The Combination of Cyclophosphamide-Bortezomib-Dexamethasone (CYBOR-D) Is a Highly Effective and Well Tolerated Regimen that Produces Rapid and Complete Hematological Response In Patients with AL Amyloidosis

The combination of Cyclophosphamide, Bortezomib, and Dexamethasone (CYBOR-D) is proven to be highly active and effective in multiple myeloma. (Reeder, Leukemia 2009) We aim to evaluate the safety and efficacy of this regimen in a separate plasma cell neoplasm, AL Amyloidosis. The primary endpoint of this study is hematologic response. Complete hematologic response is defined as normalization of the free light chain ratio with no evidence of a monoclonal protein by immunofixation. Partial hematologic response is defined as a 50% reduction in M-spike or absolute light chain level (Gertz Am J Heme 2006).

We report a series of patients with symptomatic AL Amyloidosis who received treatment with a combination of Bortezomib (1.3mg/m² on days 1, 4, 8, and 11 every 28 days or 1.5 mg/m² weekly), Cyclophosphamide (300 mg/m² orally weekly) and Dexamethasone (40 mg weekly). We include patients in this study regardless of autologous bone marrow transplant candidacy or previous treatment history.

Fifteen patients with AL amyloidosis received two to six cycles of CYBOR-D. The treatment history, bone marrow transplant candidacy prior to treatment, hematological response, and status of transplant after therapy are shown in table 1. Of note, 8 (53%) had symptomatic cardiac involvement all of whom had elevated levels of both cardiac biomarkers (Troponin T and B-natriuretic peptide). Complete hematological response occurred in 11 patients (73.3%) with partial hematological response in 3 patients (20.0%). One patient (6.6%) did not achieve a partial response but did receive autologous bone marrow transplant after treatment with CYBOR-D. Median time to response was 2 months. Six patients (40%) had objective evidence of kidney response to therapy with a greater than 50% decrease in proteinuria.

CYBOR-D produces a rapid and complete hematological response in the majority of patients with AL amyloidosis regardless of previous treatment history or bone marrow transplant candidacy. Overall, it is well tolerated with few side effects that included peripheral neuropathy and infectious complications. Two patients originally determined to be not eligible for transplant improved sufficiently on CYBOR-D to become eligible and then went on to receive autologous bone marrow transplant. The retrospective nature and small sample size limit this study, and prospective, randomized studies are needed to further elucidate the role of this regimen in AL amyloidosis.

Stewart:Millennium Pharmaceuticals, Inc.: Honoraria, Research Funding; Celgene: Honoraria. Fonseca:Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding; Genzyme: Consultancy; Onyx: Research Funding; Otsuka: Consultancy; Medtronic: Consultancy.