Robert Z. Orlowski

Phase I Trial of the Proteasome Inhibitor PS-341 in Patients With Refractory Hematologic Malignancies

PURPOSE To determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacodynamics (PD) of the proteasome inhibitor bortezomib (previously known as PS-341) in patients with refractory hematologic malignancies. PATIENTS AND METHODS Patients received PS-341 twice weekly for 4 weeks at either 0.40, 1.04, 1.20, or 1.38 mg/m(2), followed by a 2-week rest. The PD of PS-341 was evaluated by measurement of whole blood 20S proteasome activity. RESULTS Twenty-seven patients received 293 doses of PS-341, including 24 complete cycles. DLTs at doses above the 1.04-mg/m(2) MTD attributed to PS-341 included thrombocytopenia, hyponatremia, hypokalemia, fatigue, and malaise. In three of 10 patients receiving additional therapy, serious reversible adverse events appeared during cycle 2, including one episode of postural hypotension, one systemic hypersensitivity reaction, and grade 4 transaminitis in a patient with hepatitis C and a substantial acetaminophen ingestion. PD studies revealed PS-341 induced 20S proteasome inhibition in a time-dependent manner, and this inhibition was also related to both the dose in milligrams per meter squared, and the absolute dose of PS-341. Among nine fully assessable patients with heavily pretreated plasma cell dyscrasias completing one cycle of therapy, there was one complete response and a reduction in paraprotein levels and/or marrow plasmacytosis in eight others. In addition, one patient with mantle cell lymphoma and another with follicular lymphoma had shrinkage of nodal disease. CONCLUSION PS-341 was well tolerated at 1.04 mg/m(2) on this dose-intensive schedule, although patients need to be monitored for electrolyte abnormalities and late toxicities. Additional studies are indicated to determine whether incorporation of dose/body surface area yields a superior PD model to dosing without normalization. PS-341 showed activity against refractory multiple myeloma and possibly non-Hodgkins lymphoma in this study, and merits further investigation in these populations.

Randomized Phase III Study of Pegylated Liposomal Doxorubicin Plus Bortezomib Compared With Bortezomib Alone in Relapsed or Refractory Multiple Myeloma: Combination Therapy Improves Time to Progression

PURPOSE This phase III international study compared the efficacy and safety of a combination of pegylated liposomal doxorubicin (PLD) plus bortezomib with bortezomib monotherapy in patients with relapsed or refractory multiple myeloma. PATIENTS AND METHODS Six hundred forty-six patients were randomly assigned to receive either intravenous bortezomib 1.3 mg/m(2) on days 1, 4, 8, and 11 of an every 21-days cycle, or the same bortezomib regimen with PLD 30 mg/m(2) on day 4. RESULTS Median time to progression was increased from 6.5 months for bortezomib to 9.3 months with the PLD + bortezomib combination (P = .000004; hazard ratio, 1.82 [monotherapy v combination therapy]; 95% CI, 1.41 to 2.35). The 15-month survival rate for PLD + bortezomib was 76% compared with 65% for bortezomib alone (P = .03). The complete plus partial response rate was 41% for bortezomib and 44% for PLD + bortezomib, a difference that was not statistically significant. Median duration of response was increased from 7.0 to 10.2 months (P = .0008) with PLD + bortezomib. Grade 3/4 adverse events were more frequent in the combination group (80% v 64%), with safety profiles consistent with the known toxicities of the two agents. An increased incidence in the combination group was seen of grade 3/4 neutropenia, thrombocytopenia, asthenia, fatigue, diarrhea, and hand-foot syndrome. CONCLUSION PLD with bortezomib is superior to bortezomib monotherapy for the treatment of patients with relapsed or refractory multiple myeloma. The combination therapy is associated with a higher incidence of grade 3/4 myelosuppression, constitutional symptoms, and GI and dermatologic toxicities.

Prevention of thalidomide- and lenalidomide-associated thrombosis in myeloma

The incidence of venous thromboembolism (VTE) is more than 1‰ annually in the general population and increases further in cancer patients. The risk of VTE is higher in multiple myeloma (MM) patients who receive thalidomide or lenalidomide, especially in combination with dexamethasone or chemotherapy. Various VTE prophylaxis strategies, such as low-molecular-weight heparin (LMWH), warfarin or aspirin, have been investigated in small, uncontrolled clinical studies. This manuscript summarizes the available evidence and recommends a prophylaxis strategy according to a risk-assessment model. Individual risk factors for thrombosis associated with thalidomide/lenalidomide-based therapy include age, history of VTE, central venous catheter, comorbidities (infections, diabetes, cardiac disease), immobilization, surgery and inherited thrombophilia. Myeloma-related risk factors include diagnosis and hyperviscosity. VTE is very high in patients who receive high-dose dexamethasone, doxorubicin or multiagent chemotherapy in combination with thalidomide or lenalidomide, but not with bortezomib. The panel recommends aspirin for patients with ⩽1 risk factor for VTE. LMWH (equivalent to enoxaparin 40 mg per day) is recommended for those with two or more individual/myeloma-related risk factors. LMWH is also recommended for all patients receiving concurrent high-dose dexamethasone or doxorubicin. Full-dose warfarin targeting a therapeutic INR of 2–3 is an alternative to LMWH, although there are limited data in the literature with this strategy. In the absence of clear data from randomized studies as a foundation for recommendations, many of the following proposed strategies are the results of common sense or derive from the extrapolation of data from many studies not specifically designed to answer these questions. Further investigation is needed to define the best VTE prophylaxis.

