Is re-challenge still an option as salvage therapy in multiple myeloma? The case of REal-life BOrtezomib re-Use as secoND treatment for relapsed patients exposed frontline to bortezomib-based therapies (the REBOUND Study).

Therapeutic re-challenge is currently a debated issue in the field of multiple myeloma (MM), given the recent availability of several new drugs and combinations. However, very few specific evidences are available about bortezomib re-use at first relapse. This multicenter, observational, retrospective study enrolled 134 MM patients with significant response after bortezomib-based frontline regimens and who had received a first salvage treatment containing bortezomib at relapse. The overall response rate was 71%, including 40% partial responses, 24% very good partial responses, and 7% complete responses. Re-treatment was well-tolerated, with no significant new or unexpected toxicities observed. The median duration of second progression-free survival (PFS) was 15 months, while median PFS2 was 55 months. With a median follow-up of 56 months, overall survival was 94 months for the entire series, without significant differences between patients undergoing or not undergoing transplant procedures. This real-life survey indicates that re-treatment including bortezomib as a first salvage therapy could be still considered in MM patients achieving durable response after initial exposure to bortezomib.

Immuno-oncologic Approaches: CAR-T Cells and Checkpoint Inhibitors.

Advances in understanding myeloma biology have shown that disease progression is not only the consequence of intrinsic tumor changes but also of interactions between the tumor and the microenvironment in which the cancer grows. The immune system is an important component of the tumor microenvironment in myeloma, and acting on the immune system is an appealing new treatment strategy. There are 2 ways to act toward immune cells and boost antitumor immunity: (1) to increase antitumor activity (acting on T and NK cytotoxic cells), and (2) to reduce immunosuppression (acting on myeloid-derived stem cells and T regulatory cells). Checkpoint inhibitors and adoptive cell therapy (ACT) are 2 of the main actors, together with monoclonal antibodies and immunomodulatory agents, in the immune-oncologic approach. The aim of checkpoint inhibitors is to release the brakes that block the action of the immune system against the tumor. Anti-programmed death-1 (PD-1) and PD-1-Ligand, as well as anti-CTLA4 and KIR are currently under evaluation, as single agents or in combination, with the best results achieved so far with combination of anti-PD-1 and immunomodulatory agents. The aim of ACT is to create an immune effector specific against the tumor. Preliminary results on chimeric antigen receptor (CAR) T cells, first against CD19, and more recently against B-cell maturation antigen, have shown to induce durable responses in heavily pretreated patients. This review focuses on the most recent clinical results available on the use of checkpoint inhibitors and CAR-T cells in myeloma, in the context of the new immune-oncologic approach.

Minimal residual disease after transplantation or lenalidomide-based consolidation in myeloma patients: a prospective analysis.

We analyzed 50 patients who achieved at least a very good partial response in the RV-MM-EMN-441 study. Patients received consolidation with autologous stem-cell transplantation (ASCT) or cyclophosphamide-lenalidomide-dexamethasone (CRD), followed by Lenalidomide-based maintenance. We assessed minimal residual disease (MRD) by multi-parameter flow cytometry (MFC) and allelic-specific oligonucleotide real-time quantitative polymerase chain reaction (ASO-RQ-PCR) after consolidation, after 3 and 6 courses of maintenance, and thereafter every 6 months until progression. By MFC analysis, 19/50 patients achieved complete response (CR) after consolidation, and 7 additional patients during maintenance. A molecular marker was identified in 25/50 patients, 4/25 achieved molecular-CR after consolidation, and 3 additional patients during maintenance. A lower MRD value by MFC was found in ASCT patients compared with CRD patients (p=0.0134). Tumor burden reduction was different in patients with high-risk vs standard-risk cytogenetics (3.4 vs 5.2, ln-MFC; 3 vs 6 ln-PCR, respectively) and in patients who relapsed vs those who did not (4 vs 5, ln-MFC; 4.4 vs 7.8 ln-PCR). MRD progression anticipated clinical relapse by a median of 9 months while biochemical relapse by a median of 4 months. MRD allows the identification of a low-risk group, independently of response, and a better characterization of the activity of treatments.

