Esther Masih-Khan

Influence of cytogenetics in patients with relapsed or refractory multiple myeloma treated with lenalidomide plus dexamethasone: adverse effect of deletion 17p13

Although the combination of lenalidomide and dexamethasone is effective therapy for patients with relapsed/refractory multiple myeloma, the influence of high-risk cytogenetic abnormalities on outcomes is unknown. This subanalysis of a large, open-label study investigated the effects of the most common unfavorable cytogenetic abnormalities detected by fluorescence in situ hybridization, del(13q), t(4;14), and del(17p13), in 130 evaluable patients treated with this regimen. Whereas patients with either del(13q) or t(4;14) experienced a median time to progression and overall survival comparable with those without these cytogenetic abnormalities, patients with del(17p13) had a significantly worse outcome, with a median time to progression of 2.22 months (hazard ratio, 2.82; P < .001) and median overall survival of 4.67 months (hazard ratio, 3.23; P < .001). Improved therapeutic strategies are required for this subgroup of patients. This study was registered at www.ClinicalTrials.gov as #NCT00179647.

Preclinical studies of fibroblast growth factor receptor 3 as a therapeutic target in multiple myeloma

Dysregulation of fibroblast growth factor receptor 3 (FGFR3) by the translocation t(4;14)(p16;q32) occurs in 15% of multiple myeloma (MM) patients and confers a growth and survival advantage to malignant plasma cells. As FGFR3 is a molecular target, we assessed the therapeutic potential of the FGFR‐specific tyrosine kinase inhibitors SU5402 and SU10991 in MM. SU5402 inhibited FGFR3 phosphorylation in vitro and in murine MM tumour models. B cells dependent on FGFR3 for survival were specifically sensitive to SU5402. A panel of 11 human myeloma cell lines was studied, five bearing the t(4;14) translocation. The KMS11 human myeloma cell line, which expresses constitutively active mutant FGFR3, displayed an 85% decrease in S‐phase cells, a 95% increase in G0/G1 cells, and 4·5‐fold increase in apoptotic cells after 72 h treatment with 10 μmol/l SU5402. Activated extracellular signal‐regulated kinases 1 and 2 and signal transducer and activator of transcription 3 were rapidly down‐regulated after SU5402 treatment. In human myeloma cell lines expressing wild‐type FGFR3 the stimulating effect of aFGF ligand was abrogated by SU5402 treatment. Myeloma cells lacking the t(4;14) or with the t(4;14) and a secondary RAS mutation did not respond to therapy. These findings support the development of clinical trials of early intervention with FGFR3 inhibitors in t(4;14) myeloma.

Second Autologous Stem Cell Transplantation as Salvage Therapy for Multiple Myeloma: Impact on Progression-Free and Overall Survival

The role of a second autologous stem cell transplant (ASCT) as salvage therapy is unclear, particularly with the availability of novel agents to treat progressive multiple myeloma (MM). We retrospectively reviewed all MM patients who received a second ASCT as salvage therapy at our center from March 1992 to December 2009. Eighty-one MM patients received a second ASCT for relapsed MM. The median time to relapse after first transplant was 39 months (9.83-100). All patients received reinduction therapy before the second ASCT. The high-dose regimen given before the second ASCT consisted of melphalan (MEL) alone in the majority. Complete response, very good partial response, and partial response were seen in 7.7%, 39.7%, and 50%, respectively, at day 100 post-ASCT; the median time to relapse after the second ASCT was 19 months. Early deaths occurred in 2.6%. Median progression-free survival (PFS) based on the time to myeloma relapse after first ASCT was 9.83 months (relapse ≤ 24 months) and 17.3 months (relapse ≥ 24 months) (P < .05). Median overall survival (OS) was 28.47 months (relapse ≤ 24 months) and 71.3 months (relapse >24 months) (P = .006). Second ASCT is a feasible and safe option for salvage therapy in MM. The best outcome was observed in patients whose time to progression was >24 months after first ASCT, as these patients had a subsequent PFS lasting over 1 year and an OS of almost 6 years.