Frequency, Characteristics, and Reversibility of Peripheral Neuropathy During Treatment of Advanced Multiple Myeloma With Bortezomib

PURPOSE To determine the frequency, characteristics, and reversibility of peripheral neuropathy from bortezomib treatment of advanced multiple myeloma. PATIENTS AND METHODS Peripheral neuropathy was assessed in two phase II studies in 256 patients with relapsed and/or refractory myeloma treated with bortezomib 1.0 or 1.3 mg/m2 intravenous bolus on days 1, 4, 8, and 11, every 21 days, for up to eight cycles. Peripheral neuropathy was evaluated at baseline, during the study, and after the study by patient-reported symptoms using the Functional Assessment of Cancer Therapy Scale/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) questionnaire and neurologic examination. During the study, peripheral neuropathy was also evaluated by investigator assessment. A subset of patients underwent nerve conduction studies (n = 13). RESULTS Before treatment, 194 (81%) of 239 patients had peripheral neuropathy by FACT/GOG-Ntx questionnaire, and 203 (83%) of 244 patients had peripheral neuropathy by neurologic examination. Treatment-emergent neuropathy was reported in 35% of patients, including 37% (84 of 228 patients) receiving bortezomib 1.3 mg/m2 and 21% (six of 28 patients) receiving bortezomib 1.0 mg/m2. Grade 1 or 2, 3, and 4 neuropathy occurred in 22%, 13%, and 0.4% of patients, respectively. The incidence of grade > or = 3 neuropathy was higher among patients with baseline neuropathy by FACT/GOG-Ntx questionnaire compared with patients without baseline neuropathy (14% v 4%, respectively). In all 256 patients, neuropathy led to dose reduction in 12% and discontinuation in 5%. Of 35 patients with neuropathy > or = grade 3 and/or requiring discontinuation, resolution to baseline or improvement occurred in 71%. CONCLUSION Bortezomib-associated peripheral neuropathy seemed reversible in the majority of patients after dose reduction or discontinuation. Although severe neuropathy was more frequent in the presence of baseline neuropathy, the overall occurrence was independent of baseline neuropathy or type of prior therapy.

Proteasome Inhibitors in Cancer Therapy: Lessons from the First Decade

The ubiquitin-proteasome pathway is involved in intracellular protein turnover, and its function is crucial to cellular homeostasis. First synthesized as probes of proteolytic processes, proteasome inhibitors began to be thought of as potential drug candidates when they were found to induce programmed cell death preferentially in transformed cells. They made their first leap into the clinic to be tested as therapeutic agents 10 years ago, and since then, great strides have been made in defining their mechanisms of action, their clinical efficacy and toxicity, and some of their limitations in the form of resistance pathways. Validation of the ubiquitin-proteasome pathway as a target for cancer therapy has come in the form of approvals of the first such inhibitor, bortezomib, for relapsed/refractory multiple myeloma and mantle cell lymphoma, for which this agent has become a standard of care. Lessons learned from this first-in-class agent are now being applied to the development of a new generation of proteasome inhibitors that hold the promise of efficacy in bortezomib-resistant disease and possibly in a broader spectrum of diseases. This saga provides a salient example of the promise of translational medicine and a paradigm by which other agents may be successfully brought from the bench to the bedside.

NF-κB as a therapeutic target in cancer

Abstract The transcription factor nuclear factor (NF)-κB is activated in certain cancers and in response to chemotherapy and radiation. The transcriptional activation of genes associated with cell proliferation, angiogenesis, metastasis and suppression of apoptosis appears to lie at the heart of the ability of NF-κB to promote oncogenesis and cancer therapy resistance. Supporting these findings are recent experiments, performed in vitro and using xenograft models of cancer, which implicate NF-κB inhibition as an important new approach for the treatment of certain hematological malignancies and as an adjuvant approach in combination with chemotherapy or radiation for a variety of cancers. Clinical trials with drugs that block NF-κB are currently in progress with promising results. However, as there is currently no drug that blocks specific NF-κB activation, conclusions drawn with small-molecule inhibitors must be interpreted carefully.