Autologous transplantation and maintenance therapy in multiple myeloma.

BACKGROUND: This open-label, randomized, phase 3 study compared melphalan at a dose of 200 mg per square meter of body-surface area plus autologous stem-cell transplantation with melphalan-prednisone-lenalidomide (MPR) and compared lenalidomide maintenance therapy with no maintenance therapy in patients with newly diagnosed multiple myeloma. METHODS: We randomly assigned 273 patients 65 years of age or younger to high-dose melphalan plus stem-cell transplantation or MPR consolidation therapy after induction, and 251 patients to lenalidomide maintenance therapy or no maintenance therapy. The primary end point was progression-free survival. RESULTS: The median follow-up period was 51.2 months. Both progression-free and overall survival were significantly longer with high-dose melphalan plus stem-cell transplantation than with MPR (median progression-free survival, 43.0 months vs. 22.4 months; hazard ratio for progression or death, 0.44; 95% confidence interval [CI], 0.32 to 0.61; P<0.001; and 4-year overall survival, 81.6% vs. 65.3%; hazard ratio for death, 0.55; 95% CI, 0.32 to 0.93; P=0.02). Median progression-free survival was significantly longer with lenalidomide maintenance than with no maintenance (41.9 months vs. 21.6 months; hazard ratio for progression or death, 0.47; 95% CI, 0.33 to 0.65; P<0.001), but 3-year overall survival was not significantly prolonged (88.0% vs. 79.2%; hazard ratio for death, 0.64; 95% CI, 0.36 to 1.15; P=0.14). Grade 3 or 4 neutropenia was significantly more frequent with high-dose melphalan than with MPR (94.3% vs. 51.5%), as were gastrointestinal adverse events (18.4% vs. 0%) and infections (16.3% vs. 0.8%); neutropenia and dermatologic toxic effects were more frequent with lenalidomide maintenance than with no maintenance (23.3% vs. 0% and 4.3% vs. 0%, respectively). CONCLUSIONS: Consolidation therapy with high-dose melphalan plus stem-cell transplantation, as compared with MPR, significantly prolonged progression-free and overall survival among patients with multiple myeloma who were 65 years of age or younger. Lenalidomide maintenance, as compared with no maintenance, significantly prolonged progression-free survival. (Funded by Celgene; ClinicalTrials.gov number, NCT00551928.).

Pharmacophore modeling technique applied for the discovery of proteasome inhibitors.

INTRODUCTION: The 26S proteasome has many important roles in the biological functions of the cells, and proteasome inhibitors have multiple and complex activities on cells. These compounds can be natural or synthesized. Most synthetic derivatives have been rationally designed, synthesized and optimized to obtain the best selectivity and increase the activity. The design of chemical entities with desired molecular identification, which plays an important role in biological systems, is provided by pharmacophore modeling. Indeed, pharmacophore models can be established either in a ligand-based manner or in a receptor-based manner. AREAS COVERED: The authors discuss the application of pharmacophore modeling techniques to proteasome inhibitors development. Furthermore, the article reviews the classification of the currently discovered proteasome inhibitors where the principal mechanism of action and clinical application are represented. EXPERT OPINION: In the era of new drug development, database of compounds should be thoroughly evaluated with a combination of methods that consider both pharmacophore- and ligand-based virtual screening. The concept of pharmacophore helps to discover new active compounds and to evaluate their activity. The nature of proteasome inhibitor pharmacophore affects the secondary active-site specificity; indeed, increasing specificity decreases the cytotoxicity of the proteasome inhibitors. It is hypothesized that the balanced simultaneous modulation of a few druggable targets may have superior efficacy and fewer side effects than single-target or combination therapies for the treatment of human cancers. The discovery of new compounds should aim to find more active compounds that improve the compliance of patients.

