months (range, 1-122 months). Second-line therapy was chemoimmunotherapy in 16 (48%) patients and other therapy in 17 (52%). The overall response rate was 78%, and complete response rate was 72%. Median progression-free survival was significantly longer in patients who received chemoimmunotherapy compared with other therapy (99 vs 25 months; P = .004). Three macrophage populations were significantly increased in tissue samples collected at progression compared with before frontline treatment: CD68⁺CD115⁺ (P = .02), CD68⁺CD115⁺CD172a⁺ (P = .02), and CD68⁺CD163⁺CD172a⁺ (P = .01). Chemoimmunotherapy is an effective treatment strategy for patients with FL who relapse after frontline R². Therapies targeting specific macrophage populations may yield novel approaches for improving outcomes with frontline R².

SUMOylation inhibition enhances multiple myeloma sensitivity to lenalidomide

Despite the potent effect of lenalidomide (Len) in multiple myeloma (MM) treatment, patients develop Len resistance leading to progressive disease, demanding an urgent need to investigate the mechanisms mediating Len resistance. Our study identified SUMOylation as a potential mechanism regulating Len resistance in MM. Len-resistant MM cell line MMR10R presented much higher SUMO E1 (SAE2) expression and more global SUMOylation than Len-sensitive MM1S cell line. SUMOylation inhibition by using TAK-981, a novel and specific SUMO E1 inhibitor, significantly enhances myeloma sensitivity to Len in MM cell lines. Moreover, the enhanced anti-MM activity by TAK-981 and Len combination has been validated using primary relapsing MM patient samples. Overexpression of IRF4 and c-Myc is a major mechanism of Len resistance. Len showed limited effect on IRF4 and c-Myc level in Len-resistance cell line, but TAK-981 treatment reduced IRF4 and c-Myc expression in Len-resistant line and caused further decrease when combined with Len. We found SUMOylation inhibition decreases IRF4 at transcriptional and post-translational level. SUMOylation inhibition reduced DOT1L with decreased methylation of histone H3 lysine 79, to suppress IRF4 gene transcription. SUMOylation inhibition also reduced IRF4 protein level by enhancing degradation. Overall, our data revealed SUMOylation inhibition enhances Len sensitivity through downregulating IRF4.

Carfilzomib, dexamethasone, and daratumumab versus carfilzomib and dexamethasone for patients with relapsed or refractory multiple myeloma (CANDOR): updated outcomes from a randomised, multicentre, open-label, phase 3 study

BACKGROUND

Despite recent advances in therapeutic options, there remains an unmet need for treating patients with relapsed or refractory multiple myeloma, especially in those previously exposed or refractory to lenalidomide. This updated efficacy and safety analysis from the phase 3 CANDOR study compared carfilzomib, daratumumab, and dexamethasone (KdD) with carfilzomib and dexamethasone (Kd) in patients with relapsed or refractory multiple myeloma.

METHODS

In this updated analysis of the randomised, multicentre, open-label, phase 3 CANDOR study, patients (aged ≥18 years) with relapsed or refractory multiple myeloma, at least a partial response to between one and three previous therapies, and Eastern Cooperative Oncology Group performance status of 0-2, were recruited from 102 medical centres globally and randomly assigned (2:1) by interactive voice or web response software to receive KdD or Kd. Participants were stratified by disease stage, previous proteasome inhibitor or anti-CD38 antibody exposure, and number of previous therapies. All patients received intravenous infusions of carfilzomib twice per week at 56 mg/m² (20 mg/m² on days 1 and 2 during cycle 1) on days 1, 2, 8, 9, 15, and 16 of each 28-day cycle. Daratumumab (8 mg/kg) was administered intravenously on days 1 and 2 of cycle 1 and at 16 mg/kg weekly for the remaining doses of the first two cycles, then every 2 weeks for four cycles (cycles 3-6), and every 4 weeks thereafter. Patients received 40 mg dexamethasone weekly (20 mg for patients >75 years old). This analysis was a preplanned interim analysis for overall survival; however, at the time of data cutoff, overall survival data were not mature. The primary endpoint was progression-free survival. Here, we provide updated progression-free survival data, assessed centrally by Onyx Response Computer Algorithm in the intention-to-treat population, with 11 months additional follow-up. Adverse events were assessed in the safety population, which included all participants who received at least one dose of trial treatment. CANDOR is registered with ClinicalTrials.gov, NCT03158688, and is active but not recruiting.

FINDINGS

Between June 13, 2017, and June 25, 2018, 466 patients were enrolled, of whom 312 received KdD and 154 received Kd. At data cutoff (June 15, 2020), median follow-up was 27·8 months (IQR 25·6-29·5) for KdD and 27·0 months (13·2-28·6) for Kd. Median progression-free survival was 28·6 months (95% CI 22·7-not estimable [NE]) in the KdD group and 15·2 months (11·1-19·9) in the Kd group (hazard ratio 0·59 [95% CI 0·45-0·78], log-rank p<0·0001). Treatment-emergent adverse events in the safety population were consistent with the primary analysis. Grade 3 or worse treatment-emergent adverse events occurred in 268 (87%) patients in the KdD group and 116 (76%) in the Kd group; most commonly thrombocytopenia (76 [25%] vs 25 [16%], respectively), hypertension (65 [21%] vs 23 [15%]), pneumonia (54 [18%] vs 14 [9%]), and anaemia (53 [17%] vs 23 [15%]). Serious adverse events occurred in 194 (63%) patients with KdD and 76 (50%) with Kd. Adverse events leading to death occurred in 27 (9%) patients in the KdD group and seven (5%) in the Kd group; most commonly septic shock (five [2%] vs one (1%]) and pneumonia (four [1%] vs none). No new treatment-related deaths have occurred since the primary analysis.

INTERPRETATION

A clear, maintained progression-free survival benefit of KdD over Kd with longer follow-up was confirmed, making KdD an emerging standard-of-care for patients with relapsed or refractory multiple myeloma.

FUNDING

Amgen and Janssen.

Recent Progress on Primary Central Nervous System Lymphoma-From Bench to Bedside

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extra-nodal lymphoma. The high relapse rate of PCNSL remains a major challenge to the hematologists, even though patients exhibit high sensitivity to the methotrexate-based chemotherapeutic regimens. Recently, the advent of Bruton's tyrosine kinase inhibitor (BTKi) and CAR T treatment has made more treatment options available to a proportion of patients. However, whether BTKi monotherapy should be given alone or in combination with conventional chemotherapy is still a clinical question. The status of CAR T therapy for PCNSLs also needs to be elucidated. In this review, we summarized the latest progress on the epidemiology, pathology, clinical manifestation, diagnosis, and treatment options for PCNSLs.

Cancer therapies based on targeted protein degradation - lessons learned with lenalidomide

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of 'degrader' drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies.