By Caroline Copley
ZURICH (Reuters) - Swiss drugmaker Roche hopes data published this week will show it has a viable follow-on product to help fend off cheaper competition for its best-selling cancer drug, which loses patent protection in Europe later this year.
Roche is set to present full results early on Thursday of a late-stage study for its GA101 drug in chronic lymphocytic leukaemia (CLL), ahead of the American Society of Clinical Oncology annual meeting in Chicago from May 31 to June 4.
Niko Andre, Roche's head of medical affairs for oncology, said the data would make clear GA101's true potential as a new treatment option in CLL. "The data will speak for themselves," he said.
Roche is the world's largest maker of cancer drugs and GA101 is a key test of its ability to defend its business against cheaper copies, known as "biosimilars" because they are not identical matches of branded medicines.
GA101 is a follow-on to Roche's top-seller MabThera, also known as Rituxan. The treatment for blood cancer and rheumatoid arthritis had sales of $7 billion in 2012, but goes off patent in Europe at the end of this year.
The new drug typifies Roche's strategy of protecting its existing sales once top sellers lose exclusivity by developing better versions of its original medicines.
Roche has already made a running start in protecting its breast cancer drug Herceptin - off patent next year - by winning approval for two new drugs against the disease, Perjeta and Kadcyla.
Although the GA101 data are just for CLL, which is a smaller treatment area than non-Hodgkin's Lymphoma (NHL) and accounts for roughly 15 to 20 percent of Rituxan sales, analyst Fabian Wenner at brokerage Kepler Chevreux thinks the data will provide a good indication of its potential efficacy in NHL.
"NHL will be the real acid test. But the full data (in CLL) are the first kind of validation and that's important," Wenner said. "Headline data have shown a stronger efficacy and a longer endurance in the body, which bodes well for NHL."
Analysts and investors are also keen to see head-to-head data comparing GA101 with Rituxan, which will be presented at the American Society of Hematology meeting in December.
Roche said in January an analysis after the first stage of the comparative trial showed there is a possibility that GA101 will be better than Rituxan.
"The market was once worried about biosimilars eroding two of Roche's largest products from 2014 onwards," Deutsche bank analysts wrote in a note.
"Although Roche cannot fully protect them, Perjeta and Kadcyla in breast cancer and now GA101 give confidence of a continued profit stream in both a branded and biosimilar environment."
(Editing by Ben Hirschler and David Holmes)