Laumann, Kristina

Key PointsWe identified CRBN-binding proteins and confirmed recent work implicating the Ikaros transcription factors as important members. Low IZKF1 levels predict lack of IMiD responsiveness and shorter OS; IZKF1 expression is a potential predictive biomarker for clinic application.

Abstract Light-chain (AL) amyloidosis remains incurable despite recent therapeutic advances. Given the activity of the lenalidomide-alkylating agent combination in myeloma, we designed this phase 2 trial of lenalidomide, cyclophosphamide, and dexamethasone in AL amyloidosis. Thirty-five patients, including 24 previously untreated, were enrolled. Nearly one-half of the patients had cardiac stage III disease and 28% had ≥ 3 organs involved. The overall hematologic response (≥ partial response [PR]) rate was 60%, including 40% with very-good partial response or better. Using serum-free light chain for assessing response, 77% of patients had a hematologic response. Organ responses were seen in 29% of patients and were limited to those with a hematologic response. The median hematologic progression-free survival was 28.3 months, and the median overall survival was 37.8 months. Hematologic toxicity was the predominant adverse event, followed by fatigue, edema, and gastrointestinal symptoms. A grade 3 or higher toxicity occurred in 26 patients (74%) including ≥ grade 3 hematologic toxicity in 16 patients (46%) and ≥ grade 3 nonhematologic toxicity in 25 patients (71%). Seven patients (20%) died on study, primarily because of advanced disease. Lenalidomide, cyclophosphamide, and dexamethasone (CRd) is an effective combination for treatment of AL amyloidosis and leads to durable hematologic responses as well as organ responses with manageable toxicity. The trial was registered at www.clinicaltrials.gov (NCT00564889).

Abstract Immunoglobulin light-chain (AL) amyloidosis is a rare, incurable plasma cell disorder. Its therapy has benefited immensely from the expanding drug armamentarium available for multiple myeloma. Pomalidomide in combination with weekly dexamethasone (Pom/dex) is active among patients with relapsed myeloma. In the present study, we explored the Pom/dex combination in patients with previously treated AL. Patients were eligible for this prospective phase 2 trial if they had had at least one prior regimen and if they had reasonably preserved organ function. Patients were treated with oral Pom/dex. Thirty-three patients were enrolled. The median age was 66 years. Median time from diagnosis to on-study was 37 months. Eighty-two percent had cardiac involvement. The confirmed hematologic response rate was 48%, with a median time to response of 1.9 months. Organ improvement was documented in 5 patients. The median overall and progression-free survival rates were 28 and 14 months, respectively; the 1-year overall and progression-free survival rates were 76% and 59%, respectively. There was a discordance between the hematologic response and the N-terminal pro-brain natriuretic peptide response. The most common grade 3-5 adverse events, regardless of attribution, were neutropenia and fatigue. We conclude that pomalidomide appears to be a valuable drug covering an unmet clinical need in patients with previously treated AL. The trial is registered at www.clinicaltrials.gov as NCT00558896.

Purpose Cardiac involvement predicts poor prognosis in light chain (AL) amyloidosis, and the current prognostic classification is based on cardiac biomarkers troponin-T (cTnT) and N-terminal pro–B-type natriuretic peptide (NT-ProBNP). However, long-term outcome is dependent on the underlying plasma cell clone, and incorporation of clonal characteristics may allow for better risk stratification. Patients and Methods We developed a prognostic model based on 810 patients with newly diagnosed AL amyloidosis, which was further examined in two other datasets: 303 patients undergoing stem-cell transplantation, and 103 patients enrolled onto different clinical trials. Results We examined the prognostic value of plasma cell–related characteristics (ie, difference between involved and uninvolved light chain [FLC-diff], marrow plasma cell percentage, circulating plasma cells, plasma cell labeling index, and β 2 microglobulin). In a multivariate model that included these characteristics as well as cTnT and NT-ProBNP, only FLC-diff, cTnT, and NT-ProBNP were independently prognostic for overall survival (OS). Patients were assigned a score of 1 for each of FLC-diff ≥ 18 mg/dL, cTnT ≥ 0.025 ng/mL, and NT-ProBNP ≥ 1,800 pg/mL, creating stages I to IV with scores of 0 to 3 points, respectively. The proportions of patients with stages I, II, III and IV disease were 189 (25%), 206 (27%), 186 (25%) and 177 (23%), and their median OS from diagnosis was 94.1, 40.3, 14, and 5.8 months, respectively (P < .001). This classification system was validated in the other datasets. Conclusion Incorporation of serum FLC-diff into the current staging system improves risk stratification for patients with AL amyloidosis and will help develop risk-adapted therapies for AL amyloidosis.

Abstract Pomalidomide at doses of 2 or 4 mg/d has demonstrated excellent activity in patients with multiple myeloma (MM). We opened 2 sequential phase 2 trials using the pomalidomide with weekly dexamethasone (Pom/dex) regimen at differing doses to study the efficacy of this regimen in patients who have failed both lenalidomide and bortezomib. Pomalidomide was given orally 2 or 4 mg daily with dexamethasone 40 mg weekly. Thirty-five patients were enrolled in each cohort. Confirmed responses in the 2-mg cohort consisted of very good partial response (VGPR) in 5 (14%), partial response (PR) in 4 (11%), minor response (MR) in 8 (23%) for an overall response rate of 49%. In the 4-mg cohort, confirmed responses consisted of complete response (CR) in 1 (3%), VGPR in 3 (9%), PR in 6 (17%), MR in 5 (14%) for an overall response rate of 43%. Overall survival at 6 months is 78% and 67% in the 2- and 4-mg cohort, respectively. Myelosuppression was the most common toxicity. This nonrandomized data suggests no advantage for 4 mg over the 2 mg daily. Pomalidomide overcomes resistance in myeloma refractory to both lenalidomide and bortezomib. This trial is registered at http://ClinicalTrials.gov, number NCT00558896.

Purpose Thalidomide and lenalidomide are immunomodulatory drugs (IMiDs) that produce high remission rates in the treatment of multiple myeloma. Pomalidomide is a new IMiD with high in vitro potency. We report, to our knowledge, the first phase II trial of pomalidomide administered in combination with low-dose dexamethasone for the treatment of relapsed or refractory multiple myeloma. Patients and Methods Pomalidomide was administered orally at a dose of 2 mg daily on days 1 through 28 of a 28-day cycle. Dexamethasone 40 mg daily was administered orally on days 1, 8, 15, and 22 of each cycle. Responses were recorded using the criteria of the International Myeloma Working Group. Results Sixty patients were enrolled. Thirty-eight patients (63%) achieved confirmed response including complete response in three patients (5%), very good partial response in 17 patients (28%), and partial response in 18 patients (30%). Responses were seen in 40% of lenalidomide-refractory patients, 37% of thalidomide-refractory patients, and 60% of bortezomib-refractory patients. Responses were seen in 74% of patients with high-risk cytogenetic or molecular markers. Toxicity consisted primarily of myelosuppression. Grade 3 or 4 hematologic toxicity consisted of anemia (5%), thrombocytopenia (3%), and neutropenia (32%). One patient (1.6%) had a thromboembolic event. The median progression-free survival time was 11.6 months and was not significantly different in patients with high-risk disease compared with patients with standard-risk disease. Conclusion The combination of pomalidomide and low-dose dexamethasone is extremely active in the treatment of relapsed multiple myeloma, including high response rates in patients refractory to other novel agents.