Giving a HER2-targeting drug before surgery in women with early-stage HER2-positive breast cancer has become routine, but doesn’t always clear away all tumour tissue. Now, Roche has clinical data showing its antibody-drug conjugate Kadcyla offers a second-line of treatment for these patients.
In the KATHERINE study, giving Kadcyla (ado-trastuzumab emtansine) to women with residual disease despite pre-surgery (neoadjuvant) therapy significantly reduced invasive disease-free survival or IDFS compared to Herceptin (trastuzumab), Roche’s older HER2 inhibitor.
Roche isn’t revealing the data from the study just yet, saying it will do so at the San Antonio Breast Cancer (SABC) conference in December, but is now preparing to file for approval of the ADC in this new indication “to health authorities around the world”.
Neoadjuvant therapy is given with the intention of achieving a cure for patients with early-stage cancer, and Herceptin and follow-up HER2 drug Perjeta (pertuzumab) have been approved for this use for several years. When patients still have some cancer remaining despite this treatment, they are at dramatically increased risk of the cancer coming back, so they often continue with HER2 therapy to try to prevent that happening.
Kadcyla combines the active ingredient in Herceptin with a chemotherapy drug (TDM1) designed to improve its efficacy at killing cancer cells, but until the KATHERINE data were available there was no evidence that giving it in place of Herceptin would actually make patients less likely to relapse.
With Herceptin and follow-up Perjeta (pertuzumab) already approved for neoadjuvant use and Kadcyla on course for an indication in post-neoadjuvant residual disease, Roche is increasingly dominant in early-stage HER2-positive breast cancer, which accounts for around 20% of all breast tumours. That will help support the $10bn-plus franchise as Herceptin faces the threat of biosimilar competition in some European markets, including the UK.
Meanwhile, moving Kadcyla up the treatment pathway should help keep the ADC – currently the smallest product of the three – ahead of emerging rivals, such as Daiichi-Sankyo’s ADC trastuzumab deruxtecan (DS-8201) which is moving into a phase 3 programme.
“We are highly encouraged by these positive results with adjuvant Kadcyla treatment in people with HER2-positive early breast cancer who have residual disease after neoadjuvant therapy,” said Sandra Horning, Roche’s chief medical officer.
“We look forward to discussions with regulatory authorities with the goal of bringing this new treatment option to patients as soon as possible.”