Combination Of Proteasome Inhibitors Research Articles

A single-day polychemotherapy regimen with proteasome inhibitor combinations for relapsed/refractory myeloma in the era of novel therapies.

PCAB (prednisone, cyclophosphamide, doxorubicin, carmustine) is a single-day regimen previously used for induction and now in relapsed/refractory multiple myeloma (RRMM). We retrospectively analysed the outcomes of 85 patients from five Australian centres. These included 30 patients (35.3%) who received PCAB with one additional agent (bortezomib most frequently). Median age of the patients was 65 years (37-80), with a median of four (1-8) prior lines of therapy. ORR was 37% (CR 4.9%). Median progression free survival and overall survival were 4.4 months (95% CI 3.5-6.7) and 7.4 months (95% CI 6.4-10.2), respectively. Extramedullary disease (EMD) was associated with shorter survival. Grade 3 or 4 cytopenia and febrile neutropenia occurred in 76.2% and 39.1%, respectively, with six (7.1%) treatment-related mortalities. Median inpatient stay was 3.3 days/28-day cycle (IQR 0.6-13), and for patients who died, a median of 20.2% of days alive were spent inpatient (IQR 6.4-39.1%). Three patients were successfully bridged to CAR T-cell therapy using PCAB, despite being penta-exposed and having EMD. PCAB may be considered as a useful salvage therapy amongst other polychemotherapy regimens in late relapse. Further studies is warranted to investigate and define its role as a bridging therapy to novel therapeutics.

A Randomized Phase II Study of Daratumumab, Ixazomib, and Dexamethasone (DId, Arm A) Vs Daratumumab, Bortezomib and Dexamethasone (DVd) Followed By Daratumumab, Did (Arm B) in Newly Diagnosed Multiple Myeloma (DeRIVE) Study

Introduction: The safety and efficacy established by daratumumab (a CD38 monoclonal antibody)-based induction therapies for both transplant-eligible myeloma patients (based on CASSIOPEIA, and GRIFFIN trials) and transplant-ineligible patients (based on MAIA trial) have gained an accelerated momentum for adoption into regular clinical practice. In this context, to find the most optimal non-IMID based daratumumab-combination therapy as induction, we conducted a randomized phase 2 study to evaluate the safety and efficacy for in-class transition from bortezomib to ixazomib, stratified by transplant-eligibility and R-ISS. Methods: Patients were randomized to receive Arm A [daratumumab, ixazomib and dexamethsone (DId) X 8 cycles)] or Arm B [(daratumumab, bortezomib and dexamethsone (DVd) x 3) followed by (DId x 5 cycles)] for the primary endpoint of ≥ very good partial response rate (VGPR) rate post-induction cycle 8. Several other secondary endpoints were evaluated including safety, overall repsonse rate (ORR), progression free survival (PFS) and overall survival (OS). Standard dosing schedule was used [DId: daratumumab IV 16 mg/kg on days 1, 8, 15, 22 every 28 days x 2 cycles; then on days 1, 15 every 28 days x 6 cycles and every 28 days during maintenance (or 1800 mg SC at the same schedule), ixazomib - 4 mg PO on Days 1, 8, and 15 every 28 days and dexamethasone - 40 mg PO on days 1, 8, 15 and 22 every 28 days; DVd: daratumumab IV 16 mg/kg on days 1, 8, 15, 22 every 28 days x 2 cycles; then on days 1, 15 every 28 days x 6 cycles and every 28 days during maintenance (or 1800 mg SC at the same schedule), bortezomib - 1.3 mg/m2 SC on days 1, 4, 8 and 11 every 21 day and dexamethasone - 40 mg PO on days 1, 8, 15 and 22 every 28 days]. Transplant eligible patients may receive stem cell collection and transplant after cycle 8. During the maintenance phase, patients receive DId as maintennace therapy for a total of 32 cycles. 52 subjects were enrolled at Winship Cancer Institute of Emory University between 07/2019 and 05/2022. Results: The median age was 64 years for the 48 evaluable subjects [25 (52%) in arm A, 68 (48-87) and 23 (48%) in arm B, 61 (37-80), p<0.25]. 56% of the cohort was male (64 vs 48%, p=0.20), 48% were black (40% vs 56.5%, p=0.245). 20.8% had t(11;14), 29.2% had 1q abnormalities, 70.8% had hyperdiploidy, 25% had complex karyotype and 10.4% were high-risk [defined as presence of del17p, t(4;14) or t(14;16)]. 38 (81%) patients underwent an autologous stem cell transplant (72% in Arm A and 90.9% in Arm B, p=1.00). The primary endpoint favored arm B (Arm A vs Arm B ≥VGPR rate: 28% vs 56.5%, p<0.043). Similarly, the ORR favored arm B as well (Arm A vs Arm B ORR: 76% vs 95.7%, p<0.062). Post transplant ≥VGPR rates and ORR were 88.9% vs 95%, p=0.458 and 100% vs 100%, p=NS, respectively. At a median follow up of 35.2 months, 80% of the patients remain progression free as shown in figure 1. The adverse event profile was similar across both cohorts (grade 3/4 events occurred in 6 (24%) vs 7 (30%) for Arm A and B, respectively, p=0.27). There was no grade 3/4 peripheral neuropathy (PN), though grade 1/2 PN were higher in Arm B. There were two secondary primary malignancy reported in Arm B (prostate adenocarcinoma, esophageal adenocarcinoma). All together the safety signals were comparable between both arms. Conclusion: This is one of the first studies showing the safety and efficacy of non-IMID based dara-combination induction therapies with in-class transition of bortezomib to ixazomib yielding higher response rates post-induction and post-transplant without compromising on the safety. 3-year PFS rate of close to 80% across both arms is for daratumumab and proteasome inhibitor combination therapy are highly encouraging and may be an alternative regimen for patients that may not tolerate IMIDs or that have a contraindication to receive IMIDs.

