British-based BTG received more good news this week regarding Campath after its licensee, Genzyme Corp, and Bayer Schering Pharma AG announced they had kicked off a Phase III trial testing the drug’s efficacy in multiple sclerosis.

Genzyme and Bayer’s CARE-MS I trial (Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis), is designed to pit Campath against Merck Serono’s Rebif (interferon beta-1a) in patients with relapsing-remitting MS, who have not yet begun any treatment. CARE-MS II, which is scheduled to start shortly, will enroll patients who have continued to experience relapse episodes while on currently available disease-modifying therapies.

CARE-MS I will enroll up to 525 patients at around 60 medical centres throughout North America, Australia, Latin America, and Europe, and will compare the effect of Campath and Rebif on the time to sustained accumulation of disability and the annualised relapse rate.

Campath is a humanized monoclonal antibody that binds to a specific target - CD52 - on cell surfaces, and thereby triggers an immune response to destroy these cells. Through a series of company acquisitions, Genzyme acquired the worldwide rights to Campath from BTG back in 2001, and the UK group stands to gain royalties from any indications the drug gains approval for.

Growing royalties

Last year, BTG earned gross royalties of £4.5 million on $120 million worth of sales of Campath as a third-line treatment for B-cell chronic lymphocytic leukaemia, but this figure could grow substantially after the agent won approval for first-line use last week, a company spokesperson told PharmaTimes.

And the company is very excited about the drug’s potential in MS, which, the spokesperson pointed out, currently has a market of around $4.5 billion, and is lead by Rebif.

“We are excited by the prospects of Campath in multiple sclerosis...If the excellent results from the phase II trials are reproduced, patients will have a new treatment option that has the potential to be much more efficacious than any other existing treatment,” commented BTG’s chief executive Louise Makin.

The companies anticipate filing Campath for the treatment of MS in 2011 and, according BTG’s spokesperson, there is no reason why the drug should not be of “blockbuster magnitude” if it proves to be as effective as Rebif.

BTG shares climbed nearly 5% yesterday to 101.00 pence on the London Stock Exchange.