Despite significant advances in cancer diagnostics and therapeutics the majority of cancer unfortunately remains incurable, which has led to continued research to better understand its exceptionally diverse biology. As a result of genomic instability, cancer cells typically have elevated proteotoxic stress. Recent appreciation of this functional link between the two secondary hallmarks of cancer: aneuploidy (oxidative stress) and proteotoxic stress, has therefore led to the development of new anticancer therapies targeting this emerging “Achilles heel” of malignancy. This review highlights the importance of managing proteotoxic stress for cancer cell survival and provides an overview of the integral role proteostasis pathways play in the maintenance of protein homeostasis. We further review the efforts undertaken to exploit proteotoxic stress in multiple myeloma (as an example of a hematologic malignancy) and triple negative breast cancer (as an example of a solid tumor), and give examples of: (1) FDA-approved therapies in routine clinical use; and (2) promising therapies currently in clinical trials. Finally, we provide new insights gleaned from the use of emerging technologies to disrupt the protein secretory pathway and repurpose E3 ligases to achieve targeted protein degradation.

Purpose: To investigate the efficacy and safety of the novel orally active PI3Kδ inhibitor in relapsed and/or refractory patients with follicular lymphoma (FL) who had received at least two prior systemic treatments. Patients and Methods: Histologically confirmed relapsed and/or refractory patients with FL with disease progression after receiving second-line or greater systemic therapy were enrolled. Linperlisib was administered at 80 mg every day, orally in a 28-day cycle until disease progression or intolerable toxicity occurred. The primary outcome for the study was the objective response rate (ORR), with secondary outcomes including the duration of response (DOR), progression-free survival (PFS), overall survival (OS), disease control rate, and drug safety profile. Results: Of 114 screened relapsed and/or refractory patients with FL, 84 were enrolled in the full analysis set (FAS). The ORR of the 84 FAS patients was 79.8% [95% confidence interval (CI), 69.6–87.8, 67 patients], with 13 patients (15.5%) achieving a complete response and 54 patients (64.3%) with a partial response. The median DOR was 12.3 months (95% CI, 9.3–15.9). The median PFS was 13.4 months (95% CI, 11.1–16.7). The 12-month OS rate was 91.4% (95% CI, 82.7–95.8) and a median OS not reached by 42 months. The most frequent (>3%) treatment-related adverse events Grade ≥3 were infectious pneumonia (19.0%), neutropenia (15.5%), decreased lymphocyte count (4.8%), decreased leukocyte count (4.8%), increased lipase (3.6%), decreased platelet count (3.6%), hypertriglyceridemia (3.6%), and interstitial lung disease (3.6%). Conclusions: Linperlisib demonstrated compelling clinical activity and manageable tolerability for relapsed and/or refractory patients with FL who had received at least two prior systemic therapies.

B cell lymphoma and multiple myeloma (MM) are the most common hematological malignancies which benefit from therapeutic monoclonal antibodies (mAbs)-based immunotherapies. Despite significant improvement on patient outcome following the use of novel therapies for the past decades, curative treatment is unavailable for the majority of patients. For example, the 5-year survival of MM is currently less than 50%. In the 1980s, interferon-α was used as monotherapy in newly diagnosed or previously treated MM with an overall response rate of 15–20%. Noticeably, a small subset of patients who responded to long-term interferon-α further achieved sustained complete remission. Since 1990, interferon-α-containing regimens have been used as a central maintenance strategy for patients with MM. However, the systemic administration of interferon-α was ultimately limited by its pronounced toxicity. To address this, the selective mAb-mediated delivery of interferon-α has been developed to enhance specific killing of MM and B-cell malignant cells. As such, targeted interferon-α therapy may improve therapeutic window and sustain responses, while further overcoming suppressive microenvironment. This review aims to reinforce the role of interferon-α by consolidating our current understanding of targeting interferon-α with tumor-specific mAbs for B cell lymphoma and myeloma.