Patient-derived MicroOrganoSpheres (MOS) and precision clinical decision-making for patients with multiple myeloma.

8047 Background: There are many multiple myeloma (MM) treatments and nearly all patients undergo continual cycles of treatment, response, and resistance. Selecting an effective therapeutic strategy is of critical importance; but there is currently a lack of patient-derived MM models that can enable functional precision medicine to help real-time clinical decision-making to guide individual patient treatment. Methods: We show a method to rapidly establish MM patient-derived MicroOrganoSheres (MOS), which are microscale, droplet-sized patient avatars that sustain the native tumor niche, including both stromal and immune compartments. We generated first-of-its-kind data showing that MM MOS predicted patient treatment outcomes and have the potential to guide clinical treatment decisions. We further developed high-throughput drug screen to demonstrate MM MOS response to FDA-approved single and combination therapies and developed MOS assays to predict patient responses to immunotherapies including bispecific and phagocytosis-inducing antibodies. Results: MM MOS established from patient bone marrow (BM) biopsies preserved CD138/CD38 tumor cells, stromal (e.g., osteoblast) cells, and all major immune cell populations (T, NK, B, macrophage, dendritic, and myeloid-derived suppressor cells) for 11 days in culture. We performed single and combo drug testing on MOS derived from 7 MM patients within 10 days of biopsy collection. Patients went on receiving treatments and their responses were assessed using International Myeloma Working Group response criteria. The MOS assay predicted responses of both treatment-naïve and refractory patient to standard-of-care regimens, including combinations of proteasome inhibitors (bortezomib, carfilzomib), immunomodulatory agents (lenalidomide) and DCEP. Moreover, the BM biopsy-derived MOS enabled high-throughput drug testing of single agents and combinations in 9-dose titrations, providing clinicians the ability to evaluate alternative treatment options. Furthermore, because MOS retain the immune compartments of the original tumor niche, we were able to evaluate patients’ response to bispecific T cell engagers and developed a phagocytosis assay to measure anti-tumor phagocytosis activity, which showed efficacy in both single-agent and combo settings. Multi-modal profiling and an AI image analysis pipeline provided robust measurements that confirmed the unique phenotypic profile of each patient sample, highlighting the critical unmet need to guide each patient to the optimal treatment. Conclusions: Based on this groundbreaking feasibility study, a subsequent clinical trial of 40 patients is current under IRB review to further validate the clinical power of MM MOS to predict patient outcome and to demonstrate utility as a viable functional precision medicine approach to inform treatment decisions in the clinic.

Association of venetoclax-based therapy with increased survival in multiple myeloma (MM) harboring t(11;14): A single-center experience.

e20055 Background: The BCL-2 inhibitor venetoclax (Ven) has shown activity in MM with t(11;14). However, a randomized trial comparing bortezomib and dexamethasone ± Ven in unselected MM patients was notable for decreased overall survival (OS) in the non-t(11;14) population treated with Ven despite improved progression free survival (PFS). In a subgroup analysis of 35 t(11;14) patients, those randomized to the Ven arm had superior OS (HR, 0.61 [95% CI, 0.16-2.32]) but this did not reach statistical significance (Kumar et al, Blood 2021). We sought to investigate the real-world impact of Ven-based therapy in t(11;14) MM and to explore patient and disease-related factors impacting response and durability. Methods: We retrospectively identified all t(11;14) MM patients treated at Moffitt Cancer Center between 2000-2022. The primary endpoint was OS measured from the time of MM diagnosis compared between Ven-treated patients and those who did not receive Ven. Secondary endpoints were ≥VGPR rate, PFS, and key toxicities. The era of MM diagnosis (5-year intervals) was included in analyses to account for novel therapies. Kaplan-Meier estimates and Cox regression were employed. Results: 262 MM patients were included. Median age was 64 years (interquartile range [IQR], 56-71 years); 61% were male; 87% were White. Ven was used in 78 patients (30%) on median in the 5th line (IQR, 4-7) and most commonly in combination with anti-CD38 antibodies (42%) or proteasome inhibitor (32%). Most patients (77%) initiated treatment at 400 mg daily and 25% required dose reduction. At a median follow-up of 52 months, 18 (23%) patients died in the Ven group as compared to 87 (47%) in the non-Ven group. Median unadjusted OS was longer in the Ven group (206 months [95% CI, 112-249 months] vs 75 months [95% CI, 65-97 months]; p < 0.01). In multivariable analysis accounting for demographics, high-risk cytogenetics, time of diagnosis, penta-exposed status, autologous stem cell transplant and BCMA-directed therapy, Ven was associated with a reduced risk of death (HR, 0.26; 95% CI, 0.15-0.47). Of 73/78 with available response data, 38% achieved ≥VGPR with Ven-based therapy. Median PFS was 27 months (95% CI, 13-39 months). In univariable analyses, 1q amplification/gain was associated with inferior PFS (13 months [95% CI, 6.5-28 months]) vs 33 months [95% CI, 23 months-not reached/NR]; p = 0.04). Median PFS was longer anti-CD38 antibody (33 months [95% CI, 13 months-NR]) compared to proteasome inhibitor combinations (11 months [95% CI, 7 months-NR]), but this difference was not statistically significant (p = 0.1). No grade 3/4 infections or deaths were directly attributable to Ven. Conclusions: In this real world dataset, MM patients with t(11;14) treated with Ven-based combinations exhibited superior survival. The response to Ven may be impacted by the partner agent and concurrent cytogenetic abnormalities.

Sec61 blockade therapy overrides resistance to proteasome inhibitors and immunomodulatory drugs in multiple myeloma.