Carfilzomib, cyclophosphamide, and dexamethasone in patients with newly diagnosed multiple myeloma: a multicenter, phase 2 study.

This multicenter, open-label phase 2 trial determined the safety and efficacy of carfilzomib, a novel and irreversible proteasome inhibitor, in combination with cyclophosphamide and dexamethasone (CCyd) in patients with newly diagnosed multiple myeloma (NDMM) ≥65 years of age or who were ineligible for autologous stem cell transplantation. Patients (N = 58) received CCyd for up to 9 28-day cycles, followed by maintenance with carfilzomib until progression or intolerance. After a median of 9 CCyd induction cycles (range 1-9), 95% of patients achieved at least a partial response, 71% achieved at least a very good partial response, 49% achieved at least a near complete response, and 20% achieved stringent complete response. After a median follow-up of 18 months, the 2-year progression-free survival and overall survival rates were 76% and 87%, respectively. The most frequent grade 3 to 5 toxicities were neutropenia (20%), anemia (11%), and cardiopulmonary adverse events (7%). Peripheral neuropathy was limited to grades 1 and 2 (9%). Fourteen percent of patients discontinued treatment because of adverse events, and 21% of patients required carfilzomib dose reductions. In summary, results showed high complete response rates and a good safety profile. This trial was registered at clinicaltrials.gov as #NCT01346787.

Complete response correlates with long-term progression-free and overall survival in elderly myeloma treated with novel agents: analysis of 1175 patients.

Complete response (CR) was an uncommon event in elderly myeloma patients until novel agents were combined with standard oral melphalan-prednisone. This analysis assesses the impact of treatment response on progression-free survival (PFS) and overall survival (OS). We retrospectively analyzed 1175 newly diagnosed myeloma patients, enrolled in 3 multicenter trials, treated with melphalan-prednisone alone (n = 332), melphalan-prednisone-thalidomide (n = 332), melphalan-prednisone-bortezomib (n = 257), or melphalan-prednisone-bortezomib-thalidomide (n = 254). After a median follow-up of 29 months, the 3-year PFS and OS were 67% and 27% (hazard ratio = 0.16; P < .001), and 91% and 70% (hazard ratio = 0.15; P < .001) in patients who obtained CR and in those who achieved very good partial response, respectively. Similar results were observed in patients older than 75 years. Multivariate analysis confirmed that the achievement of CR was an independent predictor of longer PFS and OS, regardless of age, International Staging System stage, and treatment. These findings highlight a significant association between the achievement of CR and long-term outcome, and support the use of novel agents to achieve maximal response in elderly patients, including those more than 75 years. This trial was registered at www.clinicaltrials.gov as #NCT00232934, #ISRCTN 90692740, and #NCT01063179.

Efficacy and safety of once-weekly bortezomib in multiple myeloma patients.

In a recent phase 3 trial, bortezomib-melphalan-prednisone-thalidomide followed by maintenance treatment with bortezomib-thalidomide demonstrated superior efficacy compared with bortezomib-melphalan-prednisone. To decrease neurologic toxicities, the protocol was amended and patients in both arms received once-weekly instead of the initial twice-weekly bortezomib infusions: 372 patients received once-weekly and 139 twice-weekly bortezomib. In this post-hoc analysis we assessed the impact of the schedule change on clinical outcomes and safety. Long-term outcomes appeared similar: 3-year progression-free survival rate was 50% in the once-weekly and 47% in the twice-weekly group (P > .999), and 3-year overall survival rate was 88% and 89%, respectively (P = .54). The complete response rate was 30% in the once-weekly and 35% in the twice-weekly group (P = .27). Nonhematologic grade 3/4 adverse events were reported in 35% of once-weekly patients and 51% of twice-weekly patients (P = .003). The incidence of grade 3/4 peripheral neuropathy was 8% in the once-weekly and 28% in the twice-weekly group (P < .001); 5% of patients in the once-weekly and 15% in the twice-weekly group discontinued therapy because of peripheral neuropathy (P < .001). This improvement in safety did not appear to affect efficacy. This study is registered at http://www.clinicaltrials.gov as NCT01063179.

