SRL 172 (killed Mycobacterium vaccae) may augment the efficacy of trastuzumab in metastatic breast cancer patients

Altundag K., Mohamed A., Altundag O., Silay Y., Gunduz E., Demircan K.

MEDICAL HYPOTHESES, vol.64, no.2, pp.248-251, 2005 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 64 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1016/j.mehy.2004.07.016
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.248-251
  • Hacettepe University Affiliated: No


SRL172, non-specific immunological adjuvant downregulates interleukin-4, upregulates interleukin-2 production, switching towards a T-helper-1 response, induces an increase in natural killer cells and activates antigen presenting cells. The human epidermal growth factor receptor 2 gene amplification is frequently observed in a number of primary tumors, suggesting that the overexpression of this growth factor receptor may contribute to transformation and tumorigenesis. Gene amplification occurs in approximately 15-20% of human breast cancers Amplification is associated with aggressive tumor behavior and shortened survival. Trastuzumab, humanized anti-HER-2 antibody targets the HER-2 protein with high affinity. Trastuzumab when used alone or in combination with cytotoxic chemotherapy can induce reasonably durable remissions in a significant percentage of women with metastatic breast cancer whose tumors demonstrate Her-2/neu gene amplification. One of the proposed mechanisms of trastuzumab antitumor action is through antibody dependent cellular cytotoxocity. Pivotal study showed that Trastuzumab + IL-2 resulted in NK cell expansion with enhanced in vitro targeted killing of HER-2-expressing cells. SRL172 by increasing IL-2 production and number of natural killer cells may augment the efficacy of trastuzumab in metastatic breast cancer patients. SRL 172 increases IL-2 production and the number of NK cells in vivo. Based on these data, a clinical trial can be performed to test whether SRL 172 added to trastuzumab is safe and more efficacious. (C) 2004 Elsevier Ltd. All rights reserved.