Multiple Myeloma (MM) is an incurable neoplasm of mature B cells and the second most prevalent hematological malignancy worldwide. While combinations of proteasome inhibitors like bortezomib (Bz) and immunomodulators (IMiDs) like lenalinomide (Len) are generally effective in newly diagnosed patients, some do not respond to this first-line therapy, and all others will eventually become drug resistant. We previously reported that inhibiting the Sec61 translocon with mycolactone synergizes with Bz to induce terminal unfolded protein response in MM cells, irrespective of their resistance to proteasome inhibition. Here, we examined how Sec61 blockade interferes with IMiD action and whether it overrides resistance to Len. With this aim, we knocked out the IMiD target CRBN in the MM1S cell line and a Bz-resistant subclone to generate Len- and Len/Bz-resistant daughters, respectively. Both the Len- and Len/Bz-resistant clones were susceptible to mycolactone toxicity, especially the doubly resistant one. Notably, the synergy between mycolactone and Bz was maintained in these two clones, and mycolactone also synergized with Len in the two Len-susceptible ones. Further, mycolactone enhanced the therapeutic efficacy of the Bz/Len combination in both mice engrafted with parental or double drug resistant MM1S. Together, these data consolidate the interest of Sec61 blockers as new anti-MM agents and reveal their potential for treatment of refractory or relapsed MM.

Assessing Time to Diagnosis, End-Organ Damage and Treatment Response in Young Newly Diagnosed Multiple Myeloma Patients

Introduction Multiple myeloma (MM) primarily affects older adults, with a median age of 69 years at time of diagnosis. Presenting symptoms of MM are often vague and nonspecific, such as fatigue or musculoskeletal pain, which can delay diagnosis. This may result in irreversible end-organ damage caused by MM, notably renal insufficiency and lytic bone lesions resulting in pathologic fractures, in addition to the reversible anemia and hypercalcemia that are hallmarks of the disease. Those younger than age 50 represent only 5% of patients living with MM. Though they remain in the minority, the incidence in young patients is rising. Data regarding initial presentation, cytogenetics, and rates of end-organ damage are poorly described, and most information arises from individual case reports or small series. In this study, we performed a retrospective analysis of newly diagnosed MM patients at the age of 51 or younger to characterize this distinct population. Methods Patients were identified using automated data capture techniques and manually reviewed. All treatment-eligible patients with MM presenting to UC Davis Medical Center between January 2014 to July 2021 were assessed, regardless of diagnosis date. The diagnosis of multiple myeloma was established according to the IMWG criteria, and patients < 51 years were included. Exclusion criteria included patients with non-histologically confirmed MM. Time of symptom onset was defined as the first medical evaluation with documentation of symptoms or radiographic/laboratory abnormalities which could be ascribed to MM as ascertained through chart review. Baseline diabetes, hypertension and coronary artery disease (comorbidities) were tabulated. Myeloma-related complications were defined as hypercalcemia (serum calcium >11 mg/dL), renal insufficiency (serum creatinine >2mg/dL), anemia (hemoglobin <10g/dL), and bone lesions (one or more osteolytic lesion on skeletal radiography, CT, PET/CT, or MRI) at time of diagnosis. Results 123 patients were included in the study, and their baseline demographics are described in Table 1. The median age was 46.0 years, with a range from 27.8 to 50.9 years; 19 (15%) were age <40. Hypertension was seen in 27 (22%) patients, 7 (5.7%) had diabetes while 93 (74%) had no comorbidities. The most common presenting symptom was musculoskeletal pain 79% of patients. Other presenting manifestations included anemia (13%), fatigue (12%), bacterial infections (8.9%), and weight loss (5.7%). The median time from symptom onset to diagnosis was 1.47 months, with a range of 0 to 49.7 months. Clinical characteristics at diagnosis are described in Table 2. Among the 79 patients with R-ISS staging, 18% had R-ISS Stage I, 70% had Stage II, and 13% had Stage III. Of the 105 patients with cytogenetics data, 19% were high-risk, del(17p) , t(4;14), and/or t(14;16), while 20% had a +1q. For myeloma-related complications, 14 (11%) had hypercalcemia, 16 (13%) renal insufficiency, and 41 (33%) anemia, 95 (77%) of patients had lytic lesions, and 62 (50%) patients presented with fractures. Of these, 31 had spinal compression fractures, 12 had extra-axial pathologic fractures, and 9 had both. Median time from diagnosis to treatment was 0.60 months, with a range of 0 to 23.93 months. The most common induction regimens, received by 64 (52%) of patients, were immunomodulatory drug and proteasome inhibitor combinations. This is followed by CyBorD (20 patients, 16%) and doublet or other therapy (39 patients, 32%). Autologous stem cell transplantation was utilized by 89 (71%) patients, with 19 (15%) receiving a second transplant. The median age at first transplant was 45.7 years, and 49.8 years at second transplant. Conclusion We describe one of the largest cohorts of MM patients diagnosed under the age of 51. While on average we did not observe a significant delay between symptom onset and diagnosis, there were some notable outliers. The presenting symptoms and rates of end-organ damage were similar to what has previously been described in older cohorts, though fractures were more common. Transplant was more frequently used than the general population. Additional study on this population is needed to better understand treatment patterns and barriers to their care. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Paraskeletal and extramedullary plasmacytomas in multiple myeloma at diagnosis and at first relapse: 50-years of experience from an academic institution

