Meyer, Ralph M.

Abstract Introduction: The NCIC CTG previously reported the results of a dose-finding trial testing the combination of Melphalan (M) and Lenalidomide (L) in previously untreated patients with multiple myeloma who were ineligible for stem cell transplantation because of older age and/or comorbidity (White, Blood2007; 110: 63a). Using a 28-day schedule, M (dose indicated as mg/m2/day given on days 1–4) and L (dose indicated in mg/day given on days 1–21) was associated with excess toxicity with the regimens M9L10, M4L15 and M6L10. We concluded that phase II testing of M5L10 was warranted and now report the results of this testing. Methods: Previously untreated symptomatic and consenting patients with tissue-confirmed plasmacytosis and a measurable M-protein were eligible provided that they had acceptable hematologic and biochemical laboratory parameters and no precluding comorbidities. Planned treatment consisted of M 5 mg/m2 days 1–4 and L 10 mg days 1–21, given every 28 days for 12 cycles. As our intent was to determine dose levels that could be given independently of G-CSF, primary prophylaxis with G-CSF was not included but use of G-CSF for established neutropenia was permitted. A hematologic dose limiting toxicity (H-DLT) was defined as the need for 2 dose attenuations of L or 1 dose attenuation of M occurring within the first 3 treatment cycles. Responses to treatment were classified using 1998 EBMT criteria and assessed after 2 and 6 cycles of therapy. Results: The intended sample size was 41 patients; 35 patients (1 ineligible) were enrolled before the study was closed due to observing a frequency of DLTs that surpassed predefined boundaries. Of the 34 eligible patients, median age was 73.4 yrs and ISS was stage I = 13, stage II = 11 and stage III = 10. Prior to study closure, 27 patients were evaluable for DLT; 7 (26%) did not experience a DLT. Among the remaining 20 (74%) patients, non-hematologic (N=2) and hematologic (N=18) DLTs requiring dose attenuations were seen within the first 3 treatment cycles; the H-DLTs included severe or prolonged neutropenia (N=11), thrombocytopenia (N=2) or both (N=5). One fatal serious adverse event was observed, this was due to a stroke. The other non-hematologic DLT was a cranial nerve III palsy which subsequently resolved. Responses after 2 cycles were evaluable in 21 patients and included partial response (PR) = 11, minimal response = 6, no change = 2 and progressive disease (PD) = 2. For those patients without PD after 2 cycles, responses after 6 cycles were evaluable in 8 and included PR = 6, stable response = 1 and PD = 1. Conclusion: Although M + L is an active combination for previously untreated myeloma patients, the regimen is associated with considerable myelosuppression. Without the routine use of GCSF, the doses used in the MY.11 study were not tolerable. Inability to use planned doses may have compromised the efficacy of the combination.

Abstract Introduction. The NCIC CTG is conducting phase II testing to establish the tolerability and estimate the efficacy of combining lenalidomide (L) + melphalan (M) over multiple cycles for previously untreated patients with multiple myeloma who are ineligible for stem cell transplantation. We report the data from the preliminary safety phase of this trial. Methods. The MY.11 trial was initially designed as a randomized phase II test of M 9 mg/m2 given on days 1–4 (M9) plus either L 10 mg (L10) or 20 mg given on days 1–21 of a 28 day cycle. Primary prophylaxis with G-CSF was not included, but use of G-CSF for established neutropenia was permitted; our intent was to determine dose levels that could be given independently of G-CSF. A dose attenuation schedule was developed for neutropenia and/or thrombocytopenia that was severe and occurred during the administration of L or was persistent and caused a delay in the next treatment cycle. A hematologic dose limiting toxicity (H-DLT) was defined as the need for 2 dose attenuations of L or 1 dose attenuation of M. Prior to the randomized phase of the trial, a safety run-in phase testing M9+L10 in 6 patients was planned; closure of this arm was to occur if, during the first 3 treatment cycles, there were ≥ 3 H-DLTs or any non-hematologic serious adverse event (SAE) judged to be treatment related. Four of the planned 6 patients were entered; during their first 3 treatment cycles, each experienced a H-DLT and one died from sepsis. The study was therefore amended with the intent to conduct a randomized phase II test of M 4 mg/m2 days 1–4 plus L 15 mg days 1–21 (M4L15) and M 6 mg/m2 days 1–4 plus L 10 mg days 1–21 (M6L10). Prior to the randomized phase of testing, each regimen was tested in non-randomized safety run-ins that included 6 patients per arm. The same parameters as above for study arm closure were applied. If the M6L10 arm was closed, the trial would proceed to test M 5 mg/m2 days 1–4 and L 10 mg days 1–21 (M5L10). Results. Six patients were enrolled to M4L15: during their first 3 treatment cycles, 4 patients experienced H-DLTs related to severe or persistent grade 3–4 neutropenia and one other patient experienced an SAE related to hallucinations and multiple constitutional complaints. This arm was therefore closed to accrual. Six patients were enrolled to M6L10: during their first 3 treatment cycles, 3 patients experienced H-DLTs related to severe or persistent grade 3–4 neutropenia. One of these patients was hospitalized with pulmonary edema and another with febrile neutropenia. This arm was therefore closed and the MY.11 trial amended to proceed as a single-arm phase II testing M5L10. Conclusion. Although M + L holds promise as an effective combination for previously untreated myeloma patients, the regimen is associated with considerable myelosuppression. The efficacy of the combination when given at tolerable doses remains to be established.

