T-DMI (trastuzumab plus DMI)
 

Roche Presents Several Abstracts for New Targeted Cancer Drugs at ASCO

June 03, 2009
T-DMI

Roche presented final efficacy results from a Phase II study of a new antibody-drug conjugate, T-DMI (trastuzumab plus DMI), that has shown treatment benefit in metastatic breast cancer patients whose cancer had progressed despite treatment with two or more HER2-targeted therapies.
In the study, by Krop et al., researchers looked at the correlation between patient response to T-DMI and HER2 status in 112 metastatic breast cancer patients. HER2 status was established in patients by fluorescent in situ hybridization, immunohistochemistry, mRNA quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay.
In the trial, 107 patients were evaluable for efficacy at median 4.4 months follow-up. Of these patients 42 or 39 percent had partial responses on T-DM1. Out of 86 patients centrally tested, 64 were HER2 positive and 15 were HER2 negative, as confirmed by FISH and/or IHC. Half of 64 HER2-positive and 13 percent of 15 HER2-negative patients had partial responses.
Among 39 HER2-positive patients who were efficacy-evaluable with qRT-PCR data, 68 percent had partial responses above median levels while 35 percent had partial responses below median levels.
"HER2-positive patients had better responses to T-DM1 than HER2-negative patients, although a small number of partial responses were observed in HER2-negative patients," the study authors reported. "Assessment of HER2 expression by qRT-PCR may identify patients more likely to respond to T-DM1 therapy."
DM1 is developed by ImmunoGen. Genentech and Roche are conducting a broad clinical program with T-DM1 in HER2-positive breast cancer.
According to Roche, a Phase III study evaluating T-DM1 for second-line advanced HER2-positive breast cancer was initiated this year.