US-based drug company Pharmion has bought Cabrellis Pharmaceuticals (formerly Conforma Therapeutics in a transaction, valued at up to $104 million, that gives it rights to amrubicin, a new cancer drug due to be filed for approval in 2009.

The deal includes an upfront payment of $59 million, with milestones of $12.5 million apiece if amrubicin secures approval in the USA and EU. A further $10 million will be payable if the drug is cleared for a second indication in each market.

Amrubicin, described as a third-generation anthracycline, is already on the market in Japan for both small cell and non-small cell lung cancer. It is sold there by Nippon Kayaku as Calsed under license from its original developer Dainippon Sumitomo Pharmaceuticals.

Conforma licensed North American and EU rights to the drug in June 2005, but is was not included in the deal when Biogen-Idec bought all other elements of the business in May. Cabrelis was formed exclusively to focus on amrubicin's development.

Anthracyclines are widely used in cancer, but the currently-approved agents – such as doxorubicin, daunorubicin and epirubicin – are closely related molecules that share a tendency to cause cardiotoxicity as a side effect.

While these are derived semi-synthetically from a natural compound, amrubicin is a completely synthetic, says Pharmion, This means the drug’s developers have been able to minimise its cardiotoxicity, whilst still retaining its effectiveness against tumours. In fact, clinical trials suggest amrubicin is more potent than other anthracyclines in lung cancer.

Pharmion said it will start a registration study of amrubicin in small cell lung cancer during the second half of 2007.

In Phase II studies conducted in Japan, amrubicin showed clinical efficacy both as a single agent and in combination with cisplatin. For example, in a study involving previously-untreated SCLC patients, the drug produced an overall response rate of 76% on its own, and 88% when given alongside cisplatin. Median survival with amrubicin as a single agent was 11.7 months and in combination with cisplatin, median survival was extended to 13.6 months.

In a Phase II study involving previously treated patients with SCLC, amrubicin as a single agent has shown overall response rates ranging from 46% to 53%, with median overall survival rates of 9.2 to 11.7 months, said Pharmion.