Both Herceptin (chemical name: trastuzumab) and Tykerb (chemical name: lapatinib) are targeted therapy medicines that are approved to treat certain HER2-positive breast cancers. Herceptin is approved to be used after surgery (adjuvant treatment) to lower recurrence (the cancer coming back) risk of early-stage, HER2-positive breast cancers with a high risk of recurence. Tykerb isn't approved to be used that way.
The ALTTO (Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization) study is looking for the best ways to use Tykerb and Herceptin, either alone or in sequence. In one arm of the study, women diagnosed with early-stage, HER2-positive breast cancer were randomly assigned to receive either Tykerb or Herceptin after breast cancer surgery. This arm of the ALLTO study was designed to see how Tykerb compared to Herceptin to treat early-stage, HER2-positive breast cancer.
On Sept. 9, 2011, GlaxoSmithKline, the company that makes Tykerb, announced that this arm of the ALTTO study was going to end since an early analysis of the results so far showed that Tykerb wasn't working as well as Herceptin to lower the risk of recurrence. Other arms of the ALLTO study will continue. These arms are studying using Tykerb and Herceptin:
- one after another (in sequence)
- in combination
after surgery to reduce the risk of early-stage, HER2-positive breast cancer coming back.
HER2-positive breast cancers have too many copies of the HER2/neu gene, which make too much of the HER2 protein. HER2-positive breast cancers tend to be aggressive, so doctors may recommend adjuvant treatment for them. Herceptin and Tykerb work against HER2-positive breast cancers by blocking the cancer cells' ability to receive growth signals. Herceptin is given intravenously. Tykerb is a pill taken by mouth.
In addition for use to lower the risk of recurrence of early-stage, HER2-positive breast cancer with a high risk of recurrence, Herceptin also is approved to treat advanced-stage, HER2-positive breast cancer.
Tykerb is approved to be used in combination with the chemotherapy Xeloda (chemical name: capecitabine) to treat HER2-positive, metastatic breast cancers that have stopped responding to certain chemotherapy medicines and Herceptin. Tykerb also is approved to be used in combination with the hormonal therapy Femara (chemical name: letrozole) to treat postmenopausal women diagnosed with hormone-receptor-positive, HER2-positive, advanced-stage breast cancer.
It's important to know that the ALTTO study results haven't caused any concern about Tykerb's benefits for its approved uses.
If you're in the ALTTO trial, talk to your doctor about one study arm ending and whether it affects your treatment plan in any way.
To learn more about Herceptin and Tykerb, visit the Breastcancer.org Targeted Therapies pages.