Central nervous system involvement with multiple myeloma: long term survival can be achieved with radiation, intrathecal chemotherapy, and immunomodulatory agents

Involvement of the central nervous system (CNS) in multiple myeloma (MM) is a rare complication, with reported survival of <6 months. This report describes 37 MM patients with leptomeningeal and/or parenchymal brain involvement treated at our institution and identifies factors associated with long‐term survival. From January 1999 to December 2010, 37 patients with CNS MM were evaluated at our institution. Clinical characteristics, treatment and survival were retrospectively collected. CNS disease was present at MM diagnosis in 24% and at relapse in 76%. Plasma cell leukemia (40%) and skull plasmacytomas (65%) were common, suggesting haematological and contiguous spread. Intrathecal (IT) chemotherapy was used in 81%, cranial and/or spinal irradiation in 78%, and various systemic therapies [immunomodulatory agents (IMiDs) (51%), cisplatin‐based (DPACE; cisplatin, doxorubicin, cyclophosphamide, etoposide) (27%), bortezomib (19%), alkylators (11%), dexamethasone alone (8%), auto‐transplant (5%)]. Median survival from CNS disease was only 4·6 months [95% confidence interval (CI): 2·8–6·7]; however, nine patients had prolonged survival (median: 17·1 months, 95% CI: 13·2–67·4). In general, these long‐term survivors were treated with radiotherapy, multi‐dosing IT chemotherapy, and IMiD‐containing therapy. CNS MM is a highly aggressive disease but in our experience, long‐term survival can be achieved with the combination of multi‐dosing IT chemotherapy, radiation and IMiD‐based therapy.

Efficacy, toxicity and mortality of autologous SCT in multiple myeloma patients with dialysis-dependent renal failure

Numerous studies have reported the feasibility and safety of autologous SCT (ASCT) in patients with multiple myeloma (MM) and mild to moderate renal impairment, but there are limited data in dialysis-dependent patients. In this retrospective study, we reviewed the toxicities and efficacy outcomes of 33  MM patients with dialysis-dependent renal failure who underwent ASCT at our institution from 1998 to 2012. The most common grade 3 non-hematologic toxicities were mucositis (49%), infection (15%) and bleeding (6%). Atrial dysrhythmias (24%) and delirium (30%) of all grades were also common. Hematologic toxicities included febrile neutropenia (88%); and RBC and platelet transfusions were required by 71 and 100% of patients, respectively. Transplant-related mortality (TRM) was high at 15%, predominantly caused by septic shock. Response to ASCT was at least VGPR (very good PR) in 50%, PR in 46.2% and stable disease (SD) in 3.8%. Median OS was 5.6 years, comparable to our overall institutional data. Overall, seven patients became dialysis independent. We conclude that ASCT can be an effective treatment for dialysis-dependent MM patients, with high response rates and survival. However, toxicities and a high TRM are observed indicating that further studies are needed to enhance the safety of this approach.

Circulating tumour DNA sequence analysis as an alternative to multiple myeloma bone marrow aspirates

The requirement for bone-marrow aspirates for genomic profiling of multiple myeloma poses an obstacle to enrolment and retention of patients in clinical trials. We evaluated whether circulating cell-free DNA (cfDNA) analysis is comparable to molecular profiling of myeloma using bone-marrow tumour cells. We report here a hybrid-capture-based Liquid Biopsy Sequencing (LB-Seq) method used to sequence all protein-coding exons of KRAS, NRAS, BRAF, EGFR and PIK3CA in 64 cfDNA specimens from 53 myeloma patients to >20,000 × median coverage. This method includes a variant filtering algorithm that enables detection of tumour-derived fragments present in cfDNA at allele frequencies as low as 0.25% (median 3.2%, range 0.25–46%). Using LB-Seq analysis of 48 cfDNA specimens with matched bone-marrow data, we detect 49/51 likely somatic mutations, with subclonal hierarchies reflecting tumour profiling (96% concordance), and four additional mutations likely missed by bone-marrow testing (>98% specificity). Overall, LB-Seq is a high fidelity adjunct to genetic profiling of bone-marrow in multiple myeloma.

Phase I-II trial of oral cyclophosphamide, prednisone and lenalidomide for the treatment of patients with relapsed and refractory multiple myeloma

This single institution, open label Phase I‐II dose escalation trial evaluated the safety and efficacy of the combination of lenalidomide (Revlimid®), cyclophosphamide and prednisone (CPR) in patients with relapsed/refractory multiple myeloma. The maximal administered dose of CPR consisted of cyclophosphamide 300 mg/m2 on day 1, 8, and 15, lenalidomide 25 mg on d 1–21 and prednisone 100 mg every other day in a 28‐d cycle. Between November 2007 and June 2009, 32 patients were entered in cohorts of three at three dose levels. The median age was 64 years, 59% were male, with a median two prior regimens. Responding patients could stay on treatment until progression. The full‐dose CPR regimen produced no dose‐limiting toxicity and was delivered for a median of 16 months (3·5–65 months) with acceptable safety and tolerance. The overall response rate (≥ partial response) was 94% at a median follow up of 28 months. The median progression‐free survival was 16·1 months [95% confidence interval (CI); 10·9–22·5 months], while the median overall survival was 27·6 months (95% CI; 16·8–36·6 months). Only the beta‐2 microglobulin level at protocol entry correlated with a better survival (P = 0·047). These observations compare favourably with other 2‐ and 3‐ drug combinations for relapsed/refractory myeloma, and suggest that CPR should be evaluated further in the setting of relapsed/refractory disease, or in newly diagnosed patients.

