Doctors and investors at a cancer conference starting on Friday will be keen to find out more on the effectiveness of two promising new breast cancer drugs from Swiss drugmakers Roche and Novartis.

Roche's T-DM1 and Novartis's Afinitor have been designed to treat two specific types of breast cancer and are among the latest examples of the tailored therapies increasingly being used in oncology.

A mid-stage trial has already shown recently that T-DM1, which combines Roche's Herceptin with a potent cell-killing payload delivered directly to cancer cells, helped patients live longer without their disease getting worse compared with those taking Herceptin and conventional chemotherapy.

It also showed that T-DM1 had fewer side effects. Investors will eye the more detailed data sets to see the size of the benefit and whether the reduced side effects increased patients' likelihood of sticking with the treatment.

Roche and Novartis, the top two global players in oncology, are due to present more detailed data on their drugs at the EMCC European cancer congress, which runs from September 23-27 in Stockholm.

"We have further data at the next cancer conference, and we believe they are quite astounding," Stefan Frings, Global Head of Medical Affairs Oncology at Roche, told Reuters at the group's headquarters in Basel.

Roche hopes the T-DM1 results will help it protect its multibillion-dollar Herceptin franchise even as Herceptin loses exclusivity in the coming years.

T-DM1, which Roche is developing with Immunogen, is a new kind of "armed antibody."
The fact that the drug delivers its toxic payload directly into cells is thought to be key to why it causes fewer cases of common chemotherapy side effects such as hair loss and low white blood cell counts.

"For T-DM1 we want to know more about the extent of those benefits as that ultimately has an impact on the pricing issue, which is important for Roche as they seek to combine more products to treat breast cancer," Helvea analyst Karl-Heinz Koch said.

Novartis has also sounded an upbeat note about the prospects for Afinitor, also known as everolimus, which is already approved for other types of cancer, such as kidney and a rare type of pancreatic cancer.

CEO Joe Jimenez told Reuters in a recent interview it could generate sales of at least $1 billion if it makes it to the market for patients with hormone-sensitive breast cancer. It is planning to file for regulatory approval by the end of 2012.

The interim analysis of a late-stage trial showed Afinitor taken with Pfizer's oestrogen-blocker Aromasin, also known as exemestane, extended the time patients lived without their tumor growing.

More details from the BOLERO-2 study will be presented in Stockholm.

Novartis is seeking to use Afinitor, which works by targeting the protein mTOR in cancer cells, to treat women with hormonal receptor-positive breast cancer who have not responded to initial hormonal therapy.

"After around 25 years of hormonal therapy for this type of patient population, this study represents a really innovative therapy that is a step forward for this group of patients with breast cancer," Alessandro Riva, Global Head of Oncology Development and Medical Affairs at Novartis, told Reuters.

Worldwide, there are approximately 220,000 newly diagnosed cases of ER+HER2- advanced breast cancer each year that could benefit from Afinitor, Riva said, adding the drug was well tolerated and can be taken over a prolonged period.

"The breast cancer story is a very nice journey for everolimus," Riva said. "The journey is not finished because we have a large program now ongoing in the HER2-positive metastatic breast cancer patients."


Targeted therapies are treatments that use drugs to identify and attack specific cancer cells without harming normal cells. Monoclonal antibodies, such as Herceptin, and tyrosine kinase inhibitors, such as GlaxoSmithKline's Tykerb, are two types of targeted therapies used in breast cancer.

Roche first broke ground in this field just over a decade ago with Herceptin, which was designed to treat women with breast cancer who make too much of the HER2 protein. About 20 percent of breast cancer patients have these particularly aggressive types of tumors.

It is now also developing pertuzumab, another medication for women with HER2-positive metastatic breast cancer, which it is ultimately hoping to use with T-DM1 to attack the cancer on several different fronts.

Roche is planning to file for approval of pertuzumab this year after positive results from a late-stage trial.

Roche's and Novartis's bid to combine treatments comes as scientists increasingly understand that cancer cells are able to keep growing by finding ways to outmaneuver treatments, so using a cocktail of drugs could be key to the fight.


Afinitor may also be able to capitalize on the recent woes of another of Roche's cancer drugs, Avastin, which was once tipped to become the world's best-selling drug.

U.S. authorities proposed revoking its approval in advanced breast cancer at the end of last year, a decision that dented sales of Avastin in breast cancer on both sides of the Atlantic.

A few months later, advisers to the Food and Drug Administration agreed that the drug was not safe or clinically beneficial, dealing a blow to Roche and also to those patients who had insisted it had saved their lives.

"Afinitor could bring in at least $1.5 billion in sales in the second line HER2-advanced breast cancer setting, and if Novartis could extend use to the first line as well, sales could increase to around $4 or $5 billion," Helvea's Koch said.

"The only competition out there at the moment is Avastin, but it has been knocked off its throne in the United States and also to a large extent in Europe," Koch said.