OncoGel™ for oesophageal and brain cancer
OncoGel™ fact sheet
OncoGel™ is a novel intratumoural injectable formulation of paclitaxel, an established chemotherapeutic for the treatment of solid tumours. OncoGel™ is designed to release paclitaxel into the tumour continuously, over four to six weeks, to achieve a far greater concentration of paclitaxel in the tumour compared to that achieved when administered intravenously at the maximum tolerated dose. Additionally, only low systemic levels of paclitaxel are observed, minimising systemic side effects. OncoGel™ is in phase 2a development for the treatment of dysphagia (difficulty in swallowing) in patients suffering from oesophageal cancer and a phase 1/2 study in brain cancer (glioblastoma multiforme) was started in March 2007.
We estimate the global market opportunity in both the oesophageal and brain cancer indications to be around $333 million per annum. We intend to develop OncoGel™ through to market approval in North America and Mexico in at least one indication. The product has been out-licensed to Diatos S.A., a French biopharmaceutical company, outside of these countries, excluding North and South Korea, where it has been out-licensed to Samyang Genex Corporation. We are entitled to development related milestone payments and royalties on potential sales of OncoGel™ in these countries.
Oesophageal Cancer
The American Cancer Society has estimated that around 15,000 new cases of oesophageal cancer are reported in the US each year and the majority of patients with oesophageal cancer present with dysphagia. As a result more than 50 per cent of patients suffer weight loss as they are unable to eat properly, severely impacting on their quality of life. A major goal of current therapy is therefore to reduce dysphagia and palliative treatment may be obtained in individual cases with various combinations of surgery, chemotherapy, radiation therapy, endoscopically inserted stents, photodynamic therapy, and endoscopically-guided photolaser ablation. Despite current therapy, we believe there remains an unmet need for a more effective therapy.
Data from a phase 2a study in Europe and the US, where OncoGel™ was given in conjunction with external beam radiation, found 80 per cent of patients had a clinically meaningful reduction in their dysphagia score and 70 per cent had a reduction in tumour volume, with an average reduction of 47 per cent. Biopsies were also found to be negative for carcinoma in four patients and one additional patient had a successful surgical resection. We plan to undertake a randomised, multi-centre phase 2b study of OncoGel™ in combination with chemotherapy in oesophageal cancer patients in the second half of 2007.
We estimate that the potential market for oesophageal cancer is worth up to $145m per annum in the US alone, based on treating the total US population of approximately 14,500 cases with a product priced at $10,000 per patient.
Brain cancer
We also intend to develop OncoGel™ for the treatment of primary brain cancers, such as glioblastoma multiforme (‘‘GBM’’), either post-surgery, by injecting OncoGel™ into the tumour cavity to try to kill residual tumour cells, or directly into the tumour in patients with inoperable tumours.
About 19,000 cases of primary brain cancer are diagnosed in the US each year, of which the majority (60 per cent) are the most malignant form, glioblastoma multiforme (GBM). Treating brain cancer is extremely challenging due to the inability of most chemotherapeutic agents to cross the blood-brain barrier. Where feasible, the primary therapy for patients with primary brain tumours is surgical debulking.
OncoGel™ has demonstrated encouraging dose dependent activity in non-clinical models of brain cancer. A phase 1/2 study is investigating the safety and tolerability of OncoGel™ administered into the cavity produced from the surgical removal of the tumour. The open-label, multi-centre, dose escalation study is being conducted at four centres in the US and will enrol up to 36 patients who have recurrent glioma for which surgical removal of >95% of the tumour is planned. The study will specifically investigate any adverse changes in neurological performance or other side effects that might be related to intracranial OncoGel™ administration at up to six different dose levels.
We have completed recruitment of patients into the first dose cohort. The Data Safety Monitoring Board has considered data from the first cohort of three patients, which includes serious adverse events that may be related to treatment with OncoGel, and has recommended continuing the study with a modified protocol; further recruitment into the study is pending agreement with FDA. Data from this study will determine the dose to be used in future studies of patients with primary or recurrent GBM. Protherics expects to have preliminary data available from the first dose cohort in the second half of 2007 and data from all patients at the end of 2008.
We estimate that the potential market in brain cancer is worth up to $188 million per annum in the US alone, based on treating the total US population of nearly 19,000 patients with a product priced at $10,000 per treatment, where patients could receive repeated treatment with OncoGel™.
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