From January 1970 to December 2018, 1304 patients were diagnosed with multiple myeloma (MM) at our institution and 256 (19.6%) had plasmacytomas (Ps) (paraskeletal –PPs- 17.6%, extramedullary –EMPs-1.9%). Patients with Ps had lower serum M-protein and less advanced ISS stage than those without. At first relapse, 192 out of 967 patients (19.8%) developed Ps (PPs 14.6%, EMPs 5.1%). The only factor associated with Ps at relapse was the presence of Ps at diagnosis (46% vs 13%, p < 0.00001) with no impact with exposure to novel drugs or previous autologous stem-cell transplantation (ASCT). The median overall survival (OS) was 45, 44 and 20 months for patients without Ps, PPs and EMPs, respectively (p = 0.013). Patients with PPs who underwent ASCT had similar OS than those without Ps (98 vs. 113 months) and significantly longer than those with EMPs (98 vs 47 months, p = 0.006). In patients non-eligible for ASCT the presence of PPs or EMPs was associated with shorter OS compared with patients without Ps (32 vs. 24 vs. 6 months, p = 0.009). In the relapsed setting, a significant survival benefit was observed beyond the year 2000, but still with significant differences among patients without Ps, PPs and EMPs (37 vs 22 vs 16 months, p = 0.003). Importantly, rescue therapy with combinations of proteasome-inhibitors plus immunomodulatory drugs was associated with prolonged OS from first relapse (over 6 years), even in patients with EMPs.

Network meta-analysis of randomized trials in multiple myeloma: Efficacy and safety in frontline therapy for patients not eligible for transplant.

The treatment scenario for newly-diagnosed transplant-ineligible multiple myeloma patients (NEMM) is quickly evolving. Currently, combinations of proteasome inhibitors and/or immunomodulatory drugs +/- the monoclonal antibody Daratumumab are used for first-line treatment, even if head-to-head comparisons are lacking. To compare efficacy and safety of these regimens, we performed a network meta-analysis of 27 phase 2/3 randomized trials including a total of 12,935 patients and 23 different schedules. Four efficacy/outcome and one safety indicators were extracted and integrated to obtain (for each treatment) the surface under the cumulative ranking-curve (SUCRA), a metric used to build a ranking chart. With a mean SUCRA of 83.8 and 80.08 respectively, VMP+Daratumumab (DrVMP) and Rd+Daratumumab (DrRd) reached the top of the chart. However, SUCRA is designed to work for single outcomes. To overcome this limitation, we undertook a dimensionality reduction approach through a principal component analysis, that unbiasedly grouped the 23 regimens into three different subgroups. On the bases of our results, we demonstrated that first line treatment for NEMM should be based on DrRd (most active, but continuous treatment), DrVMP (quite "fixed-time" treatment), or, alternatively, VRD and that, surprisingly, melphalan as well as Rd doublets still deserve a role in this setting.

Abstract 5455: Nuclear export inhibitor selinexor synergizes with proteasome inhibitor marizomib in preclinical models of glioblastoma

Abstract Background: Glioblastoma (GBM) is an aggressive brain cancer with poor prognosis and limited treatment options. Selinexor is a first-in-class oral inhibitor of Exportin 1 (XPO1/CRM1) with broad anti-cancer activities and is clinically approved to treat multiple myeloma and diffuse large B cell lymphoma. In a phase 2 study of recurrent GBM, monotherapy of selinexor demonstrated clinically relevant disease control (Lassman 2021 Clin Cancer Res). Our previous preclinical studies identified synergy between selinexor and proteasome inhibitors in GBM in vitro. Among the proteasome inhibitors tested, we chose to focus on marizomib due to its ability to cross the blood-brain-barrier, supporting its use in GBM. We tested GBM cell lines and mouse xenograft models to evaluate the anti-GBM effects of selinexor and marizomib in combination. Methods: Cytotoxic effects of selinexor and marizomib were evaluated with two GBM cell lines LN18 and U87MG. The anti-GBM effects of selinexor and marizomib were further investigated in vivo with U87MG mouse xenograft models of GBM. Female nude mice carrying U87MG subcutaneous implants were treated with vehicle, selinexor, marizomib or the combination of the two agents (six mice per treatment group). Tumor volume and body weight were monitored throughout the study. Tumor samples were collected at the end of the study for transcriptomic analysis and immunohistochemistry tests. Results: Synergistic anti-GBM effects of selinexor and marizomib were observed in both LN18 and U87MG cells in vitro. In mouse xenograft models of U87MG, tumor growth was significantly inhibited by selinexor and marizomib single agents relative to controls, at Day 15 of the study, tumor growth inhibition (TGI) was 60.0% (p=0.0009) for selinexor (10 mg/kg, once per week), 49.2% (p=0.0069) for marizomib once weekly at 75 µg/kg, and 33.1% (p=0.0991) for marizomib once every 2 weeks at 75 µg/kg. Synergistic anti-GBM effect was observed in the combination groups, with a TGI of 99.6% (p&amp;lt;0.0001) for selinexor with once weekly marizomib, and a TGI of 90.0% (p&amp;lt;0.0001) for selinexor with once every other week marizomib. Conclusions: Synergistic anti-GBM effects of selinexor and marizomib in preclinical models warrants further investigation. The synergism is likely due to enhanced inhibition of the NFκB signaling pathways as previously demonstrated for selinexor and proteasome inhibitor combination. Citation Format: Hua Chang, Leah Henegar, Christopher J. Walker, Trinayan Kashyap, Marie Maloof, Feng Wang, Kathleen Martyn, Shira Orr, Sharon Tamir, Michael G. Kauffman, Sharon Shacham, Yosef Landesman. Nuclear export inhibitor selinexor synergizes with proteasome inhibitor marizomib in preclinical models of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5455.

An Integrated Approach Reveals DNA Damage and Proteotoxic Stress as Main Effects of Proton Radiation in S. cerevisiae.

