Donna M. Weber

Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group

Summary. The monoclonal gammopathies are a group of disorders associated with monoclonal proliferation of plasma cells. The characterization of specific entities is an area of difficulty in clinical practice. The International Myeloma Working Group has reviewed the criteria for diagnosis and classification with the aim of producing simple, easily used definitions based on routinely available investigations. In monoclonal gammopathy of undetermined significance (MGUS) or monoclonal gammopathy, unattributed/unassociated (MG[u]), the monoclonal protein is < 30 g/l and the bone marrow clonal cells < 10% with no evidence of multiple myeloma, other B‐cell proliferative disorders or amyloidosis. In asymptomatic (smouldering) myeloma the M‐protein is ≥ 30 g/l and/or bone marrow clonal cells ≥ 10% but no related organ or tissue impairment (ROTI)(end‐organ damage), which is typically manifested by increased calcium, renal insufficiency, anaemia, or bone lesions (CRAB) attributed to the plasma cell proliferative process. Symptomatic myeloma requires evidence of ROTI. Non‐secretory myeloma is characterized by the absence of an M‐protein in the serum and urine, bone marrow plasmacytosis and ROTI. Solitary plasmacytoma of bone, extramedullary plasmacytoma and multiple solitary plasmacytomas (± recurrent) are also defined as distinct entities. The use of these criteria will facilitate comparison of therapeutic trial data. Evaluation of currently available prognostic factors may allow better definition of prognosis in multiple myeloma.

Thalidomide Alone or With Dexamethasone for Previously Untreated Multiple Myeloma

PURPOSE To evaluate the activity of thalidomide in patients with asymptomatic multiple myeloma and of thalidomide-dexamethasone in patients with previously untreated symptomatic myeloma. PATIENTS AND METHODS Twenty-eight patients with previously untreated asymptomatic myeloma were treated with thalidomide 100 to 200 mg orally (PO) at bedtime (qhs) with serial increments of 50 to 100 mg at weekly intervals, as tolerated to a maximum of 600 mg PO qhs. Forty consecutive previously untreated patients with symptomatic myeloma were also treated as above (maximum dose 400 mg) and received dexamethasone 20 mg/m(2) for 4 days beginning on days 1, 9, and 17; the second and third cycles of repeated dexamethasone were begun on day 30. Both groups of patients were treated for at least 3 months. RESULTS The response rate was 36% for patients treated with thalidomide alone and 72% for patients treated with thalidomide-dexamethasone, the latter including complete remission in 16% of patients. The median time to remission was 4.2 months with thalidomide alone and 0.7 months with thalidomide-dexamethasone. Grade 3 toxicity included infections (nine patients) and thrombotic/embolic events (seven patients). Five deaths have occurred as a result of multiple myeloma (two patients), infection (one patient), unknown cause (one patient), and a possible thromboembolic event (one patient). CONCLUSION Thalidomide alone was effective in patients with newly diagnosed myeloma. The combination with dexamethasone induced a high frequency of response, rapid onset of remission, and low incidence of serious irreversible toxicity. These observations support further studies of this promising combination for patients with newly diagnosed multiple myeloma.

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.

Long-term follow-up on overall survival from the MM-009 and MM-010 phase III trials of lenalidomide plus dexamethasone in patients with relapsed or refractory multiple myeloma.

We present a pooled update of two large, multicenter MM-009 and MM-010 placebo-controlled randomized phase III trials that included 704 patients and assessed lenalidomide plus dexamethasone versus dexamethasone plus placebo in patients with relapsed/refractory multiple myeloma (MM). Patients in both studies were randomized to receive 25 mg daily oral lenalidomide or identical placebo, plus 40 mg oral dexamethasone. In this pooled analysis, using data up to unblinding (June 2005 for MM-009 and August 2005 for MM-010), treatment with lenalidomide plus dexamethasone significantly improved overall response (60.6 vs 21.9%, P<0.001), complete response rate (15.0 vs 2.0%, P<0.001), time to progression (median of 13.4 vs 4.6 months, P<0.001) and duration of response (median of 15.8 months vs 7 months, P<0.001) compared with dexamethasone-placebo. At a median follow-up of 48 months for surviving patients, using data up to July 2008, a significant benefit in overall survival (median of 38.0 vs 31.6 months, P=0.045) was retained despite 47.6% of patients who were randomized to dexamethasone-placebo receiving lenalidomide-based treatment after disease progression or study unblinding. Low β2-microglobulin and low bone marrow plasmacytosis were associated with longer survival. In conclusion, these data confirm the significant response and survival benefit with lenalidomide and dexamethasone.

PANORAMA 2: panobinostat in combination with bortezomib and dexamethasone in patients with relapsed and bortezomib-refractory myeloma

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.

