Tanespimycin with bortezomib: activity in relapsed/refractory patients with multiple myeloma

Tanespimycin (17‐allylamino‐17‐demethoxygeldanamycin, 17‐AAG) disrupts heat shock protein 90 (HSP90), a key molecular chaperone for signal transduction proteins critical to myeloma growth, survival and drug resistance. In previous studies, tanespimycin monotherapy was well tolerated and active in heavily pretreated patients with relapsed/refractory multiple myeloma (MM). Preclinical data have shown antitumour synergy between tanespimycin and bortezomib, with more pronounced intracellular accumulation of ubiquitinated proteins than either drug alone, an effect attributed to the synergistic suppression of chymotryptic activity in the 20S proteasome. HSP70 induction has been observed in all Phase 1 tanespimycin studies in which it has been measured, with several separate reports of HSP70 overexpression protecting against peripheral nerve injury. In this Phase 2, open‐label multicentre study, we compared 1·3 mg/m² bortezomib + three doses of tanespimycin: 50, 175 and 340 mg/m² in heavily pretreated patients with relapsed and refractory MM and measured HSP70 expression and proteasome activity levels in plasma of treated patients. The study was closed prematurely for resource‐based reasons, precluding dose comparison. Nonetheless, antitumour activity was observed, with promising response rates and promising severity of peripheral neuropathy.     

Inhibition of heat shock protein 90 (HSP90) as a therapeutic strategy for the treatment of myeloma and other cancers

Heat shock protein 90 (HSP90) is a molecular chaperone that is induced in response to cellular stress and stabilizes client proteins involved in cell cycle control and proliferative/anti-apoptotic signalling. HSP90 is overexpressed in a range of cancers, and may contribute to tumour cell survival by stabilizing aberrant signalling proteins and by interfering with apoptosis. Tanespimycin, an HSP90 inhibitor, reduces tumour cell survival in vitro. In multiple myeloma (MM), HSP90 inhibition affects multiple client proteins that contribute to tumour cell survival, including the IGF1 receptor and the IL-6 receptor, and elements of the PI3/Akt, STAT3, and MAPK signalling pathways. HSP90 inhibition also abrogates the protective effect of bone marrow stromal cells and inhibits angiogenesis and osteoclastogenesis. Tanespimycin acts synergistically with the proteasome inhibitor bortezomib in MM cells and tumour explants, possibly reducing their ability to resist bortezomib-induced stress to the endoplasmic reticulum. The combination of tanespimycin and bortezomib has demonstrated significant and durable responses with acceptable toxicity in a phase I/II study in patients with relapsed and relapsed/refractory MM. HSP90 inhibition is a promising strategy in MM especially in combination with bortezomib; additional studies will further evaluate optimal dosings of candidate drugs and schedules, as well as confirm efficacy in comparative phase III trials.     

Bortezomib in combination with intermediate-dose dexamethasone and continuous low-dose oral cyclophosphamide for relapsed multiple myeloma

A phase 2 trial was performed to study the combination of bortezomib (VELCADE) with intermediate-dose dexamethasone (DEX), and continuous low-dose oral cyclophosphamide (CY) in patients with relapsed multiple myeloma (MM). Fifty-four patients with advanced MM were enroled to receive eight 3-week treatment cycles with bortezomib 1.3 mg/m(2) on days 1, 4, 8, and 11, followed by three 5-week cycles with bortezomib 1.3 mg/m(2) on days 1, 8, 15, and 22. Within all cycles, DEX 20 mg/d was given orally on the day of bortezomib injection and the day thereafter. In addition, patients received CY continuous oral treatment at a dose of 50 mg/d p.o. once daily. Fifty patients completing at least one treatment cycle were evaluable for response. Complete, partial, and minor responses occurred in 16%, 66% and 8% of patients, respectively; overall response rate 90% (efficacy analysis). Median event-free survival was 12 months, with a median overall survival of 22 months. Adverse events (AE) of grades 3 or 4 occurring in at least 10% of patients comprised leucopenia, infection, herpes zoster, thrombocytopenia, neuropathy and fatigue. Bortezomib combined with DEX and CY is a highly effective treatment for relapsed MM at an acceptable rate of grade 3/4 AE. Antiviral prophylaxis appears to be mandatory.     