Proton radiotherapy (PRT) has the potential to reduce the normal tissue toxicity associated with conventional photon-based radiotherapy (X-ray therapy, XRT) because the active dose can be more directly targeted to a tumor. Although this dosimetric advantage of PRT is well known, the molecular mechanisms affected by PRT remain largely elusive. Here, we combined the molecular toolbox of the eukaryotic model Saccharomyces cerevisiae with a systems biology approach to investigate the physiological effects of PRT compared to XRT. Our data show that the DNA damage response and protein stress response are the major molecular mechanisms activated after both PRT and XRT. However, RNA-Seq revealed that PRT treatment evoked a stronger activation of genes involved in the response to proteotoxic stress, highlighting the molecular differences between PRT and XRT. Moreover, inhibition of the proteasome resulted in decreased survival in combination with PRT compared to XRT, not only further confirming that protons induced a stronger proteotoxic stress response, but also hinting at the potential of using proteasome inhibitors in combination with proton radiotherapy in clinical settings.

Geranylgeranyl diphosphate synthase inhibitor and proteasome inhibitor combination therapy in multiple myeloma

BackgroundMultiple myeloma (MM) remains an incurable malignancy, despite the advent of therapies such as proteosome inhibitors (PIs) that disrupt protein homeostasis and induce ER stress. We have pursued inhibition of geranylgeranyl diphosphate synthase (GGDPS) as a novel mechanism by which to target protein homeostasis in MM cells. GGDPS inhibitors (GGSI) disrupt Rab geranylgeranylation, which in turn results in perturbation of Rab-mediated protein trafficking, leading to accumulation of intracellular monoclonal protein, induction of ER stress and apoptosis. Our lead GGSI, RAM2061, has demonstrated favorable pharmacokinetic properties and in vivo efficacy. Here we sought to evaluate if combination therapy with GGSI and PI would result in enhanced disruption of the unfolded protein response (UPR) and increase anti-MM efficacy.MethodsMTT assays were conducted to evaluate the cytotoxic effects of combining RAM2061 with bortezomib in human MM cells. The effects of RAM2061 and/or PI (bortezomib or carfilzomib) on markers of UPR and apoptosis were evaluated by a combination of immunoblot (ATF4, IRE1, p-eIF2a, cleaved caspases and PARP), RT-PCR (ATF4, ATF6, CHOP, PERK, IRE1) and flow cytometry (Annexin-V). Induction of immunogenic cell death (ICD) was assessed by immunoblot (HMGB1 release) and flow cytometry (calreticulin translocation). Cell assays were performed using both concurrent and sequential incubation with PIs. To evaluate the in vivo activity of GGSI/PI, a flank xenograft using MM.1S cells was performed.ResultsIsobologram analysis of cytotoxicity data revealed that sequential treatment of bortezomib with RAM2061 has a synergistic effect in MM cells, while concurrent treatment was primarily additive or mildly antagonistic. The effect of PIs on augmenting RAM2061-induced upregulation of UPR and apoptotic markers was dependent on timing of the PI exposure. Combination treatment with RAM2061 and bortezomib enhanced activation of ICD pathway markers. Lastly, combination treatment slowed MM tumor growth and lengthened survival in a MM xenograft model without evidence of off-target toxicity.ConclusionWe demonstrate that GGSI/PI treatment can potentiate activation of the UPR and apoptotic pathway, as well as induce upregulation of markers associated with the ICD pathway. Collectively, these findings lay the groundwork for future clinical studies evaluating combination GGSI and PI therapy in patients with MM.

Efficacy of first-line treatment options in transplant-ineligible multiple myeloma: A network meta-analysis

Despite major therapeutic advances, the rational choice of the most appropriate first-line regimen in newly diagnosed transplant-ineligible multiple myeloma (TIE-MM) is currently undefined. We aimed to identify the most effective first-line treatment for TIE-MM patients. A total of 37 articles, including 34 treatments and 16,681 patients, were included in this Bayesian network meta-analysis. The outcomes of interest were risk ratios (RR) for progression-free survival (PFS) and overall survival (OS). Based on surface under cumulative ranking curve values, daratumumab-bortezomib-melphalan-prednisone (Dara-VMP) and daratumumab-lenalidomide-dexamethasone (Dara-Rd28) showed superiority compared to other combinations regarding 12-, 24-, 36-, and 48-month PFS. Dara-VMP also ranked first for 12-, 24-, 36-, and 48-month OS. Our finding supports the incorporation of daratumumab into first-line regimens. Additionally, these results highlight the relative benefit of incorporating novel agents like monoclonal antibodies, immunomodulatory derivatives, and proteasome inhibitors in combination with the currently existing treatment options.

Safety and Efficacy of Combination Maintenance Therapy with Ixazomib and Lenalidomide in Post-Transplant Myeloma Patients

Safety and Efficacy of Combination Maintenance Therapy with Ixazomib and Lenalidomide in Post-Transplant Myeloma Patients

Outcomes Among Primary Refractory Multiple Myeloma Patients in the Era of Monoclonal Antibodies: The Yale Experience