RU486-inducible retrovirus-mediated caspase-3 overexpression is cytotoxic to bcl-xL-expressing myeloma cells in vitro and in vivo.

The antiapoptotic protein bcl-x(L) is upregulated in a variety of solid tumors and in primary hematologic malignancies such as multiple myeloma. Activated caspase-3 cleaves proteins essential for cell survival, including bcl-x(L). To explore the potential of caspase-3 as a cytotoxic and immunostimulatory molecule in the treatment of malignancy, an RU486-inducible caspase-3 retrovirus was constructed, validated, and used to transduce first 3T3 and subsequently murine myeloma B9BM1 cells (creating the cell line B9BM-C3). After induction, apoptotic cell death of 3T3 and B9BM-C3 cells began by 4 h and was complete by 48 h postinduction, while nontransduced cells remained viable. Annexin V staining demonstrated 43, 76, and 98% apoptotic cell death at 12, 18, and 24 h postinduction. Activation of caspase-3 was evident in induced cells and cell death could be inhibited by the addition of a caspase-3-specific inhibitor. Overexpression of the myeloma-associated oncogene FGFR3, which upregulates bcl-x(L), delayed but did not prevent caspase-3-mediated killing. B9BM-C3 cells formed tumors after subcutaneous injection in mice. Early treatment with RU486 eradicated tumors; however, rechallenge of treated mice failed to demonstrate evidence of immunoprotection. These results indicate that therapeutic attempts to induce caspase-3 in malignant cells may prove useful in the treatment of bcl-x(L)-expressing tumors.

CyBorD induction therapy in clinical practice

Cyclophosphamide, bortezomib and dexamethasone (CyBorD) is a highly active three-drug induction regimen for untreated transplant-eligible multiple myeloma patients. Although CyBorD has been evaluated only in the phase 2 setting in a limited number of patients, its high efficacy and ease of administration have led to its widespread use. Given that clinical trial efficacy can overestimate real-life effectiveness, we reviewed our institutional experience with 109 newly diagnosed patients who were treated with CyBorD in a non-clinical trial setting. After a median of four cycles, overall response rate (ORR) and very good partial response rate or better (⩾VGPR) were 95 and 66%, respectively, comparable to phase 2 studies of CyBorD and other three/four-drug induction regimens. All patients subsequently underwent successful stem cell collection and upgraded responses to ORR 98% and ⩾VGPR 79% post transplant. At a median follow-up of 19.8 months after diagnosis, the 2-year OS probability was 95.3% (95%CI: 89–98). The presence of concurrent plasmacytoma at diagnosis was the only prognostic factor predicting poorer survival (HR=5.56; 95%CI: 0.92–33.74; P=0.03). CyBorD was well-tolerated, with no severe peripheral neuropathy and minimal hematologic toxicity. Therefore, CyBorD is a convenient, well-tolerated, highly effective induction regimen in preparation for autologous SCT in real-life clinical practice.

Secondary primary malignancies during the lenalidomide–dexamethasone regimen in relapsed/refractory multiple myeloma patients

Lenalidomide in combination with dexamethasone (Len‐dex) represents a highly effective treatment in relapsed/refractory multiple myeloma (RRMM) patients. However, an increased risk of secondary primary malignancies (SPMs), including myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML) has been described in patients receiving lenalidomide. In order to assess the incidence and features of this complication, we reviewed 195 patients with RRMM treated with Len‐dex at our institution. The median follow‐up time from diagnosis of MM was 73 months (10–234 months) and from initiation of Len‐dex was 19 months (1–104 months). The median duration of Len‐dex for all patients was 7.8 months (range 1–90 months). The incidence rate (IR) for all SPMs from start of Len‐dex was 2.37 per 100 patient‐years, which reflected an IR of 1.29 for MDS/AML and 1.08 for nonhematologic malignancies (NHM). MDS was the most common SPM noted. The cumulative IR of SPM at 5 years was 1.54% from the time of MM diagnosis and 5.24% from starting Len‐dex. Multivariable cumulative incidence of SPM analysis identified older age (P = 0.005) and prior number of regimens (P = 0.026) as adverse risk factors. We found more concomitant G‐CSF use (P = 0.029) in patients with MDS/AML, however, causal association is not clear. The progression‐free survival after Len‐dex was the longest for patients in MDS/AML group, and the 5‐year overall survival did not differ among groups. Although the rate of SPM was relatively low with Len‐dex, concomitant G‐CSF should be used judiciously and patients receiving this regimen should be observed for the development of this complication.