Quest PharmaTech acquires immunotherapeutic antibody products from Paladin Labs

Quest PharmaTech Inc. (TSX-V: QPT) ("Quest" or the "Company"), a pharmaceutical company developing and commercializing products for the treatment of cancer, today announced that it has acquired a pipeline of late-stage immunotherapy product candidates from Paladin Labs Inc. (TSX:PLB) ("Paladin").

The pipeline of product candidates consists of five monoclonal antibodies targeting certain tumor antigens that are presented in a variety of cancers. The first and most advanced of these product candidates is Oregovomab, an anti-CA125 antibody for the treatment of ovarian cancer patients that Quest will evaluate in combination with front-line chemotherapy.

Quest also acquired anti-MUC1, anti-TAG72, anti-PSA and anti-CA19.9 antibodies that could potentially be used for the treatment of breast, lung, stomach, colorectal, pancreas and prostate cancer.

"We believe that these newly acquired immunotherapeutic antibody products have the opportunity to become significantly more effective when combined with chemotherapy, radioimmuno therapy or photodynamic therapy," said Dr. Madi R. Madiyalakan, Chief Executive Officer for Quest. "As one of the original inventors of this technology, I have a deep understanding of the potential of these compounds to become more efficacious treatments for cancer when used as an adjunct in combination with these established therapies. We intend to expeditiously evaluate the potential of the acquired products for conducting a registration trial for one or more combination therapies, which, if successful, could lead directly to one or more applications for regulatory approval."

As part of the transaction, Paladin receives an upfront payment of $37,500 and 1.5 million common shares of Quest, with an additional 1.5 million common shares to be issued to Paladin on or before December 31, 2010. Paladin may also receive an additional 2.0 million common shares of Quest if the Company is successful in its future financing initiatives. The agreement also provides single-digit royalty payments to Paladin on future revenues. In addition to more than 50 issued patents (including eight issued U.S. patents), Quest will also receive associated Oregovomab documents that could be used as the basis for an ovarian cancer clinical trial application, and other product-related assets that could enable clinical trial conduct.

The immunotherapeutic approach to cancer treatment involves modulating the immune system to achieve a therapeutic goal. This approach has advantages in comparison to current conventional treatment practices, which are often radical in nature and associated with severe toxicities, thereby compromising the patient's quality of life. To date though, attempts to use monoimmunotherapies to elicit a therapeutic benefit have met with mixed results as evidenced recently by the data derived from a Phase III trial evaluating Oregovomab as a treatment for ovarian cancer patients.

However, based on the safety, immunology and efficacy data available from more than 1,000 cancer patients and its in-house expertise, Quest believes that it can make treatment modifications to its new portfolio of oncology product candidates to prolong, amplify and shape anti-tumor immune responses to increase the clinical benefits of these antibodies for the treatment of human cancer.

Based on the following observations attributed to Quest's current product portfolio, the Company is confident that combining antibodies with other cancer therapies such as chemotherapy, photodynamic therapy or radioimmuno therapy can potentially further complement and enhance the treatment outcome compared to antibody treatment alone:

- Combination with chemotherapy: A recent 40-patient randomized clinical trial (Journal of Immunotherapy, 2009, Volume 32, page 54- 65) established that front-line carboplatin-paclitaxel chemotherapy has immune adjuvant properties when administered concurrent to the anti-CA125 antibody, and immunity is enhanced relative to that which is achievable in an antibody treatment alone; - Combination with photodynamic therapy: In recent preclinical studies done at the BC Cancer Agency (Photochemistry and Photobiology, 2009, DOI:1111, European Patent # 1,357,944), Quest showed that the therapeutic outcome of SL052 mediated photodynamic therapy can be improved by a combination with antibody mediated immunotherapy; and - Combination with radioimmuno therapy: The use of Oregovomab, radiolabeled with an appropriate therapeutic isotope, has the potential to provide the benefits of antibody mediated immune response as well as antigen-bearing tumor cell radiotoxicity. Such a concept has already been established in a preclinical setting (Applied Radiation and Isotopes, 1997, Volume 48, pages 899-906).

The combination therapy approach may apply to other tumor antibodies. A Phase I clinical trial with anti-MUC1 antibody in 17 patients with metastatic cancer, including multiple myeloma, demonstrated the activation of humoral and cellular anti-tumor immunity (Annals of Oncology, 2004, Volume 15, pages 1825-1833).

In addition to the antibodies purchased from Paladin, Quest's oncology pipeline includes small molecule prostate cancer product candidate SL052 that is expected to enter the dosing stage of a Phase I clinical trial in the fourth quarter of 2009.

SOURCE Quest PharmaTech Inc.

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