Phase II Trial of New Targeted Therapy Stopped Early
A phase II trial studying the effects of the medicine MM-302, when used with trastuzumab, on HER2-positive breast cancers has been stopped, according to a press release from Merrimack Pharmaceuticals, maker of MM-302. A safety board found the medicine did no better than other treatments available now.
Background and design
HER2-positive breast cancers grow in response to human epidermal growth factor receptor-2, a protein found naturally in your body. Doctors often recommend trastuzumab (Herceptin) or other medicines like pertuzumab (Perjeta) and T-DM1 (Kadcyla) to target cancer cells with HER2 receptors. But over time, the cancer may stop responding to these medicines.
Researchers are looking for ways to help treatments work longer. MM-302 is another medicine that targets cells with HER2 receptors. The phase II HERMIONE trial was designed to see if MM-302 could help make trastuzumab effective again for people whose cancer grew despite past treatment with trastuzumab and T-DM1.
People who participated were randomly assigned to one of two groups:
- The treatment group was given MM-302 and trastuzumab every 3 weeks by vein.
- The control group was given trastuzumab every 3 weeks by vein and chemotherapy recommended by their doctor.
HERMIONE was an open-label trial, meaning both the doctors and participants knew what treatment was being given.
Researchers planned to compare the length of time it took for the disease to grow or travel to other parts of the body in each group and also to compare the side effects in the treatment group and the control group.
Reason for Stopping Trial
In a statement released December 21, Merrimack Pharmaceuticals announced the HERMIONE trial was stopped on the recommendation of the Data and Safety Monitoring Board. A DSMB is a group of experts, independent from the people running the trial, that reviews data from a study to see whether participants are safe and the study is being done properly. It can recommend changing or stopping the trial based on the data.
The DSMB recommended stopping the trial after finding people in the MM-302 group did not seem to be doing better than they would on other treatments available. Though no new safety concerns were discovered, both the control group and the treatment group (taking MM-302) in the HERMIONE trial saw the breast cancer grow sooner than expected, on average.
People enrolled in the trial can choose to stay on their current treatment plan after talking to their doctor, or ask about choosing a different plan.
What this means for you
Stopping the HERMIONE trial means MM-302 will not be added to the options for people with HER2-positive breast cancer that has stopped responding to targeted therapies.
It can be frustrating to read or hear about promising new treatments that do not become available. But many treatments that have promising results in labs, or even in early clinical trials, do not help as much as expected or may cause serious side effects. Clinical trials allow researchers to measure the effects of new medicines and compare them with existing treatments, both for how well they work and what side effects they cause.
You may be able to get new treatments not available to the public by participating in a clinical trial like HERMIONE. This can be good if the medicine is found to be more effective. But if data show the new treatment does not have the expected results, researchers have controls like the DSMB to stop the trial, protect your health and allow you to change your treatment.
We will report more about the decision to stop the trial when Merrimack, the maker of MM-302, publishes its findings.
The medical content in this story was previously reviewed by Francisco J. Esteva, MD.