Proteasome inhibitors have revolutionized outcomes in multiple myeloma, but they are used empirically, and primary and secondary resistance are emerging problems. We have identified TJP1 as a ...determinant of plasma cell proteasome inhibitor susceptibility. TJP1 suppressed expression of the catalytically active immunoproteasome subunits LMP7 and LMP2, decreased proteasome activity, and enhanced proteasome inhibitor sensitivity in vitro and in vivo. This occurred through TJP1-mediated suppression of EGFR/JAK1/STAT3 signaling, which modulated LMP7 and LMP2 levels. In the clinic, high TJP1 expression in patient myeloma cells was associated with a significantly higher likelihood of responding to bortezomib and a longer response duration, supporting the use of TJP1 as a biomarker to identify patients most likely to benefit from proteasome inhibitors.
•TJP1 expression is a biomarker of proteasome inhibitor sensitivity in myeloma•Signaling through the TJP1/EGFR/JAK/STAT pathway influences proteasome capacity•EGFR/JAK/STAT suppression induces chemosensitization to proteasome inhibitors
Zhang et al. show that TJP1 enhances multiple myeloma sensitivity to proteasome inhibitors by reducing the expression of the immunoproteasome subunits LMP7 and LMP2 via suppression of EGFR/JAK1/STAT3 signaling, and that high TJP1 expression in patient myeloma cells correlates with better response to bortezomib.
Panobinostat is an oral pan-deacetylase inhibitor that synergizes with bortezomib to inhibit both the aggresome and proteasome pathways in preclinical studies. PANORAMA 2 is a phase 2 trial of ...panobinostat in combination with bortezomib and dexamethasone to treat patients with relapsed and bortezomib-refractory multiple myeloma (with ≥2 prior lines of therapy, including an immunomodulatory drug, and patients who had progressed on or within 60 days of the last bortezomib-based therapy). Fifty-five heavily pretreated patients were enrolled (median, 4 prior regimens, including a median of 2 prior bortezomib-containing regimens). The overall response rate was 34.5% (1 near-complete response and 18 partial responses). An additional 10 patients achieved minimal response, for a clinical benefit rate of 52.7%. Median exposure and progression-free survival were 4.6 and 5.4 months, respectively. In patients who achieved a response, median time to response was 1.4 months, and median duration of response was 6.0 months. Common grade 3/4 adverse events, regardless of study drug relationship, included thrombocytopenia (63.6%), fatigue (20.0%), and diarrhea (20.0%). Only 1 patient had grade 3 peripheral neuropathy. Panobinostat, when combined with bortezomib and dexamethasone, can recapture responses in heavily pretreated, bortezomib-refractory multiple myeloma patients. This trial was registered at www.clinicaltrials.gov as #NCT01083602.
•Panobinostat + bortezomib + dexamethasone recaptures responses in heavily pretreated, bortezomib-refractory multiple myeloma patients.
Hedgehog (Hh) signaling plays an important role in the oncogenesis of B-cell malignancies such as multiple myeloma (MM). However, the source of Hh ligand sonic hedgehog (SHH) and its target cells ...remains controversial. Previous studies showed that stromally induced Hh signaling is essential for the tumor cells and that CD19+CD138– MM stem cells are the target cells of Hh signaling. Here we demonstrate that SHH was mainly secreted by human myeloma cells but not by stromal cells in MM bone marrow. Autocrine SHH enhanced CD138+ myeloma cell proliferation and protected myeloma cells from spontaneous and stress-induced apoptosis. More importantly, autocrine SHH protected myeloma cells against chemotherapy-induced apoptosis in vitro and in vivo. Combinational treatment with chemotherapy and SHH-neutralizing antibody displayed synergistic antimyeloma effects. Mechanistic studies showed that SHH signaling activated the SHH/GLI1/BCL-2 axis, leading to the inhibition of myeloma cell apoptosis. Thus, this study identifies the myeloma autocrine Hh signaling pathway as a potential target for the treatment of MM. Targeting this pathway may improve the efficacy of chemotherapy in MM patients.
•CD138+ MM cells are a major source of SHH.•Autocrine SHH enhances MM drug resistance.