Introduction: Multiple myeloma (MM) is an incurable yet highly heterogeneous disease of clonal plasma cells. The role of induction therapy is to achieve a complete response, thereby reducing the number of malignant plasma cells in the bone marrow. Partial responses or less are considered suboptimal and are associated with poorer outcomes. Following the approval of monoclonal antibody (mAb) therapies in MM, little is known of their effect on primary refractory and suboptimal responses in real-world populations.Methods: This retrospective cohort study included patients with clinical MM who were diagnosed and treated within the Yale New Haven Health System between 2009-2019. Our primary aim was to evaluate the overall survival (OS) in patients with primary refractory (PriRef) or suboptimal responding disease compared to those who achieved at least a very good partial response (≥VGPR). PriRef disease was assessed following three months of induction therapy, and was defined as a partial response, stable disease, or progressive disease based on International Myeloma Working Group (IMWG) criteria. A stricter cutoff of less than a VGPR was chosen for our definition of PriRef, because deeper responses, including MRD-negative status, have demonstrated increasingly important prognostic value. Descriptive statistics and OS analysis were performed with 2-tailed contingency χ²-tests, t-tests, Kaplan Meier, and log-rank tests using GraphPad Prism v8.Results: 246 patients (pts) with adequate response data following 3 months of induction therapy were identified. Clinical features included median age at diagnosis of 61 years (range, 34-92), 26.8% of whom were 70 years or older, 54.9% male, 63.4% Caucasian, 24.3% Black or African American, and 11% Hispanic. 46.8% had International Staging System (ISS) stage II or III disease and 41.1% had Revised International Staging System (R-ISS) stage II or III disease. 33.3% of patients had high-risk cytogenetics, which was defined as a del17/17p, t(4:14), t(4;16), t(4;20), gain or amplification of 1q, deletion of 1p, and chromosome 1 translocations. 81.7% of this cohort received a triplet or quadruplet induction regimen. The majority of patients received triplet induction regimens that included immunomodulatory and proteasome inhibitor combinations, and only two patients were prescribed quadruplet therapy. 44.7% of patients received autologous stem cell transplant (ASCT) at some point in their treatment course, with 79.1% (87/110) in the upfront setting and 20.9% (23/110) having delayed ASCT (Table 1).In this cohort, 122 pts (49.6%) achieved ≥VGPR and 124 pts (50.4%) were PriRef. There were no significant differences in the baseline demographics, ISS, R-ISS, or cytogenetic characteristics between ≥VGPR and PriRef. PriRef patients were less likely to have been treated with at least a triplet induction regimen than ≥VGPR (74.2% vs. 89.3%, p <0.01), and they were also less likely to have undergone ASCT (37.1% % vs. 52.5%, p = 0.02). When the two cohorts were stratified by upfront versus delayed ASCT, PriRef pts still demonstrated lower rates of ASCT in both settings, but the differences were not statistically significant (Table 1). There was no significant difference in OS between PriRef and ≥VGPR pts. Median OS for PriRef was 102.9 months compared to 114.9 months in ≥VGPR (p = 0.27) (Figure 1). Out of the 124 PriRef pts, 78 (62.9%) went on to receive subsequent lines of therapy. 39.7% of these PriRef pts received a mAb, such as daratumumab, elotuzumab or isatuximab, in the 2 nd or 3 rd line setting. When stratified by whether they received mAb therapy, median OS of PriRef pts who did not receive a mAb was 86.6 months, whereas median OS was not reached for the PriRef pts who received a mAb (p=0.98) (Figure 2).Conclusions: Our cohort analysis showed that early primary refractoriness to induction in newly diagnosed MM patients was not associated with a lower overall survival, despite lower utilization of triplet regimens and ASCT. Treatment with monoclonal antibodies in the 2 nd and 3 rd line setting may explain this finding. Since the approval of mAbs for myeloma, OS appears to be beneficially impacted. However, the effect of this class of therapy is yet to be fully appreciated in the real-world setting. Therefore, longer follow up data is needed to better assess the true impact of monoclonal antibodies on primary refractory multiple myeloma patients. [Display omitted] DisclosuresNeparidze: GlaxoSmithKline: Research Funding; Janssen: Research Funding; Eidos Therapeutics: Membership on an entity's Board of Directors or advisory committees.

P-029: 1st line combination treatment with proteasome-inhibitor and zoledronic acid is effective in reducing later fractures in multiple myeloma irrespective of MM bone disease

<h3>Introduciton</h3> We examined the medical records of 344 multiple myeloma (MM) patients treated with autologous stem cell transplantation in Oulu University Hospital in 1996-2020. <h3>Methods</h3> Median age of the patients was 61 years and 54.9% were males. ISS was available for 58.4%, R-ISS for 35.9% and IMWG status for 39.4% of the patients. A total of 72.1% had myeloma-associated bone disease and 47.9% had fracture/s at the time of diagnosis. Altogether 58.3% of the patients received proteasome-inhibitor containing treatment at 1st line. Treatment for MM bone disease was given to 90.8% of the patients, 49.4% received zoledronic acid and 29.6% pamindronate. A total of 28.7% of the patients suffered from later fracture. Median follow-up time in this study was 50 months (1-339). <h3>Results</h3> MM bone disease at diagnosis was associated with inferior overall survival (p=0.004) as well as with fracture at diagnosis (p=0.005) irrespective of the type of fracture (pathological vs osteoporotic). The site of the fracture showed statistical significance in that fractures in vertebrae or ribs were associated with better outcome (p=0.028). There were fewer later fractures in patients treated with zoledronic acid although this association did not reach statistical significance (p=0.058). This tendency was clearer in patients with no MM bone disease at diagnosis (p=0.049). The best combination treatment to prevent later fractures was the combination of proteasome-inhibitor and zoledronic acid (p=0.019). <h3>Conclusions</h3> This study suggests that the best treatment option to prevent later fractures might be proteasome-inhibitor combined with zoledronic acid.

Carfilzomib Enhances the Suppressive Effect of Ruxolitinib in Myelofibrosis.

