||This article needs attention from an expert on the subject. (May 2009)|
|Mol. mass||145.3 kDa|
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Mechanism of action
Bavituximab binds to phosphatidylserine which is exposed on the surface of certain atypical animal cells, including tumour cells and cells infected with any of six different families of virus. These viral families contain the viruses hepatitis C, influenza A and B, HIV 1 and 2, measles, respiratory syncytial virus and pichinde virus, which is a model for the deadly Lassa virus. Other cells are not affected since phosphatidylserine normally is only intracellular.
These target aminophospholipids, usually residing only on the inner leaflet of the plasma membrane of cells, become exposed in virally infected, damaged or malignant cells, and more generally in most cells undergoing the process of apoptosis.
The antibody's binding to phospholipids alerts the body’s immune system to attack the tumor endothelial cells, thrombosing the tumor's vascular network and/or attacking free floating virally infected and metastatic cells while potentially minimizing side effects in healthy tissues.
A phase IIB registrational trial in 2nd line lung cancer showed doubling of MOS (median overall survival) over soc. 11.7 months for 3mg/kg group. HR 0.73 A phase II trial in frontline lung cancer is awaiting results as of 5/13 A phase II trial in pancreatic cancer showed an increase survival benefit of 2 weeks and a very impressive doubling of ORR and HR 0.75 A phase II trial of bavituximab used with docetaxel against advanced breast cancer has yielded median progression-free survival (PFS) data of 7.4 months, a best overall response rate of 61% (28 of 46 patients) with 11% (5 of 46) of the patients achieving a clinical complete response. (This compares favorably to a separately published study of a similar patient population receiving docetaxel alone, which showed an objective response rate of only 41% with no complete responses. Median overall survival figures are not yet available.
A phase II trial of bavituximab used with paclitaxel and carboplatin chemotherapy against advanced breast cancer has yielded median progression-free survival (PFS) data of 6.9 months, a best overall response rate of 74% (34 of 46 patients) with 9% (4 of 46) of the patients achieving a clinical complete response. (This compares favorably to a separately published study of a similar patient population receiving paclitaxel and carboplatin alone, which showed a median PFS of 4.8 months, an objective response rate of 62%.) Median overall survival figures are not yet available. 
Another phase II study of bavituximab plus paclitaxel and carboplatin is being conducted in untreated locally advanced or metastatic non-small cell lung cancer.
Other monoclonal antibodies targeting phospholipids
- Statement on a nonproprietary name adopted by the USAN council
- Nature Medicine 14, 1357 - 1362 (2008)
- He, J.; Yin, Y.; Luster, T. A.; Watkins, L.; Thorpe, P. E. (2009). "Antiphosphatidylserine Antibody Combined with Irradiation Damages Tumor Blood Vessels and Induces Tumor Immunity in a Rat Model of Glioblastoma". Clinical Cancer Research 15 (22): 6871–6880. doi:10.1158/1078-0432.CCR-09-1499. PMID 19887482.
- New Progression-Free Survival Data From Peregrine's Bavituximab in Phase II Refractory Breast Cancer
- Phase II Advanced Breast Cancer Data to Be Presented at ASCO Highlight Promising Tumor Response and Progression-Free Survival Data With Peregrine's Bavituximab
- Pharma company completes humanization of 3G4 antibody
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- Ran; Downes, A.; Thorpe, P. E. (2002). "Increased exposure of anionic phospholipids on the surface of tumor blood vessels". Cancer Research 62 (21): 6132–6140. PMID 12414638.
- Soares M, Syed S, Barbero G, Thorpe PE (April 2007). "Antibody-mediated targeting of "inside-out" anionic phospholipids in viral disease". J Immunol 178 (Meeting Abstracts): 47.21.
- Nature Medicine, V14, p1357.