Proteasome inhibition with bortezomib is a validated approach to the treatment of multiple myeloma, but drug resistance often emerges and limits its utility in the retreatment setting. To begin to ...identify some of the mechanisms involved, we developed bortezomib-resistant myeloma cell lines that, unlike previously reported models, showed no β5 subunit mutations. Instead, up-regulation of the insulin-like growth factor (IGF)–1 axis was identified, with increased autocrine and paracrine secretion of IGF-1, leading to increased activation of the IGF-1 receptor (IGF-1R). Exogenous IGF-1 reduced cellular sensitivity to bortezomib, whereas pharmacologic or small hairpin RNA–mediated IGF-1R suppression enhanced bortezomib sensitivity in cell lines and patient samples. In vitro studies with OSI-906, a clinically relevant dual IGF-1R and insulin receptor inhibitor, showed it acted synergistically with bortezomib, and potently resensitized bortezomib-resistant cell lines and patient samples to bor-tezomib. Importantly, OSI-906 in combination with bortezomib also overcame bor-tezomib resistance in an in vivo model of myeloma. Taken together, these data support the hypothesis that signaling through the IGF-1/IGF-1R axis contributes to acquired bortezomib resistance, and provide a rationale for combining bortezomib with IGF-1R inhibitors like OSI-906 to overcome or possibly prevent the emergence of bortezomib-refractory disease in the clinic.
Lenalidomide, an oral immunomodulatory drug that is similar to thalidomide but has a different safety profile, has clinical activity in relapsed or refractory multiple myeloma.
Patients in the United ...States and Canada who had received at least one previous therapy for multiple myeloma but who required additional treatment were randomly assigned to receive either 25 mg of lenalidomide or placebo on days 1 to 21 of a 28-day cycle. Both groups also received 40 mg of oral dexamethasone on days 1 to 4, 9 to 12, and 17 to 20 for the first four cycles. After the fourth cycle, 40 mg of dexamethasone was administered only on days 1 to 4. Safety, clinical response, time to progression, and overall survival were assessed.
We assigned 177 patients to the lenalidomide group and 176 to the placebo group. Complete, near-complete, or partial responses occurred in 108 patients (61.0%) in the lenalidomide group and in 35 patients (19.9%) in the placebo group (P<0.001); complete responses occurred in 14.1% and 0.6%, respectively (P<0.001). The median time to progression was 11.1 months in the lenalidomide group and 4.7 months in the placebo group (P<0.001). Median overall survival times in the two groups were 29.6 months and 20.2 months, respectively (P<0.001). Grade 3 or 4 adverse events were reported in 85.3% of the lenalidomide group and in 73.1% of the placebo group; these events resulted in study discontinuation in 19.8% and 10.2%, respectively. Grade 3 or 4 neutropenia and venous thromboembolism were more common in the lenalidomide group than in the placebo group (41.2% vs. 4.6% and 14.7% vs. 3.4%, respectively; P<0.001 for both comparisons).
Lenalidomide plus dexamethasone is superior to placebo plus dexamethasone in patients with relapsed or refractory multiple myeloma. (ClinicalTrials.gov number, NCT00056160 ClinicalTrials.gov.).
Waldenström macroglobulinemia (WM) is a distinct type of indolent lymphoplasmacytic lymphoma (LPL) with a high frequency of MYD88L265P mutation. Treatment for WM/LPL is highly variable in clinic and ...ibrutinib (a Bruton tyrosine kinase inhibitor, BTKi) has become a new treatment option for WM. To investigate the clinical impact of genetic alterations in WM, we assembled a large cohort of 219 WMs and 12 LPLs dividing into two subcohorts: a training cohort, patients sequenced by a same targeted 29-gene next-generation sequencing (NGS) panel, and a validation cohort, patients sequenced by allele specific-PCR or other targeted NGS panels. In both training and validation subcohorts, MYD88L265P and TP53 mutations showed favorable and adverse prognostic effects, respectively. CXCR4 nonsense/missense mutations (CXCR4NS/MS), cytogenetic complex karyotypes, and a family history of lymphoma/leukemia in first-degree relatives were associated with significantly worse clinical outcomes only or more in the validation subcohort. We further investigated the efficacy of various treatments and interaction with genetic factors in the entire cohort. Upfront dexamethasone usage was associated with poorer clinical outcomes in patients who received non-proteasome-containing chemotherapy as first-line treatment independent of genetic factors. Maintenance rituximab was associated with better survival. Ibrutinib/BTKi showed potential benefit in relapsed/refractory patients and patients without CXCR4NS/MS including those with TP53 mutations. In conclusion, genetic testing for MYD88L265P, TP53, and CXCR4 mutations and cytogenetic analysis provide important information for prognosis prediction and therapy selection. The findings in these study are valuable for improving treatment decisions on therapies available for WM/LPL patients with integration of NGS in clinic.