Tanespimycin monotherapy in relapsed multiple myeloma: results of a phase 1 dose‐escalation study

Tanespimycin, a heat shock protein 90 (HSP90) inhibitor, induces apoptosis in drug‐sensitive and ‐resistant MM cell lines and in tumour cells from patients with relapsed MM. In this phase 1 dose‐escalation study, the safety, plasma pharmacokinetics, and biological/antitumour activity of tanespimycin were evaluated in heavily pretreated patients with relapsed/refractory MM. Tanespimycin (150–525 mg/m²) was given on days 1, 4, 8, and 11 of each 3‐week cycle for up to 8 cycles. Non‐haematological AEs included diarrhoea (59%), back pain (35%), fatigue (38%), and nausea (35%); haematological AEs included anaemia (24%) and thrombocytopenia (21%). One patient (3%) achieved minimal response (MR), with a progression‐free survival (PFS) of 3 months, a 41% decrease from baseline in urine M protein, and a 33% decrease from baseline in serum M protein. Fifteen patients (52%) achieved SD with a median PFS of 2·1 months; 5/15 had reductions in serum M protein ranging from 7% to 38% and in urine M protein ranging from 6% to 91%. Mean HSP70 levels increased from day 1 h 0 to day 1 h 4 with further increases on day 11 h 0 and day 11 h 4, consistent with a therapeutic treatment effect. Tanespimycin monotherapy was well tolerated and demonstrated activity across all doses tested.     

Bortezomib, melphalan, prednisone, and thalidomide for relapsed multiple myeloma

In multiple myeloma (MM), the addition of thalidomide or bortezomib to the standard oral melphalan/prednisone combination significantly increased response rate and event-free survival. In this multicenter phase 1/2 trial, dosing, safety, and efficacy of the 4-drug combination, bortezomib, melphalan, prednisone, and thalidomide (VMPT) was determined. Bortezomib was administered at 3 dose levels (1.0 mg/m2, 1.3 mg/m2, or 1.6 mg/m2) on days 1, 4, 15, and 22; melphalan was given at a dose of 6 mg/m2 on days 1 through 5 and prednisone at 60 mg/m2 on days 1 through 5. Thalidomide was delivered at 50 mg on days 1 through 35. Each course was repeated every 35 days. The maximum tolerated dose of bortezomib was 1.3 mg/m2. Thirty patients with relapsed or refractory MM were enrolled; 20 patients (67%) achieved a partial response (PR) including 13 patients (43%) who achieved at least a very good PR. Among 14 patients who received VMPT as second-line treatment, the PR rate was 79% and the immunofixation-negative complete response rate 36%. The 1-year progression-free survival was 61%, and the 1-year survival from study entry was 84%. Grade 3 nonhematologic adverse events included infections (5 patients), fatigue (1), vasculitis (1), and peripheral neuropathy (2); no grade 4 toxicities were recorded. Initial results showed that VMPT is an effective salvage therapy with a very high proportion of responses. The incidence of neurotoxicities was unexpectedly low.     