Melphalan, prednisone, thalidomide and defibrotide in relapsed/refractory multiple myeloma: results of a multicenter phase I/II trial.

BACKGROUND: Defibrotide is a novel orally bioavailable polydisperse oligonucleotide with anti-thrombotic and anti-adhesive effects. In SCID/NOD mice, defibrotide showed activity in human myeloma xenografts. This phase I/II study was conducted to identify the most appropriate dose of defibrotide in combination with melphalan, prednisone and thalidomide in patients with relapsed and relapsed/refractory multiple myeloma, and to determine its safety and tolerability as part of this regimen. DESIGN AND METHODS: This was a phase I/II, multicenter, dose-escalating, non-comparative, open label study. Oral melphalan was administered at a dose of 0.25 mg/kg on days 1-4, prednisone at a dose of 1.5 mg/kg also on days 1-4 and thalidomide at a dose of 50-100 mg/day continuously. Defibrotide was administered orally at three dose-levels: 2.4, 4.8 or 7.2 g on days 1-4 and 1.6, 3.2, or 4.8 g on days 5-35. RESULTS: Twenty-four patients with relapsed/refractory multiple myeloma were enrolled. No dose-limiting toxicity was observed. In all patients, the complete response plus very good partial response rate was 9%, and the partial response rate was 43%. The 1-year progression-free survival and 1-year overall survival rates were 34% and 90%, respectively. The most frequent grade 3-4 adverse events included neutropenia, thrombocytopenia, anemia and fatigue. Deep vein thrombosis was reported in only one patient. CONCLUSIONS: This combination of melphalan, prednisone and thalidomide together with defibrotide showed anti-tumor activity with a favorable tolerability. The maximum tolerated dose of defibrotide was identified as 7.2 g p.o. on days 1-4 followed by 4.8 g p.o. on days 5-35. Further trials are needed to confirm the role of this regimen and to evaluate the combination of defibrotide with new drugs.

Efficacy of a combination of human recombinant erythropoietin + 13-cis-retinoic acid and dihydroxylated vitamin D3 to improve moderate to severe anaemia in low/intermediate risk myelodysplastic syndromes.

The efficacy of human recombinant erythropoietin (rEPO) in myelodysplastic syndromes (MDS) has generally been best in untransfused patients with 'refractory anaemia' according to the World Health Organization (WHO). We treated 63 MDS patients [excluding refractory anaemia with excess blasts, type 2 (RAEB2)] with a previously tested combination of 13-cis-retinoic acid and dihydroxylated vitamin D3 +/- 6-thioguanine in addition to rEPO. Most patients were categorized as refractory cytopenia with multilineage dysplasia and RAEB1, with intermediate 1 International Prognostic Scoring System (IPSS) score; all had Hb <95 g/l, and 70% required regular erythrocyte transfusions. Treatment was well tolerated, and erythroid response rate according to new International Working Group criteria was 60%: 50% in RAEB1 and 64% in non-RAEB patients (P = 0.383). Response rate was not affected by transfusion requirement (63%; 58% in untransfused), IPSS and WHO Prognostic Scoring System scores, and weekly rEPO dosage (30-50 000 U vs. 80 000 U). Median response duration was 16 months. Median survival reached 14 months for RAEB1 and 55 months for non-RAEB patients, with a significant difference in the latter between responders and non-responders (median 82 months vs. 44 months; P = 0.036). Our combined therapy, independent of rEPO dosage, achieved in patients with unfavourable response predictors, a rate of anaemia improvement comparable to the best obtained in lower risk patients by high-dose rEPO.