In a retrospective pooled analysis of 11 clinical trials of lenalidomide-based therapy for relapsed/refractory multiple myeloma (MM; N = 3846), the overall incidence rate (IR, events per 100 ...patient-years) of second primary malignancies (SPMs) was 3.62. IR of invasive (hematologic and solid tumor) SPMs was 2.08, consistent with the background incidence of developing cancer. In a separate analysis of pooled data from pivotal phase 3 trials of relapsed or refractory MM (N = 703), the overall IR of SPMs was 3.98 (95% confidence interval CI, 2.51-6.31) with lenalidomide/dexamethasone and 1.38 (95% CI, 0.44-4.27) with placebo/dexamethasone; IRs of nonmelanoma skin cancers were 2.40 (95% CI, 1.33-4.33) and 0.91 (95% CI, 0.23-3.66), respectively; IRs of invasive SPMs were 1.71 (95% CI, 0.86-3.43) and 0.91 (95% CI, 0.23-3.66), respectively. The risk of SPMs must be taken into account before initiating lenalidomide treatment. In the context of the observed survival benefit in relapsed or refractory MM patients, the benefit/risk profile of lenalidomide/dexamethasone remains positive.
In this study, the addition of ixazomib to lenalidomide maintenance post-autologous stem cell transplant (ASCT) in 64 patients with newly diagnosed multiple myeloma was evaluated on the basis of the ...observed benefit of lenalidomide-only maintenance in prior studies.
Patients were started on maintenance therapy with lenalidomide and ixazomib within 60-180 days of stem cell infusion.
Response rates deepened over time from baseline post-ASCT for 39 patients. The complete response (CR)/stringent CR rate was 43% and median overall survival was not reached with a median follow-up of 62 months (range, 25-82 months). Median PFS (mPFS) for all patients was 73 months and has not been reached for those with International Staging System (ISS) stage 1 disease. mPFS in 9 patients who had ISS stage 3 disease and 14 patients who had high-risk cytogenetics was 34 and 25 months, respectively. Twenty-two patients had progressive disease, while 19 patients continue to receive dual maintenance. The most common grade 3/4 adverse events included neutropenia, leukopenia, thrombocytopenia, lung infections, diarrhea, and maculopapular rash. Second primary malignancies occurred in 9 patients. Toxicity led to dose reductions in ixazomib and lenalidomide in 20 and 31 patients, respectively. Discontinuation of ixazomib due to toxicity occurred in 4 patients. Grade 1/2 neuropathy occurred in 22 patients and led to reduction or discontinuation of ixazomib in 2 patients.
The addition of ixazomib to lenalidomide maintenance demonstrated a better than expected PFS compared with historical data using lenalidomide alone and was safe and tolerable.
Background
The prognostic significance of minimal residual disease (MRD) status before autologous hematopoietic stem cell transplantation (autoHCT) in patients with multiple myeloma (MM) has not been ...clearly elucidated.
Methods
Retrospective single‐center study of adult MM patients who achieved ≥very good partial response (VGPR) after induction therapy from 2015 to 2021 received upfront autoHCT and had available pretransplant MRD status by next‐generation flow cytometry. The cohort was divided into pretransplant MRD‐negative (MRDneg) and MRD‐positive (MRDpos) groups.
Results
A total of 733 patients were included in our analysis; 425 were MRDneg and 308 MRDpos at autoHCT. In the MRDpos group, more patients had high‐risk cytogenetic abnormalities (48% vs. 38%, respectively; p = .025), whereas fewer patients achieved ≥CR before autoHCT (14% vs. 40%; p < .001). At day 100 after autoHCT, 37% of the MRDpos versus 71% of the MRDneg achieved ≥CR, and at best posttransplant response 65% versus 88% achieved ≥CR, respectively. After a median follow‐up of 27.6 months (range, 0.7–82.3), the median PFS was significantly shorter for patients in the MRDpos group compared to the MRDneg group: 48.2 months (95% confidence interval CI, 0.3–80.5) versus 80.1 months (95% CI, 0.5–80.1), respectively (p < .001). There was no significant difference in overall survival between the two groups (p = .41). Pretransplant MRDpos status was predictive of shorter PFS in multivariate analysis (hazard ratio, 1.80; 95% CI, 1.31–2.46; p < .001). The impact of pretransplant MRD status was retained in most of the examined subgroups.
Conclusions
In patients achieving ≥VGPR to induction, pretransplant MRDpos status was associated with a lower CR rate after autoHCT and a shorter PFS.
This retrospective single‐center study evaluated the prognostic impact of pretransplant minimal residual disease (MRD) status by next‐generation flow cytometry in 733 multiple myeloma patients who achieved ≥ very good partial response after induction therapy and received upfront autologous hematopoietic stem cell transplantation (autoHCT). Pretransplant MRD positivity was associated with a lower complete remission rate after autoHCT and a shorter progression‐free survival.
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