The potential benefits of participating in early-phase clinical trials in multiple myeloma: long-term remission in a patient with relapsed multiple myeloma treated with 90 cycles of lenalidomide and bortezomib

We present the case of a woman with relapsed multiple myeloma (MM) who received combination lenalidomide and bortezomib therapy for 90 cycles followed by continuous lenalidomide monotherapy and has completed over 100 cycles of treatment to date. The patient was diagnosed with advanced-stage, symptomatic MM in 2001. Following a partial response (PR) to dexamethasone in combination with pamidronate and thalidomide, the patient underwent protocol-directed non-myeloablative allogeneic bone marrow transplantation from her matched sibling donor the following year. In 2004, the patient relapsed and was enrolled in a phase I, dose-escalation trial of lenalidomide plus bortezomib for relapsed and refractory MM. After eight cycles of study treatment, the patient achieved a minimal response. The patient received a total of 90 cycles of treatment with lenalidomide 5 mg given for 14 d every 21 d, and 1 mg/m(2) of bortezomib initially given on days 1, 4, 8, and 11 for the first 20 cycles, and then weekly thereafter on days 1 and 8. Bortezomib was discontinued after 90 cycles, and the patient continued to receive lenalidomide monotherapy. As of cycle 100, the patient achieved a PR. Currently, she is clinically stable with response sustained for over 7 yrs. Therapy has been well tolerated with no significant long-term toxicity; no dose reductions of lenalidomide and bortezomib were required. The excellent tolerability of this steroid-free approach and the durable response seen underscore the potential benefits of participating in early-phase clinical trials evaluating novel therapies and new drug combinations. This case further supports that combination treatment with lenalidomide and bortezomib is an effective therapy in the management of patients with relapsed and refractory MM.     

A phase 2 study of two doses of bortezomib in relapsed or refractory myeloma

In a phase 2 open-label study of the novel proteasome inhibitor bortezomib, 54 patients with multiple myeloma who had relapsed after or were refractory to frontline therapy were randomized to receive intravenous 1.0 or 1.3 mg/m(2) bortezomib twice weekly for 2 weeks, every 3 weeks for a maximum of eight cycles. Dexamethasone was permitted in patients with progressive or stable disease after two or four cycles respectively. Responses were determined using modified European Group for Blood and Marrow Transplantation criteria. The complete response (CR) + partial response (PR) rate for bortezomib alone was 30% [90% confidence interval (CI), 15.7-47.1] and 38% (90% CI, 22.6-56.4) in the 1.0 mg/m(2) (8 of 27 patients) and 1.3 mg/m(2) (10 of 26 patients) groups respectively. The CR + PR rate for patients who received bortezomib alone or in combination with dexamethasone was 37% and 50% for the 1.0 and 1.3 mg/m(2) cohorts respectively. The most common grade 3 adverse events were thrombocytopenia (24%), neutropenia (17%), lymphopenia (11%) and peripheral neuropathy (9%). Grade 4 events were observed in 9% (five of 54 patients). Bortezomib alone or in combination with dexamethasone demonstrated therapeutic activity in patients with multiple myeloma who relapsed after frontline therapy.     

Perifosine plus lenalidomide and dexamethasone in relapsed and relapsed/refractory multiple myeloma: a Phase I Multiple Myeloma Research Consortium study

The combination of lenalidomide-dexamethasone is active in multiple myeloma (MM). Preclinical data showed that the Akt inhibitor, perifosine, sensitized MM cells to lenalidomide and dexamethasone, providing the rationale for this Phase I, multicentre, single-arm study to assess the safety and determine the maximum-tolerated dose (MTD) of perifosine-lenalidomide-dexamethasone in relapsed and relapsed/refractory MM. Patients received escalating doses of perifosine 50-100 mg daily and lenalidomide 15-25 mg once daily on days 1-21 of each 28-d cycle, plus dexamethasone 20-40 mg weekly thereafter, as indicated. Thirty-two patients were enrolled across four dose cohorts. MTD was not reached, with 31 patients evaluable for safety/tolerability. The most common all-causality grade 1-2 adverse events were fatigue (48%) and diarrhoea (45%), and grade 3-4 neutropenia (26%), hypophosphataemia (23%), thrombocytopenia (16%), and leucopenia (13%). Among 30 evaluable patients, 73% (95% confidence interval, 57·5-89·2%) achieved a minimal response or better, including 50% with a partial response or better. Median progression-free survival was 10·8 months and median overall survival 30·6 months. Response was associated with phospho-Akt in pharmacodynamic studies. Perifosine-lenalidomide-dexamethasone was well tolerated and demonstrated encouraging clinical activity in relapsed and relapsed/refractory MM.     

