Azaspirane inhibits in vivo human MM cell growth in a SCID mouse model. CB-17 SCID mice were inoculated subcutaneously in the interscapular area with 5 × 10⁶ OPM1 MM cells. Three weeks later with detection of palpable tumors, mice were treated intravenously with azaspirane (50 mg/kg per day) or vehicle control (PBS) for 6 days. Tumor volume was calculated as described in “Materials and methods.” Figure demonstrates significant tumor regression at 3 to 6 days following treatment. Error bars represent ± SD of tumor volume.