Lenalidomide plus dexamethasone is more effective than dexamethasone alone in patients with relapsed or refractory multiple myeloma regardless of prior thalidomide exposure

This analysis assessed the efficacy and safety of lenalidomide + dexamethasone in patients with relapsed or refractory multiple myeloma (MM) previously treated with thalidomide. Of 704 patients, 39% were thalidomide exposed. Thalidomide-exposed patients had more prior lines of therapy and longer duration of myeloma than thalidomide-naive patients. Lenalidomide + dexamethasone led to higher overall response rate (ORR), longer time to progression (TTP), and progression-free survival (PFS) versus placebo + dexamethasone despite prior thalidomide exposure. Among lenalidomide + dexamethasone-treated patients, ORR was higher in thalidomide-naive versus thalidomide-exposed patients (P = .04), with longer median TTP (P = .04) and PFS (P = .02). Likewise for dexamethasone alone-treated patients (P = .03 for ORR, P = .03 for TTP, P = .06 for PFS). Prior thalidomide did not affect survival in lenalidomide + dexamethasone-treated patients (36.1 vs 33.3 months, P > .05). Thalidomide-naive and thalidomide-exposed patients had similar toxicities. Lenalidomide + dexamethasone resulted in higher rates of venous thromboembolism, myelosuppression, and infections versus placebo + dexamethasone, independent of prior thalidomide exposure. Lenalido-mide + dexamethasone was superior to placebo + dexamethasone, independent of prior thalidomide exposure. Although prior thalidomide may have contributed to inferior TTP and PFS compared with thalidomide-naive patients, these parameters remained superior compared with placebo + dexamethasone; similar benefits compared with placebo + dexamethasone were not evident for thalidomide-exposed patients in terms of overall survival. Studies were registered at http://www.clinicaltrials.gov under NCT00056160 and NCT00424047.

Clinical course of solitary extramedullary plasmacytoma.

BACKGROUND AND PURPOSE Solitary extramedullary plasmacytoma (EMP) represents a rare category of malignant disease on which there are limited data in regard to diagnosis, staging and natural history. This study attempted to clarify the clinical course of solitary extramedullary plasmacytoma after radiation or surgical therapy given with curative intent. MATERIALS AND METHODS The diagnosis was based on a mass of clonal plasma cells separate from bone or bone marrow without evidence of occult disease elsewhere. Between 1963 and 1996, 22 previously untreated patients with an EMP were diagnosed. Disease presented in the head or neck in 86%, usually in the nasal cavity (NC) or maxillary sinus (MS), and in these areas local bone destruction was found in 10 of 11 patients. Among all patients, serum myeloma protein was present in three patients (14%) and Bence Jones protein alone was found in two patients (9%). Radiation therapy was the sole treatment for 18 of 22 patients, and the median radiotherapy dose was 50 Gy (range, 40-60 Gy); five of seven patients with an EMP of oral cavity (OC), oropharynx (OP), nasopharynx (NP), parotid or larynx also received elective neck irradiation. Two patients underwent surgery plus postoperative irradiation of a plasmacytoma of the sigmoid colon or pleura, and two patients had resection alone of a plasmacytoma of the colon or cervical lymph node. RESULTS Local control was achieved in 21 of 22 patients (95%), and disease never recurred in regional nodes. Disappearance of myeloma protein occurred in three of five patients with an evaluable abnormality. Multiple myeloma developed in seven patients (32%), all within 5 years. The 5-year rate of freedom from progression to multiple myeloma was 56% and the median survival was 9.5 years. CONCLUSION Radiation therapy achieved excellent locoregional control of EMP with an approximate cure fraction of 50%.

Thalidomide and dexamethasone for resistant multiple myeloma

Summary.  Between November 1998 and April 2000, the combination of thalidomide and dexamethasone was evaluated in 47 consecutive patients with multiple myeloma that was resistant to prior high‐dose dexamethasone‐based therapies. Remission was observed in 22 patients (47%), including six patients with complete remission. Side‐effects were frequent, mild and usually reversible, but deep vein thrombosis occurred in 8% of patients. Survival and remission times were longer among patients treated for previous resistant disease rather than for resistant relapse. This experience supports the use of thalidomide–dexamethasone in myeloma patients with resistant disease and justifies further trials in newly diagnosed patients.

Magnetic resonance imaging in the staging of solitary plasmacytoma of bone.

PURPOSE To assess prospectively the role of magnetic resonance (MR) imaging in the staging of patients with a solitary bone plasmacytoma (SBP). PATIENTS AND METHODS Twelve consecutive patients with an apparent SBP underwent MR imaging of both the primary tumor and the thoracic and lumbosacral spine to seek additional foci of marrow involvement that might have been undetected by standard skeletal survey. All patients received megavoltage irradiation (total dose, 40 Gy) to the primary lesion. RESULTS MR imaging of the thoracic and lumbosacral spine showed additional foci of marrow replacement in four of 12 patients, with signal characteristics identical to those of the primary tumor. In all four patients, the abnormal protein persisted at greater than 50% of the pretreatment value following radiation treatment. In contrast, the myeloma protein disappeared or was reduced by greater than 50% in five of the six patients with secretory disease and without additional marrow abnormalities. One of four patients progressed to multiple myeloma 10 months after diagnosis with new lesions on conventional radiographs in the same areas as detected previously by MR imaging. CONCLUSION Four of 12 patients considered to have a SBP by standard criteria may have been understaged, because MR imaging showed additional marrow abnormalities consistent with myeloma. MR imaging of the spine may contribute to the initial staging of SBP, especially since some patients may be cured with radiotherapy.

Clinically relevant end points and new drug approvals for myeloma.

This manuscript summarizes the recommendations of the American Society of Hematology/US Food and Drug Administration Workshop on Clinical Endpoints in Multiple Myeloma, which brought together clinical investigators in multiple myeloma, the United States Food and Drug Administration, pharmaceutical companies, patient advocates and other concerned scientists and physicians to provide guidance, consensus and consistency in the definition of clinically relevant end points to expedite new drug approvals for multiple myeloma in the appropriate trial design settings. This manuscript will therefore be a most valuable resource to provide the framework for the design of appropriate clinical trial strategies for more rapid new drug approval in myeloma.