Therapy with Bortezomib plus Dexamethasone Induces Osteoblast Activation in Responsive Patients with Multiple Myeloma

Bortezomib is a novel proteasome inhibitor that has shown marked antitumor effects in patients with multiple myeloma (MM). We evaluated the feasibility and efficacy of bortezomib plus dexamethasone (BD) therapy and assessed bone metabolism in relapsed or refractory MM. Fourteen patients received 1.3 mg/m2 bortezomib on days 1, 4, 8, and 11 along with 20 mg/dose of dexamethasone on days 1, 2, 4, 5, 8, 9, 11, and 12 in a 21-day cycle. After 1 to 3 cycles of BD therapy, 9 patients (64%) achieved an objective response (5 very good partial responses and 4 partial responses). Notably, a rapid increase in the serum concentration of alkaline phosphatase (ALP) was observed in 6 of the treatment-responsive patients. Moreover, serum levels of bone-formation markers (bone-specific ALP and osteocalcin) significantly increased in 5 and 2 responsive patients, respectively. Radiographic examination showed improvement in bone lesions, suggesting that BD therapy induces osteoblast activation in responders. Adverse events included thrombocytopenia of grades 1 to 3, peripheral neuropathy of grades 1 to 2, and grade 3 ileus and were transient and manageable. Although severe lung injury has been reported among Japanese patients treated with bortezomib, no pulmonary complications were observed during BD therapy. Our results suggest that BD therapy is a safe and promising therapeutic approach for Japanese patients with MM.     

Bortezomib, low-dose intravenous melphalan, and dexamethasone for patients with relapsed multiple myeloma

This multicenter phase I/II study investigated the maximum tolerated dose (MTD), safety, and efficacy of low dose intravenous (IV) melphalan in combination with bortezomib for patients with relapsed multiple myeloma (MM). Patients received bortezomib 1·3 mg/m² on days 1, 4, 8, and 11 and escalating doses of IV melphalan (2·5–10·0 mg/m²) on day 2 of a 28-day cycle for a maximum of eight cycles. Dexamethasone 20 mg was added for progressive or stable disease. Fifty-three patients were enrolled. The MTD was defined at melphalan 7·5 mg/m² and bortezomib 1·3 mg/m². The overall response rate (ORR) was 68% (23% complete or near-complete responses [CR/nCR]) whilst at the MTD ( n  = 33) the ORR was 76% (34% CR/nCR). After median follow-up of 17 months, the median progression free survival was 10 months, rising to 12 months at the MTD ( P  < 0·05 vs. non-MTD regimens). The median overall survival was 28 months, but was not yet reached at the MTD. Grade 3/4 adverse events included thrombocytopenia (62%), neutropenia (57%), infection (21%), and neuropathy (15%). Bortezomib and low-dose IV melphalan combination therapy is a safe and highly effective regimen for patients with relapsed MM. These data suggest further investigation of this combination is warranted.     

Efficacy and safety of once-weekly and twice-weekly bortezomib in patients with relapsed systemic AL amyloidosis: results of a phase 1/2 study

