New Ovarian Cancer Drug now available - Avastin

Avastin (Bevacizumab) is a monoclonal antibody that targets VEGF, a protein that plays a key role in the development of new blood vessels. In March 2012 it received TGA approval to be given in patients with newly diagnosed, advanced ovarian cancer (first line treatment) in Australia. Avastin is not registered to treat patients who develop a recurrence of their ovarian cancer.

Formation of new blood vessels is a prerequisite for malignant tumours to grow and to spread. VEGF is a substance produced by tumours that stimulates blood vessel growth. Avastin blocks VEGF and blood vessel formation. While Avastin has some anti-cancer activity in itself, it is more effective in combination with chemotherapy.

Two randomised trials are available on Avastin. One study is from the U.S. GOG and the other study is a European study. Both trials showed almost identical results. There was a statistically improved time to disease progression by 4 months but that improvement did not translate into an improvement in survival.

Avastin is given as an i.v. infusion at a dose of 15 mg/kg of body weight once every 3 weeks in combination with carboplatin and paclitaxel for up to 6 cycles of treatment. Then it is recommended that treatment is continued as a single agent for a total of 15 months or until disease progression.

Costs: Avastin is currently not reimbursed by Medicare; for patients it is worth approaching private health funds for reimbursement as they reimburse patients in other indications such as bowel cancer. The costs will also depend on the patient’s body weight because the dose follows the body weight. For a 70 kg person, I estimate that Avastin will cost approximately $5,000 per course. Roche has introduced a capping program whereby a yearly cost limit is placed on Avastin: Paients whose dose exceeds 10,000 mg of Avastin (approximately $43,000), will receive Avastin free of charge for the remainder of the 12-motnh period.

Precautions: Avastin blocks blood vessel growth, which is needed for wound repair after surgery. Serious but rare complications of Avastin include bowel perforation and blood clots. Therefore Avastin must not be taken 4 weeks before and after planned surgery.

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