Simple SummaryMyelofibrosis (MF) is a progressive myeloproliferative neoplasm with tendency towards leukemic transformation and has the poorest prognosis amongst the Philadelphia-negative classical myeloproliferative neoplasms (MPN). Ruxolitinib, the first FDA-approved JAK1/2 tyrosine kinase inhibitor, is efficient in reducing spleen size and improving patient symptoms, but it has not been shown to eradicate the MF clone. In this study, using functional genomics techniques, we identified the proteasome family as an additional therapeutic target and demonstrated that inhibition of the proteasome family by carfilzomib in combination with ruxolitinib enhanced suppression of primary MF cells in vitro.As the first FDA-approved tyrosine kinase inhibitor for treatment of patients with myelofibrosis (MF), ruxolitinib improves clinical symptoms but does not lead to eradication of the disease or significant reduction of the mutated allele burden. The resistance of MF clones against the suppressive action of ruxolitinib may be due to intrinsic or extrinsic mechanisms leading to activity of additional pro-survival genes or signalling pathways that function independently of JAK2/STAT5. To identify alternative therapeutic targets, we applied a pooled-shRNA library targeting ~5000 genes to a JAK2V617F-positive cell line under a variety of conditions, including absence or presence of ruxolitinib and in the presence of a bone marrow microenvironment-like culture medium. We identified several proteasomal gene family members as essential to HEL cell survival. The importance of these genes was validated in MF cells using the proteasomal inhibitor carfilzomib, which also enhanced lethality in combination with ruxolitinib. We also showed that proteasome gene expression is reduced by ruxolitinib in MF CD34+ cells and that additional targeting of proteasomal activity by carfilzomib enhances the inhibitory action of ruxolitinib in vitro. Hence, this study suggests a potential role for proteasome inhibitors in combination with ruxolitinib for management of MF patients.

Clonal Evolution in Newly Diagnosed Multiple Myeloma Patients: A Follow-up Study from the Mmrf Commpass Genomics Project

Multiple Myeloma (MM) is an incurable malignancy of bone marrow plasma cells characterized by wide molecular diversity and complex clonal and subclonal architecture. Intra-tumor heterogeneity reflects the evolution of the disease. Clonal structure may affect response to treatment, which, in turn, may shape tumor evolution and, consequently, contribute to drug resistance. Thus, analysis of tumor clonality has profound implications for personalized medicine.Using our recently developed network model of newly diagnosed MM from the MMRF CoMMpass study (Lagana et al, Leukemia 2017) , MMNet, we have identified patterns of gene co-expression significantly associated with tumor clonality and showed that clonality is correlated with mutational burden and relapse.In order to characterize the evolution of clonal structure from diagnosis to relapse, we analyzed Whole-Exome data (WES) from 19 patients enrolled in CoMMpass for whom sequencing data for multiple time points was available. The cohort included both male (12; 63%) and female (7; 37%) patients of white/caucasian (14; 73%) and black/african-american (5; 27%) origin. Patients were distributed among five of the ten classes defined by MMNet: CCND1 (4; 21%), MAF (1; 5%), MMSET (2; 10%), HY/NRAS (4; 21%), and IMM (4; 21%) (4 were unassigned). Also, six patients had the t(11;14) and two had the t(4;14) chromosomal translocations. All patients had received induction therapy, consisting of combinations of proteasome inhibitors (PI) (Bortezomib: 19, 100%; Carfilzomib: 3, 16%), immunomodulatory drugs (IMiDs) (Lenalidomide: 13, 68%; Pomalidomide: 2, 10%; Thalidomide: 1, 5%), steroids (18, 95%) and monoclonal antibodies (Daratumumab: 1, 5%). Best responses to therapy were CR/sCR (3; 16%), VGPR (7; 37%) and PR (9; 47%). Fourteen (68%) patients had SD or PD at the second sequencing time point, with a median PFS of 456 days.Our analysis inferred subclonal tumor composition and evolution based on somatic mutations and copy number alterations (CNA) using PhyloWGS (Deshwar et al, Genome Biol 2015). Patients had one (14; 74%), two (4; 21%) or three (1; 5%) founding clones at baseline, and numerous subclones. Trajectories of cancer cell populations revealed dramatic changes in most patients in terms of clonal and subclonal cell fractions between baseline and relapse. In most patients we observed emergence of new competing clones at relapse, where one or more subclones decreasing in size were replaced by other subclones, indicating selective pressure introduced by therapy (Fig. 1).Subclones were characterized in terms of mutations and CNA and were labeled as stable/resistant or sensitive based on their trajectories from baseline to relapse. Our analysis revealed significant inter-patient heterogeneity in terms of mutations and clonal composition, with few overlaps. We identified subclonal drivers by screening the observed mutations and CNA against a database of known cancer drivers and analysis of co-occurrence and mutual exclusivity. Our analysis revealed that stable/resistant clones were characterized by concurrent deletion of 17p and 13q, and/or mutations in NRAS. In particular, 7 out of 19 patients had at least one mutation in NRAS, observed at baseline in 5 cases, and with two patients carrying two different mutations in two different clones. Our findings support earlier adoption of targeted therapy against RAS (e.g. Trametinib). Other drivers found exclusively in resistant clones included DIS3, FAM46C, ROBO1 and CCND1.Overall, our analysis provides genomics characterization of relapsed patients in CoMMpass following induction therapy, reveals heterogeneous clonal and subclonal composition and trajectories from baseline to relapse, and defines specific somatic mutations (e.g. NRAS) and CNA as drivers of resistance to induction therapy. [Display omitted] DisclosuresMadduri:Foundation Medicine, Inc.: Consultancy. Chari:Janssen: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Millennium Pharmaceuticals, Inc.: Consultancy, Research Funding; Amgen: Honoraria, Research Funding; Celgene Corporation: Consultancy, Research Funding. Cho:Bristol Myers-Squibb: Other: advisory board, Research Funding; Agenus, Inc.: Research Funding; Genentech: Other: advisory board, Research Funding; Ludwig Institute for Cancer Research: Research Funding; Multiple Myeloma Research Foundation: Research Funding. Barlogie:Millenium Pharmaceuticals: Consultancy, Research Funding; Celgene Corporation: Consultancy, Research Funding. Jagannath:Celgene: Consultancy; Bristol-Meyers Squibb: Consultancy; Merck: Consultancy; Medicom: Speakers Bureau; MMRF: Speakers Bureau; Novartis: Consultancy. Dudley:GlaxoSmithKline: Consultancy; Janssen Pharmaceuticals, Inc.: Consultancy; Ayasdi, Inc.: Equity Ownership; Ecoeos, Inc.: Equity Ownership; NuMedii, Inc.: Equity Ownership, Patents & Royalties; Ontomics, Inc.: Equity Ownership; Personalis: Patents & Royalties; AstraZeneca: Consultancy.