This first prospective phase 2 study of single-agent bortezomib in relapsed primary systemic AL amyloidosis evaluated the recommended (maximum planned) doses identified in phase 1 testing (1.6 mg/m2 once weekly [days 1, 8, 15, and 22; 35-day cycles]; 1.3 mg/m2 twice weekly [days 1, 4, 8, and 11; 21-day cycles]). Among all 70 patients enrolled in the study, 44% had ≥ 3 organs involved, including 73% and 56% with renal and cardiac involvement. In the 1.6 mg/m2 once-weekly and 1.3 mg/m2 twice-weekly groups, the hematologic response rate was 68.8% and 66.7% (37.5% and 24.2% complete responses, respectively); median time to first/best response was 2.1/3.2 and 0.7/1.2 months, and 78.8% and 75.5% had response durations of ≥ 1 year, respectively. One-year hematologic progression-free rates were 72.2% and 74.6%, and 1-year survival rates were 93.8% and 84.0%, respectively. Outcomes appeared similar in patients with cardiac involvement. Among all 70 patients, organ responses included 29% renal and 13% cardiac responses. Rates of grade ≥ 3 toxicities (79% vs 50%) and discontinuations/dose reductions (38%/53% vs 28%/22%) resulting from toxicities appeared higher with 1.3 mg/m2 twice-weekly versus 1.6 mg/m2 once-weekly dosing. Both bortezomib dose schedules represent active, well-tolerated regimens in relapsed AL amyloidosis. This study was registered at www.clinicaltrials.gov as #NCT00298766.     

Safety and efficacy of bortezomib and melphalan combination in patients with relapsed or refractory multiple myeloma: updated results of a phase 1/2 study after longer follow-up

Bortezomib synergizes with melphalan in preclinical and early clinical studies. Updated data from our phase 1/2 study assessing the safety and efficacy of bortezomib plus melphalan in relapsed/refractory multiple myeloma (MM) are presented. Bortezomib (0.7, 1.0, or 1.3 mg/m(2)) on days 1, 4, 8, and 11 and oral melphalan (0.025-0.25 mg/kg) on days 1-4 of a 28-day cycle were administered. Hematologic toxicities defined the maximum tolerated dose as bortezomib 1.0 mg/m(2) and melphalan 0.10 mg/kg. Because dose-limiting toxicities were attributed to the more myelosuppressive melphalan, cohorts 9 and 10 with higher bortezomib (1.3 mg/m(2)) and lower melphalan (0.025 and 0.10 mg/kg) doses were added. Responses occurred in 32/46 (70%) evaluable patients: two complete (4%), five near-complete (11%), 16 partial (35%), and nine minimal (20%). Complete and near-complete responses were observed only with higher bortezomib doses. Response rates were similar in patients with prior melphalan or bortezomib. Median progression-free survival was 9 months (range, 1-24), and overall survival was 32 months (range, 1-54). The most common grade 3/4 hematologic adverse events (AEs) were neutropenia (31%/0%), thrombocytopenia (25%/2%), and anemia (13%/0%). Grade 4 tumor lysis syndrome was reported in one patient. Fewer grade 3/4 hematologic AEs were reported in cohorts 9 and 10 than in cohorts receiving lower bortezomib and higher melphalan doses. In conclusion, bortezomib plus melphalan is a steroid- and immunomodulatory drug-free regimen that may provide a treatment alternative for elderly patients and patients with significant comorbidity.     

A high rate of durable responses with romidepsin, bortezomib, and dexamethasone in relapsed or refractory multiple myeloma

We report results from a study exploring the combination of romidepsin, bortezomib, and dexamethasone for the treatment of patients with multiple myeloma (MM) previously treated with > 1 prior therapy. The primary objective was to determine the maximum tolerated dose (MTD) of the combination using a novel accelerated dose-escalation schedule in patients with relapsed or refractory MM. The secondary objective was to determine overall response (OR), time to progression (TTP), and overall survival (OS). The MTD identified was bortezomib 1.3 mg/m(2) (days 1, 4, 8, and 11), dexamethasone 20 mg (days 1, 2, 4, 5, 8, 9, 11, and 12), and romidepsin 10 mg/m(2) (days 1, 8, and 15) every 28 days. Thrombocytopenia (64%) was the most common ≥ grade 3 hematologic toxicity. Peripheral neuropathy occurred in 76% of patients (n = 19) (≥ grade 3, 8%; 95% confidence interval [CI] 1%-26%). Maintenance romidepsin 10 mg/m(2) (on days 1 and 8 of a 28-day cycle) proved feasible, with 12 patients receiving a median of 7.5 cycles (range: 1-29). An OR (M-protein) of > minor response (MR) was seen in 18 of 25 patients (72%); 2 (8%) had complete remissions (CRs) and 13 (52%) had partial responses (PRs), including 7 (28%) with very good PRs (VGPRs). The median TTP was 7.2 (95% CI: 5.5-19.6) months, and the median OS was > 36 months. This regimen shows activity with manageable toxicity and warrants further evaluation. This trial was registered at www.clinicaltrials.gov as NCT00431990.     