Objective: Despite the availability of new agents, elderly patients with multiple myeloma (MM) usually present with poor outcomes due to the heterogeneity of disease conditions, especially immune deficiency. Regulatory B cells (Bregs) can be involved in immune defects by exerting immune regulatory functions in MM. In order to provide more evidence‐based practice for the elderly MM, the study established and assessed a stratified therapeutic model with studies on Bregs for Chinese Elderly Multiple Myeloma in 2021 (CEMM2021).Methods: In this open‐label, non‐interventional, prospective study in the real world, 159 newly diagnosed MM (NDMM) patients over 65 years old were sequentially recruited and bone marrow aspirates prior to treatment were obtained to detect the ratios of Bregs by flow cytometry.Results: Based on the CEMM2021 model, 147 patients had received at least one cycle of induction therapy, including bortezomib/dexamethasone (Bd) (n = 80), lenalidomide/dexamethasone (Rd) (n = 27), Bd with a third agent X (Bd + X) (n = 27), and other regimens (n = 13). The proportions of patients achieving very good partial response or better were comparable among Bd, Bd + X, and Rd groups (41.9% vs. 54.5% vs. 44.0%, p = 0.472). Besides, the progression‐free survival (PFS) and overall survival (OS) were not significantly different among Rd, Bd, and Bd + X groups. Multivariable analysis showed that induction efficacy less than partial response (PR) were poor prognostic factors for PFS, while Revised‐International Staging System (R‐ISS) III and efficacy less than PR were poor prognostic factors for OS. This study also found that the ratios of bone marrow Bregs 4.2 (p = 0.000) were closely correlated with OS in the elderly MM.Conclusions: For the elderly NDMM, the CEMM2021 algorithm in our center might provide a valuable reference for the guidance of therapeutic strategies, with the combination of Bregs resulting in an effective and clinically meaningful prediction in contemporary treatment.

Background: Since no randomized controlled trials have directly compared the efficacy and safety of immunotherapy with daratumumab versus lenalidomide/bortezomib/dexamethasone (RVD) in the frontline treatment of transplant-ineligible newly diagnosed multiple myeloma (TIE-NDMM), this study systematically reviewed the clinical studies regarding immunotherapy with daratumumab and RVD regimen in the treatment of TIE-NDMM to explore the optimization direction of the best first-line therapy.Methods: The Cochrane Library, PubMed, Embase, and Web of Science databases were searched to collect studies on regimens containing daratumumab or RVD/RVD-lite for TIE-NDMM. Pooled and meta-analysis was then performed to compare the overall response rate (ORR), stringent complete remission (sCR) and CR rate, progression-free survival (PFS), overall survival (OS) and treatment-related discontinuation rate between daratumumab-containing immunotherapy regimen and RVD/RVD-lite regimen by using R 4.3.1 software.Results: Nine prospective clinical trials were included, including 1795 TIE-NDMM or NDMM without intent for immediate ASCT. Among them, 938 patients were treated with daratumumab-based immunotherapy and 857 with RVD/RVD-lite regimens. Meta-analysis results showed that The daratumumab-based regimen showed a significantly higher CR/sCR rate than RVD/RVD-lite for TIE-NDMM (47% vs. 24%, P<0.01). The median PFS of the daratumumab-based and RVD/RVD-lite groups were 52.6 months and 35.1 months respectively (HR 0.77, 95%CI, 0.66-0.90). The median OS of both groups was not reached, and there were no significant differences in OS between the two groups (HR 1.03, 95%CI, 0.86-1.23). The therapy discontinuation rate led by adverse events was significantly higher in the RVD/RVD-lite group than in the daratumumab-based regimen group for the TIE-NDMM (16% vs. 7%, P=0.03).Conclusion: This meta-analysis suggests that daratumumab-containing immunotherapy is superior to RVD in the depth of treatment efficacy, progression-free survival, and lower treatment-related discontinuation rates. Limited by the lack of head-to-head clinical trials, this conclusion needs to be verified by concurrent cohort studies.

Multiple myeloma (MM) is a heterogeneous disease that remains incurable with significant interpatient variability in outcomes. Regulatory B cells (Bregs) were observed to be involved into specific defects in MM. Here, we provide our risk-adapted approach to newly diagnosed MM (NDMM), combining with the fundamental dysfunction of Bregs. We reported one hundred consecutive patients with NDMM from South-Western China, primarily treated with bortezomib plus dexamethasone with or without a 3^rd agent, were enrolled from 2017. Bone marrow aspirates were obtained and flow cytometry (FCM) was used to quantify the percentage of Bregs from the bone marrow. The correlation between Bregs and clinical characters were further analyzed. This study found using bortezomib plus dexamethasone as backbone showed promising efficacy with acceptable tolerability in NDMM. The relatively compromised progression free survival (PFS) points to the essential synergy of bortezomib and lenalidomide here. This study also found that altered proportions of Bregs were closely correlated with treatment efficacy and prognosis in MM. Further understanding of Bregs biology might provide new opportunities to develop immunotherapy, which could prove beneficial in treating MM.