Elotuzumab Therapy for Relapsed or Refractory Multiple Myeloma

BACKGROUND Elotuzumab, an immunostimulatory monoclonal antibody targeting signaling lymphocytic activation molecule F7 (SLAMF7), showed activity in combination with lenalidomide and dexamethasone in a phase 1b-2 study in patients with relapsed or refractory multiple myeloma. METHODS In this phase 3 study, we randomly assigned patients to receive either elotuzumab plus lenalidomide and dexamethasone (elotuzumab group) or lenalidomide and dexamethasone alone (control group). Coprimary end points were progression-free survival and the overall response rate. Final results for the coprimary end points are reported on the basis of a planned interim analysis of progression-free survival. RESULTS Overall, 321 patients were assigned to the elotuzumab group and 325 to the control group. After a median follow-up of 24.5 months, the rate of progression-free survival at 1 year in the elotuzumab group was 68%, as compared with 57% in the control group; at 2 years, the rates were 41% and 27%, respectively. Median progression-free survival in the elotuzumab group was 19.4 months, versus 14.9 months in the control group (hazard ratio for progression or death in the elotuzumab group, 0.70; 95% confidence interval, 0.57 to 0.85; P<0.001). The overall response rate in the elotuzumab group was 79%, versus 66% in the control group (P<0.001). Common grade 3 or 4 adverse events in the two groups were lymphocytopenia, neutropenia, fatigue, and pneumonia. Infusion reactions occurred in 33 patients (10%) in the elotuzumab group and were grade 1 or 2 in 29 patients. CONCLUSIONS Patients with relapsed or refractory multiple myeloma who received a combination of elotuzumab, lenalidomide, and dexamethasone had a significant relative reduction of 30% in the risk of disease progression or death. (Funded by Bristol-Myers Squibb and AbbVie Biotherapeutics; ELOQUENT-2 ClinicalTrials.gov number, NCT01239797.).

A phase 2 study of single-agent carfilzomib (PX-171-003-A1) in patients with relapsed and refractory multiple myeloma

Carfilzomib is a next-generation, selective proteasome inhibitor being evaluated for the treatment of relapsed and refractory multiple myeloma. In this open-label, single-arm phase 2 study (PX-171-003-A1), patients received single-agent carfilzomib 20 mg/m(2) intravenously twice weekly for 3 of 4 weeks in cycle 1, then 27 mg/m(2) for ≤ 12 cycles. The primary endpoint was overall response rate (≥ partial response). Secondary endpoints included clinical benefit response rate (≥ minimal response), duration of response, progression-free survival, overall survival, and safety. A total of 266 patients were evaluable for safety, 257 for efficacy; 95% were refractory to their last therapy; 80% were refractory or intolerant to both bortezomib and lenalidomide. Patients had median of 5 prior lines of therapy, including bortezomib, lenalidomide, and thalidomide. Overall response rate was 23.7% with median duration of response of 7.8 months. Median overall survival was 15.6 months. Adverse events (AEs) were manageable without cumulative toxicities. Common AEs were fatigue (49%), anemia (46%), nausea (45%), and thrombocytopenia (39%). Thirty-three patients (12.4%) experienced peripheral neuropathy, primarily grades 1 or 2. Thirty-three patients (12.4%) withdrew because of an AE. Durable responses and an acceptable tolerability profile in this heavily pretreated population demonstrate the potential of carfilzomib to offer meaningful clinical benefit. This trial was registered at www.clinicaltrials.gov as #NCT00511238.

Consensus recommendations for the uniform reporting of clinical trials: report of the International Myeloma Workshop Consensus Panel 1

It is essential that there be consistency in the conduct, analysis, and reporting of clinical trial results in myeloma. The goal of the International Myeloma Workshop Consensus Panel 1 was to develop a set of guidelines for the uniform reporting of clinical trial results in myeloma. This paper provides a summary of the current response criteria in myeloma, detailed definitions for patient populations, lines of therapy, and specific endpoints. We propose that future clinical trials in myeloma follow the guidelines for reporting results proposed in this manuscript.

Risk of progression and survival in multiple myeloma relapsing after therapy with IMiDs and bortezomib: A multicenter international myeloma working group study

Promising new drugs are being evaluated for treatment of multiple myeloma (MM), but their impact should be measured against the expected outcome in patients failing current therapies. However, the natural history of relapsed disease in the current era remains unclear. We studied 286 patients with relapsed MM, who were refractory to bortezomib and were relapsed following, refractory to or ineligible to receive, an IMiD (immunomodulatory drug), had measurable disease, and ECOG PS of 0, 1 or 2. The date patients satisfied the entry criteria was defined as time zero (T0). The median age at diagnosis was 58 years, and time from diagnosis to T0 was 3.3 years. Following T0, 213 (74%) patients had a treatment recorded with one or more regimens (median=1; range 0–8). The first regimen contained bortezomib in 55 (26%) patients and an IMiD in 70 (33%). A minor response or better was seen to at least one therapy after T0 in 94 patients (44%) including ⩾partial response in 69 (32%). The median overall survival and event-free survival from T0 were 9 and 5 months, respectively. This study confirms the poor outcome, once patients become refractory to current treatments. The results provide context for interpreting ongoing trials of new drugs.