Phase I/II trial assessing bendamustine plus bortezomib combination therapy for the treatment of patients with relapsed or refractory multiple myeloma

Bendamustine, active in multiple myeloma (MM), is a bifunctional mechlorethamine derivative with alkylating properties. Bortezomib, approved to treat MM, is effective in combination with alkylators. The tolerability and efficacy of bendamustine plus bortezomib in relapsed/refractory MM was assessed in an open‐label, dose‐escalating, phase I/II study. Patients aged ≥18 years received intravenous bendamustine 50, 70, or 90 mg/m² (days 1 and 4) plus bortezomib 1·0 mg/m² (days 1, 4, 8, and 11) for up to eight 28‐day cycles. No dose‐limiting toxicity was observed after cycle 1; bendamustine 90 mg/m² plus bortezomib 1·0 mg/m² was designated the maximum tolerated dose (MTD). The most common grade 3/4 adverse events were leucopenia (58%), neutropenia (50%), lymphopenia (45%), and thrombocytopenia (30%). Primary efficacy measure was overall response rate (ORR), which was the combined complete response (CR), very good partial response (VGPR), partial response (PR), and minimal response (MR). ORR was 48% (one CR, two VGPR, nine PR, and seven MR) for all 40 enrolled patients, 52% (16/31) at the MTD (90 mg/m²), and 42% and 46% for prior use of bortezomib (n = 31) or alkylators (n = 28) respectively. Bendamustine plus bortezomib was well tolerated with promising efficacy in this heavily pretreated population.     

A comparison of bortezomib, cyclophosphamide, and dexamethasone (Vel-CD) chemotherapy without and with thalidomide (Vel-CTD) for the treatment of relapsed or refractory multiple myeloma

We compared the clinical responses and toxicities between bortezomib-based salvage chemotherapy combined with cyclophosphamide, thalidomide, and dexamethasone(Vel-CTD) and without thalidomide (Vel-CD) in patients with relapsed or refractory MM. Eighty-six patients received at least two cycles of treatment with Vel-CTD (bortezomib 1.3 mg/m2 i.v. on days 1, 4, 8, and 11; cyclophosphamide 150 mg/m2 orally on days 1–4; thalidomide 50–100 mg/day orally every day; and dexamethasone 20 mg/m2 i.v. on days 1, 4, 8, and 11 every 3 weeks), and 67 patients were given at least two cycles of Vel-CD, which is the same regimen as Vel-CTD except without thalidomide. The overall response rates of the Vel-CD and Vel-CTD groups were 88% and 90% (p>0.05), respectively. There was no difference in the progression free survival (p = 0.69) and overall survival rates(p = 0.49) between the two groups. Grade 3 or more adverse hematologic events occurred in the same proportion of patients in both groups. In terms of non-hematologic toxicities, the Vel-CTD group showed a higher proportion of autonomic neuropathy, motor neuropathy, and sensory neuropathy compared to the Vel-CD group (each, p<0.05). Only three patients in the Vel-CTD group showed thrombotic events despite aspirin prophylaxis. The Vel-CD regimen inpatients with relapsed or refractory MM is an effective and more tolerable salvage therapy compared to Vel-CTD in terms of its comparable response rate and less severe of non-hematologic toxicities.     

