TG20 has enhanced antibody-dependent cell-mediated cytotoxicity (ADCC), a key feature useful in the treatment of cancer and auto-immune diseases, and it has been shown to have 10-fold enhanced ADCC when compared side by side with rituximab in assays performed with B-cell chronic lymphocytic leukaemia, or B-CLL, patient cancer cell isolates.

“This result is an important demonstration of the ability of GTC’s transgenic technology platform to produce monoclonal antibodies with significantly enhanced ADCC”, said Mr Geoffrey Cox, Chairman, President and CEO of GTC Biotherapeutics. “Furthermore, this is a critical milestone in our development of TG20, an antibody that has the potential of providing more efficacious and cost-effective treatments for cancers such as non-Hodgkin’s lymphoma as well as auto-immune diseases such as rheumatoid arthritis.”

Under their joint venture, GTC and LFB are developing TG20, a MAb that targets the CD20 receptor of the immune system with target specificity similar to the rituximab MAb (Rituxan, MabThera; co-marketed by Biogen Idec and Roche’s Genentech in the US and by Roche in Canada and the EU). This antibody has demonstrated a significantly higher ADCC than rituximab. ADCC is one of the mechanisms that the immune system uses to kill cells targeted by a specific antibody. Therapeutic MAbs with increased ADCC are believed to offer more potent treatments for oncology indications. Rituximab is used as a single-agent treatment for relapsed or refractory indolent non-Hodgkin’s lymphoma, or NHL, and also in combination with chemotherapy for the treatment of aggressive NHL. Rituximab has received marketing approval in both the EU and the US for rheumatoid arthritis. Worldwide sales of rituximab were approximately US$5.6 billion in 2009.

In addition to TG20, GTC is also developing a portfolio of MAbs for use as follow-on biologics. The portfolio includes antibodies targeting HER2, EGFR and TNF, which, together with TG20, address markets with current aggregate sales in excess of US$16 billion. Production animals for these follow-on biologics programmes are in development, and are already established for the HER2 monoclonal antibody. In 2010, GTC plans to characterise each of these transgenically derived antibodies as they become available and to initiate non-clinical studies.

Reference:

GTC Provides Update on TG20 Monoclonal Antibody Targeting CD20. GTC Biotherapeutics Press Release. 2010 March 1.