Administration of anti‐TGFβ (1D11) prevented rTGFβ inhibition of osteoblastic alkaline phosphatase production and mineralization in vitro and resulted in a substantial bone anabolic effect in vivo. (A) Alp production in primary murine Ob‐LC cultured in osteogenic media with vehicle (CTRL), rTGFβ and IC antibody (rTGFβ + IC), or rTGFβ and 1D11 antibody (rTGFβ + 1D11) for 7 (i) and 14 days (ii). Alp production in SAOS‐2 cells cultured in standard media and treated as above for 3 days (iii). Mineralization in Ob‐LC treated as above for 14 (iv) and 21 days (v). Representative images of mineralization in Ob‐LC treated as above (vi). All data are representative from four independent experiments, presented as mean fold change ± SD, one‐way ANOVA, **p ≤ 0.01, ***p ≤ 0.001, and ****p ≤ 0.0001. (B) Schematic demonstrating the treatment schedule for 1D11 monotherapy treatment in Naïve mice and the JJN3 model of myeloma. (C) Representative 3D trabecular μCT images from the tibias of Naïve + IC (i), Naïve + 1D11 (ii), JJN3 + IC (iii), and JJN3 + 1D11 (iv) mice. BV/TV (v), trabecular number (vi), and trabecular thickness (vii) analyzed in the tibias by μCT. All data are presented as mean ± SD, Student's t test, **p ≤ 0.001 and ***p ≤ 0.001.