Safety and efficacy of pomalidomide,dexamethasone and pegylated liposomal doxorubicin for patients with relapsed or refractory multiple myeloma

Immunomodulatory drugs including thalidomide, lenalidomide (LEN) and pomalidomide (POM), are effective for treating multiple myeloma (MM). POM has shown enhanced efficacy with dexamethasone (DEX). Pegylated liposomal doxorubicin (PLD) with bortezomib is US Food and Drug Administration‐approved for treating MM. PLD with LEN or thalidomide has shown efficacy for MM patients. LEN with DEX, PLD and bortezomib achieves high response rates. We evaluated the combination of POM with DEX 40 mg and PLD 5 mg/m² with the latter two drugs administered on days 1, 4, 8 and 11 on a 28‐day cycle for the treatment of relapsed/refractory MM patients. During Phase 1, the maximum tolerated dose of POM was 4 mg, and was used in Phase 2, which also required patients to be refractory to LEN. However, neutropenia ≥ grade 3 was observed in 10/17 (59%) patients, and the dose was lowered to 3 mg. Median PFS was 5·4 months (range, 0·3–29·0 +  months). Overall response rates for patients in Phase 2 were 39% and 31% among subjects receiving POM at 3 mg and 4 mg, respectively, and clinical benefit rates were 51% and 44%, respectively. POM, PLD and DEX is a treatment option for relapsed/refractory MM patients including those who are refractory to LEN.     

Good clinical activity and favorable toxicity profile of once weekly bortezomib,fotemustine, and dexamethasone (B‐MuD) for the treatment of relapsed multiple myeloma

Since multiple myeloma (MM) is still not‐curable, the management of relapse remains challenging. Given the known efficacy of alkylating agents in MM, we conducted a phase I/II study to test a new three drug combination in which Fotemustine (Muphoran), an alkylating agent of nitrosurea family, was added to bortezomib + dexamethasone backbone (B‐MuD) for the treatment of MM relapsed patients. Fotemustine was administered at two dose levels (80–100 mg/m² i.v.) on day 1. The original 21‐day schedule was early amended for extra‐hematological toxicity and a 35‐day schedule was adopted (Bortezomib 1.3 mg/m² i.v. on days 1, 8, 15, and 22, Dexamethasone 20 mg i.v. on days 1, 8, 15, and 22) for a total of six courses. Twenty‐four patients were enrolled. The maximum tolerated dose of Fotemustine was 100 mg/m². The overall response rate was of 62% (CR 8%, VGPR 33%, and PR 21%). The median OS was 28.5 months, the median progression‐free survival (PFS) was 19.1 months. B‐MuD resulted effective in patients previous exposed to bortezomib without difference of response (P = 0.25) and PFS (P = 0.87) when compared to bortezomib‐naive patients. Thrombocytopenia was the most common AE overall. In conclusion, B‐MuD is an effective and well tolerated combination in relapsed MM patients even in advanced disease phase. © Am. J. Hematol., 88:102–106, 2013. © 2012 Wiley Periodicals, Inc.     

Phase I and pharmacological study of cytarabine and tanespimycin in relapsed and refractory acute leukemia

Background

In preclinical studies the heat shock protein 90 (Hsp90) inhibitor tanespimycin induced down-regulation of checkpoint kinase 1 (Chk1) and other client proteins as well as increased sensitivity of acute leukemia cells to cytarabine. We report here the results of a phase I and pharmacological study of the cytarabine + tanespimycin combination in adults with recurrent or refractory acute leukemia.

Design and Methods

Patients received cytarabine 400 mg/m²/day continuously for 5 days and tanespimycin infusions at escalating doses on days 3 and 6. Marrow mononuclear cells harvested before therapy, immediately prior to tanespimycin, and 24 hours later were examined by immunoblotting for Hsp70 and multiple Hsp90 clients.

