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Combination Therapy with Imprime PGG and Erbitux Doubles Overall Response Rate in Colorectal Cancer Clinical Trial

Final Study Results Released at 35th European Society for Medical Oncology Congress

MILAN--(BUSINESS WIRE)--Oct 12, 2010 - A combination of Biothera's Imprime PGG® and cetuximab (Erbitux®) doubled the overall response rates for second- and third-line metastatic colorectal cancer patients participating in a Phase Ib/IIa clinical trial. The completed trial results were released yesterday at the 35th European Society for Medical Oncology (ESMO) Congress.

The sequential, dual-arm, open-label, dose-escalation study evaluated the safety and efficacy of Imprime PGG plus cetuximab and irinotecan (Arm #1) or Imprime PGG plus cetuximab alone (Arm #2). The 32-patient trial was conducted in Asia. In both arms of the trial, patients were dosed with 2 mg/kg, 4 mg/kg or 6 mg/kg of Imprime PGG in combination with standard doses of cetuximab and irinotecn. Imprime PGG was safe and well tolerated.

All tumor responses and duration of responses were based on Response Evaluation Criteria in Solid Tumors (RECIST), Version 1.0.

Study Arm 1 Results
This portion of the study compared the combination of Imprime PGG, cetuximab and irinotecan to the standard of care of cetuximab and irinotecan alone for these late-stage patients. The trial results from this Arm demonstrated a doubling of the historical overall response rate and a two-month extension in the time to progression of these patients, compared with cetuximab and chemotherapy.

Biothera Colorectal Cancer Phase Ib/IIa Arm #1 Study
Results Compared to Historical Data
                  Chemotherapy +
          Chemotherapy +       Cetuximab +
          Cetuximab*       Imprime PGG**
  Response Rate       16%       30%
  Stable Disease Rate       45%       70%
  Disease Control Rate       61%       100%
  Progression-Free Survival       16 weeks       22 weeks
  Number of patients       648       10
* EPIC Study (Sobrero et al., JCO, 2008)
** Biothera Study

Study Arm 2 Results
This portion of the trial compared the combination of Imprime PGG and cetuximab with cetuximab monotherapy. Chemotherapy was not administrated to avoid the unintentional destruction of immune cells that are integral to Imprime PGG's mechanism of action. The trial results from this Arm demonstrated a doubling of the historical overall response rate and the time to progression of these patients, compared with cetuximab monotherapy.

Biothera Colorectal Cancer Phase Ib/IIa Arm #2 Study
Results Compared to Historical Data
          Cetuximab       Cetuximab +
          Alone*       Imprime PGG
  Response Rate       11%       24%
  Stable Disease Rate       22%       38%
  Disease Control Rate       33%       62%
  Progression-Free Survival       6 weeks       12 weeks
  Number of patients       111       21
* Erbitux (cetuximab) alone data from the BOND study, Cunningham et al., NEJM 2004.

Subpopulation Results
The study also retrospectively looked at subpopulations of the colorectal cancer patients based on those whose tumors expressed wild type versus mutated KRAS genes. In the wild type KRAS patient population responses were even more pronounced as shown below.

Biothera Colorectal Cancer Phase Ib/IIa Arm #2 Study
Results for KRAS Wild Type Patients Compared to Historical Data
          Cetuximab       Cetuximab +
          Alone*       Imprime PGG
  Response Rate       17%       46%
  Stable Disease Rate       49%       36%
  Disease Control Rate       66%       82%
  Progression-Free Survival       11 weeks       24 weeks
  Number of patients       262       11
* Erbitux (cetuximab) alone KRAS wild type data represent the mean of response data reported from 4 published studies (Khambata JCO 2007, DeRook Ann Oncol 2008, Lurje Clin Cancer Res 2008, Karapetis NEJM 2008; Total subjects from all Studies = 262.)

“The results of this dual arm study demonstrate the proof of concept the Imprime PGG is a novel drug that engages and directs innate immune cells to kill cancer,” said Dan Conners, president of Biothera's Pharmaceutical Group. “Imprime PGG's ability to engage the innate immune system opens the door to numerous new therapeutic combinations with monoclonal antibodies targeting the vast majority of cancers.”

About Imprime PGG®
Imprime PGG® is a novel immunotherapy that works synergistically with anti-tumor monoclonal antibodies to activate the largest population of the body's immune cells (neutrophils) to kill cancer cells. Imprime PGG is currently in multiple Phase II clinical trials for lung and colorectal cancer. While some immunomodulatory drugs trigger a broad proinflammatory response, Imprime PGG selectively targets and activates neutrophils without inducing systemic pro-inflammatory cytokines that are attributed to adverse reactions. As a platform therapeutic in oncology, Imprime PGG has the potential to improve patient response rates for existing monoclonal antibody therapies in approved indications, create new indications for these drugs and enhance the efficacy of development-stage monoclonal antibody drugs.

About Biothera, the Immune Health Company
Biothera is a biotechnology company dedicated to improving immune health. The company is developing pharmaceuticals that engage the innate immune system to fight cancer. (www.biothera.com)

Contact: Biothera, the Immune Health Company
David Walsh, 651-256-4606 (direct)
VP Communications
dwalsh@biothera.com

 

Posted: October 2010

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