Real-world comparative effectiveness of triplets containing bortezomib (B), carfilzomib (C), daratumumab (D), or ixazomib (I) in relapsed/refractory multiple myeloma (RRMM) in the US

Multiple available combinations of proteasome inhibitors, immunomodulators (IMIDs), and monoclonal antibodies are shifting the relapsed/refractory multiple myeloma (RRMM) treatment landscape. Lack of head-to-head trials of triplet regimens highlights the need for real-world (RW) evidence. We conducted an RW comparative effectiveness analysis of bortezomib (V), carfilzomib (K), ixazomib (I), and daratumumab (D) combined with either lenalidomide or pomalidomide plus dexamethasone (Rd or Pd) in RRMM. A retrospective cohort of patients initiating triplet regimens in line of therapy (LOT) ≥ 2 on/after 1/1/2014 was followed between 1/2007 and 3/2018 in Optum’s deidentified US electronic health records database. Time to next treatment (TTNT) was estimated using Kaplan-Meier methods; regimens were compared using covariate-adjusted Cox proportional hazard models. Seven hundred forty-one patients (820 patient LOTs) with an Rd backbone (VRd, n = 349; KRd, n = 218; DRd, n = 99; IRd, n = 154) and 348 patients (392 patient LOTs) with a Pd backbone (VPd, n = 52; KPd, n = 146; DPd, n = 149; IPd, n = 45) in LOTs ≥2 were identified. More patients ≥75 years received IRd (39.6%), IPd (37.8%), and VRd (36.7%) than other triplets. More patients receiving VRd/VPd were in LOT2 vs other triplets. Unadjusted median TTNT in LOT ≥ 2: VRd, 13.9; KRd, 8.7; IRd, 11.4; DRd, not estimable (NE); and VPd, 12.0; KPd, 6.7; IPd, 9.5 months; DPd, NE. In covariate-adjusted analysis, only KRd vs DRd was associated with a significantly higher risk of next LOT initiation/death (HR 1.72; P = 0.0142); no Pd triplet was significantly different vs DPd in LOT ≥ 2. Our data highlight important efficacy/effectiveness gaps between results observed in phase 3 clinical trials and those realized in the RW.

A Proteasome Mutation Sensitizes P.falciparum Cam3.II K13C580Y Parasites to DHA and OZ439.

Artemisinin-based combination therapies (ACTs), the World Health Organization-recommended first-line therapy for uncomplicated falciparum malaria, has led to significant decreases in malaria-associated morbidity and mortality in the past two decades. Decreased therapeutic efficacy of artemisinins, the cornerstone of ACTs, is threatening the gains made against this disease. As such, novel therapeutics with uncompromised mechanisms of action are needed to combat parasite-mediated antimalarial resistance. We have previously reported the antimalarial activity of Plasmodium falciparum-specific proteasome inhibitors in conjunction with a variety of antimalarials in clinical use or in preclinical investigations and of proteasome mutants generated in response to these inhibitors. Here, we discover that despite harboring K13C580Y, which has conventionally mediated artemisinin resistance in vitro as measured by increased survival in ring-stage survival assays (RSA), the Cam3.II strain parasites of Cambodian origin that have acquired an additional mutation in the proteasome display increased susceptibility to DHA and OZ439. This discovery implicates the proteasome in peroxide susceptibilities and has favorable implications on the use of peroxide and proteasome inhibitor combination therapy for the treatment of artemisinin-resistant malaria.

Generation of TRAIL-resistant cell line models reveals distinct adaptive mechanisms for acquired resistance and re-sensitization.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces tumor cell-specific apoptosis, making it a prime therapeutic candidate. However, many tumor cells are either innately TRAIL-resistant, or they acquire resistance with adaptive mechanisms that remain poorly understood. In this study, we generated acquired TRAIL resistance models using multiple glioblastoma (GBM) cell lines to assess the molecular alterations in the TRAIL-resistant state. We selected TRAIL-resistant cells through chronic and long-term TRAIL exposure and noted that they showed persistent resistance both in vitro and in vivo. Among known TRAIL-sensitizers, proteosome inhibitor Bortezomib, but not HDAC inhibitor MS-275, was effective in overcoming resistance in all cell models. This was partly achieved through upregulating death receptors and pro-apoptotic proteins, and downregulating major anti-apoptotic members, Bcl-2 and Bcl-xL. We showed that CRISPR/Cas9 mediated silencing of DR5 could block Bortezomib-mediated re-sensitization, demonstrating its critical role. While overexpression of Bcl-2 or Bcl-xL was sufficient to confer resistance to TRAIL-sensitive cells, it failed to override Bortezomib-mediated re-sensitization. With RNA sequencing in multiple paired TRAIL-sensitive and TRAIL-resistant cells, we identified major alterations in inflammatory signaling, particularly in the NF-κB pathway. Inhibiting NF-κB substantially sensitized the most resistant cells to TRAIL, however, the sensitization effect was not as great as what was observed with Bortezomib. Together, our findings provide new models of acquired TRAIL resistance, which will provide essential tools to gain further insight into the heterogeneous therapy responses within GBM tumors. Additionally, these findings emphasize the critical importance of combining proteasome inhibitors and pro-apoptotic ligands to overcome acquired resistance.