Abstract Abstract 39 Three randomized trials have previously reported a progression-free survival (PFS) advantage for patients receiving thalidomide (T) maintenance post ASCT in MM. Two trials reported an overall survival (OS) advantage but the largest trial reported shows no OS advantage and in very high risk MM the use of T was deleterious. Recent trial reports demonstrate a PFS but not yet an OS advantage for patients receiving maintenance lenalidomide. We report results of NCIC CTG MY.10 which compared treatment with T (200 mg daily) and prednisone (50 mg alternate days) (T/P) until progression versus observation alone when used as maintenance therapy following ASCT. Importantly, OS was the 1ry endpoint of this study, 2ry endpoints were PFS, quality of life (QoL), toxicity, and the incidence of venous thromboembolism events (VTE). Eligibility: Patients with MM who had ASCT within 1 year of beginning initial treatment for their disease. Patients were randomized 60–100 days post ASCT and had no other medical condition precluding long term use of T/P. Results: 332 patients were enrolled. Median age was 58 years and the arms were balanced. Patients were stratified by age (<60 or >60), and CR status post transplant. Median follow up is 4 years. Only 14% of patients were in CR post transplant. 111 patients died (50 versus 61 in T/P vs. observation). The median OS was 5 years for observation, and has not yet been reached for T/P, however T/P maintenance therapy did not significantly prolong OS: p = 0.18, HR of maintenance vs. observation 0.77 (95% CI 0.53–1.13). The 4 year survival rate was 68% for T/P and 60% for observation. Age and response to transplant had no significant association with OS (p=0.21), while higher disease stage was associated with shorter OS (p=0.03). The median PFS was 28 months for T/P versus 17 months for observation: p<0.0001, HR of T/P vs. observation 0.56 (95% CI 0.43 – 0.73). The 4 year PFS rate was 32% for T/P treated patients versus 14% for patients on observation. At relapse, treatment by arm (T/P vs observation) included lenalidomide (39 vs 34%), T (13 vs 22%) or bortezomib (50 versus 46%). Non hematologic toxicities were seen in more patients with treatment (Grade 3: 92% T/P vs 49% observation, grade 4: 16% vs 7%). Common toxicities of all grades that were significantly higher in T/P treated patients included hyperglycemia, edema, hypertension, fatigue, Cushingoid appearance, constipation, mouth dryness, dyspepsia, anxiety, memory loss, sensory neuropathy, tremor, blurred vision, depressed consciousness, cataracts, dyspnea and bruising. 7% of patients on maintenance T/P developed a VTE in the absence of prophylaxis versus 0% on observation. NCIC CTG standardized response analysis was use to compare QoL data between the 2 treatment arms. Overall, patients on T/P had worse QoL specifically in physical (p=0.07), role (p=0.08), cognitive (p = 0.01) and global (p=0.06) domains, and worse symptoms with dyspnea (p = 0.0007), constipation (p<0.0001), thirst (p=0.003), swelling in leg (p=0.03), numbness (p=0.02), dry mouth (p<0.0001), and balance problems (p<0.0001). However, patients on T/P reported improvement in appetite (p 0.02), and sleep (p=0.04). Conclusions: T/P maintenance did not improve overall survival, the primary objective of this trial, although a trend in favor of T/P was seen. In contrast, PFS was significantly improved in the T/P arm while toxicity was demonstrably increased and quality of life diminished. Disclosures: Stewart: Millennium: Consultancy; Celgene: Honoraria. Trudel:Celgene: Honoraria. Bahlis:Celgene: Honoraria, Research Funding, Speakers Bureau. White:Celgene: Honoraria, Research Funding. Meyer:Celgene: Honoraria.

SummaryVenous thromboembolism (VTE) has an increased incidence in patients with multiple myeloma (MM), especially during chemotherapy. Mechanisms including upregulation of procoagulant factors, such as factor VIII, have been postulated. The National Cancer Institute of Canada Clinical Trials Group MY.10 phase III clinical trial compared thalidomide‐prednisone to observation for 332 patients with MM post‐autologous stem cell transplantation (ASCT), with a primary endpoint of overall survival and various secondary endpoints including the incidence of VTE. One hundred and fifty‐three patients had biomarker data, including D‐dimer, factor VIII and thrombin anti‐thrombin (TAT) levels collected post‐ASCT at baseline and 2 months after intervention investigating in‐vivo thrombin generation. Differences between the time‐points included a significant reduction over time in D‐dimer, factor VIII and TAT levels in the observation group and sustained elevation of D‐dimer, significant increase in factor VIII and reduction in TAT levels in the thalidomide‐prednisone group. Eight VTE events were reported in this subset of study patients, all in the thalidomide‐prednisone arm, with a trend to increase in D‐dimer levels over time in those patients with VTE. This study provides physiological and clinical evidence for an increased risk of VTE associated with thalidomide‐prednisone maintenance therapy post‐ASCT for MM.

Key Points Thalidomide and prednisone maintenance after transplantation improves progression-free but not overall survival.