[doh2pa]

To John 21,

Actually, there's a new "herceptin" in the works - pertuzumab. It's good to see that researchers are focusing on targeted therapies, as they are generally so much easier to tolerate than traditional chemo. Lani posted the trial recently, - here's a cut and paste on it.

2007 ASCO Annual Meeting


Abstract No:

14149
Citation:

Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings Part I. Vol 25, No. 18S (June 20 Supplement), 2007: 14149
Author(s):

H. Nakajima, S. Tanuma, I. Fujiwara, N. Mizuta, K. Sakaguchi
Abstract:

Background: HER2 is a unique receptor molecule for which no ligand has been found and functions as a coreceptor to form homo-and hetero-dimers with other three HER (1, 3 and 4) family members. The dimerization results in the activation of HER tyrosine kinase. This, in turn, promotes the tyrosine phosphorylation of certain proteins, leading to the stimulation of cell proliferation, invasion, and antiapoptosis. The overexpression of HER2 in breast cancer correlates with increased tumor growth and metastatic potential, and thereby poor long-term survival for the patient. A monoclonal antibody against HER2, named trastuzumab, is approved for breast cancer patients, while pertuzumab is currently in phaseIIclinical trial. The two antibodies bind to different epitopes in the extracellular domains of HER2. Trastuzumab binding mainly mediates the antibody-dependent cytotoxicity (ADCC). On the other hand, pertuzumab binding directly inhibits HER2 dimerization with its partner receptors, blocking the growth signaling and inducing apoptosis. Furthermore, the unique binding pockets on HER2 for trastuzumab and pertuzumab have been resolved and provide the important target domains for creation of new anticancer drugs. Methods: Based on these mechanisms, we are trying to design and create both antibodies-mimetic molecules using our in silico methodologies COSMOS (Conversion to small molecules through optimized-peptide strategy) and SARM (Self-assembling regulatory molecule). We design HRAP (HER2 reactive peptide)- SARM and HRAP- SARM- FAB (Fc?-binding peptide). HRAP-SARM may bind to HER2 pertuzumab binding site and sterically interferes with HER2 dimerization and induces apoptosis. HRAP- SARM- FAB is expected to induce both ADCC and apoptosis. Results and Conclusion: In this presentation, we will show the preliminary results and functions of the Ab-mimetics, HRAP-SARM and HRAP- SARM- FAB on human breast cancer cells overexpressing HER2, as compared to those of trastuzumab and pertuzumab. Since those Ab-mimetics are small molecules and cheap, the successful results are sure to promise the revolutionary therapy for refractory breast cancer