Results

Twenty-six patients were treated at five dose levels. The maximum tolerated dose was cytarabine 400 mg/m²/day for 5 days along with tanespimycin 300 mg/m² on days 3 and 6. Treatment-related adverse events included disseminated intravascular coagulation (grades 3 and 5), acute respiratory distress syndrome (grade 4), and myocardial infarction associated with prolonged exposure to tanespimycin and its active metabolite 17-aminogeldanamycin. Among 21 evaluable patients, there were two complete and four partial remissions. Elevations of Hsp70, a marker used to assess Hsp90 inhibition in other studies, were observed in more than 80% of samples harvested 24 hours after tanespimycin, but down-regulation of Chk1 and other Hsp90 client proteins was modest.

Conclusions

Because exposure to potentially effective concentrations occurs only for a brief time in vivo, at clinically tolerable doses tanespimycin has little effect on resistance-mediating client proteins in relapsed leukemia and exhibits limited activity in combination with cytarabine.     

A modified regimen of pegylated liposomal doxorubicin,bortezomib, and dexamethasone is effective and well tolerated in the treatment of relapsed or refractory multiple myeloma

Preclinical and clinical studies have demonstrated synergy between bortezomib and pegylated liposomal doxorubicin (PLD) for relapsed/refractory (R/R) multiple myeloma (MM) patients compared to bortezomib as a single agent. This retrospective study evaluated the efficacy and safety of a more frequent low-dose schedule of PLD, bortezomib, and intravenous dexamethasone (DVD) for patients with R/R MM, many of whom were previously treated with bortezomib. Twenty-eight patients with R/R MM were treated, and 23 (83%) had been previously treated with ≥1 bortezomib-containing regimen. Treatment consisted of dexamethasone 40 mg intravenously, bortezomib 1.0 mg/m², and PLD 5.0 mg/m² on days 1, 4, 8, and 11 of a 28-day cycle for a maximum of eight cycles. Patients ranged from 33 to 81 years of age (median, 67) and had received 1–14 prior therapies (median, 5). At baseline, ten, nine, and nine patients were in stages I, II, and III, respectively, as defined by the International Staging System, and eight (29%) patients had elevated serum creatinine levels. The overall response rate was 61%, which included one (4%) complete response, three (11%) very good partial responses, eight (29%) partial responses, and five (18%) minimal responses. Of the 23 patients who had previously received bortezomib, 12 (52%) responded. The regimen was well tolerated with only six patients (21%) who showed worsening of their baseline peripheral neuropathy (PN). One patient discontinued this regimen due to an adverse event (grade II PN). DVD appears to represent a well-tolerated regimen with a high response rate for the treatment of R/R MM patients.     

High response rate to bortezomib with or without dexamethasone in patients with relapsed or refractory multiple myeloma: results of a global phase 3b expanded access program

Phase 2 trials have demonstrated that bortezomib ± dexamethasone is safe and effective in relapsed multiple myeloma (MM). In this multicentre, open-label, phase 3b trial, 638 patients with relapsed or refractory MM (median 3 prior therapies) received bortezomib 1·3 mg/m² on days 1, 4, 8, and 11 of a maximum of eight 3-week cycles (median 5 cycles). Dexamethasone 20 mg/d was added the day of and day after each bortezomib dose for progressive disease after ≥2 cycles or for stable disease after ≥4 cycles. Responses were assessed based on M-protein changes. Overall response rate was 67%, including 11% complete (100% M-protein reduction), 22% very good partial (75–99% reduction), 18% partial (50–74% reduction), and 16% minimal response (25–49% reduction). Dexamethasone was added in 208 patients (33%), of whom 70 (34%) showed improved response. Median time to best response of minimal response or better was 84 d. Most common grade 3/4 adverse events were thrombocytopenia (39%), neutropenia (16%), anaemia (12%), diarrhoea (7%), and peripheral neuropathy (6%). Neuropathy (any grade) was seen in 25% of the patients and led to discontinuation in 5%. Bortezomib, alone and combined with dexamethasone, is safe and effective in heavily pretreated patients with relapsed or refractory MM.