Neutralizing B-cell activating factor antibody improves survival and inhibits osteoclastogenesis in a severe combined immunodeficient human multiple myeloma model.
OBJECTIVE
B-cell-activating factor (BAFF) is a tumor necrosis factor superfamily member critical for the maintenance and homeostasis of normal B-cell development. It has been implicated in conferring a survival advantage to B-cell malignancies, including multiple myeloma (MM).


METHODS
Here, we validate the role of BAFF in the in vivo pathogenesis of MM examining BAFF and its receptors in the context of patient MM cells and show activity of anti-BAFF antibody in a severe combined immunodeficient model of human MM.


RESULTS
Gene microarrays and flow cytometry studies showed increased transcripts and the presence of all three receptors for BAFF in CD138+ patient MM cells, as well as an increase in plasma BAFF levels in 51 MM patients. Functional studies show that recombinant BAFF protects MM cells against dexamethasone-induced apoptosis accompanied by an increase in survival proteins belonging to the BCL family. These in vitro studies led to the evaluation of a clinical grade-neutralizing antibody to BAFF in a severe combined immunodeficient human MM model. Anti-BAFF-treated animals showed decreased soluble human interleukin 6 receptor levels, a surrogate marker of viable tumor, suggesting direct anti-MM activity. This translated into a survival advantage of 16 days (P < 0.05), a decrease in tartrate-resistant acid phosphatase-positive osteoclasts, and a reduction in radiologically evident lytic lesions in anti-BAFF-treated animals.


CONCLUSIONS
Our data show a role for BAFF as a survival factor in MM. Importantly, the in vivo antitumor activity of neutralizing anti-BAFF antibody provide the preclinical rationale for its evaluation in the treatment of MM.
Neri
Paola
P
Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
Kumar
Shaji
S
Fulciniti
Maria Teresa
MT
Vallet
Sonia
S
Chhetri
Shweta
S
Mukherjee
Sidhartha
S
Tai
Yutzu
Y
Chauhan
Dharminder
D
Tassone
Pierfrancesco
P
Venuta
Salvatore
S
Munshi
Nikhil C
NC
Hideshima
Teru
T
Anderson
Kenneth C
KC
Raje
Noopur
N
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D053264:B-Cell Activating Factor / Q000276:immunology / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival; D020869:Gene Expression Profiling; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D009101:Multiple Myeloma / Q000235:genetics* / Q000276:immunology*; D010010:Osteoclasts / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D000071681:Tartrate-Resistant Acid Phosphatase; D016896:Treatment Outcome
D000906:Antibodies; D053264:B-Cell Activating Factor; D015850:Interleukin-6; D007527:Isoenzymes; D011994:Recombinant Proteins; C505719:TNFSF13B protein, human; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase