Bone Effect of Botezomib in Patients with Relapse and Smoldering Myeloma; A Computer Assisted Image Analysis Study of Bone Marrow Core Biopsies,

Bone loss and related complications including bone pains, fractures and hypercalcemia are major causes of morbidity and mortality in multiple myeloma (MM) patients. Bone growth/loss (Bone mineral densitometry) can be monitored by dual x-ray absorptiometry (DXA) in patients with smoldering myeloma (SMM). We previously reported a novel quantitative method to asses trabecular volume (TV) using whole scanned slides and image analysis (WSI) obtained from bone marrow biopsy (Teman et al. 2010). This method provides a low cost reproducible mean to assess TV in archival paraffin embedded biopsy materials. Velcade has been shown to produce an anabolic bone effect in relapsed/refractory MM patients and in this study, we examine the effect of low-dose bortezomib (Velcade) in SMM patients using the WSI methodology.

Bone marrow biopsy slides obtained before, during and after bortezomib treatment were used to evaluate TV. H&E stained core biopsy slides were scanned using Scan Scope XT system (Aperio Technologies, Vista, CA) into digital whole slide images that is viewable on Aperio Image Scope. We developed classifier algorithms using Genie (Aperio) pattern recognition image analysis software (PRIA) that were adept at identifying bone, hematopoietic tissue, and clear glass. The calculated bone area (TV) was represented as a ratio of the total hematopoietic area for each biopsy event. Slides were excluded if the analysis available area was less than 6mm² or could not be classified correctly to the satisfaction of the pathologist

Mixed-effects models were used to compare bone TV/hematopoietic ratios (HR) over time and between the different groups, as well as assess any correlation with that ratio and light chain, B-2-microglobulin, and plasma cell levels. Results were considered statistically significant if p<0.05.

Slides from 253 consecutive biopsies composed the study materials. 45 were excluded due to significant artifacts or small analysis areas (<6mm²). 208 bone marrow biopsies from 43 patients were included in the analysis. The group included 26 maintenance, 12 relapsed, and 5 smoldering patients; The relapsed and maintenance patients received Bortezomib alone or in combination for a minimum of three cycles; smoldering patients received bortezomib as part of a phase 2 study at the weekly dose of 0.7mg/kg. All maintenance and relapsed, patients had previously received bone marrow transplant with a median 68 years of age 29 were male. Median baseline TV/HR was 32.9%for maintenance 29.8% for relapse and 33.1% smoldering groups. A median increment of TV/RH (17%) was observed after Bortezomib treatment in all groups of patients (p<0.0001).

Analysis of bone associated changes after Bortezomib exposure in patients with multiple myeloma by Scan Scope XT demonstrate a post treatment overall gain in bone formation. Monitoring bone indices in patients with multiple myeloma with PRIA may provide a valid tool to assess treatment associated bone effect.

No relevant conflicts of interest to declare.