Proposed Herceptin 'Biosimilar' Works as Well as Original Medicine in First Results from Trial

The new medicine, developed to work just like trastuzumab, could eventually make treatment for HER2-positive breast cancer more affordable
Breast Cancer News
May 18, 2017
By: 
Eric Fitzsimmons, Copy Editor and Content Coordinator
Reviewed By: 
Douglas Yee, MD

Researchers have been developing a biosimilar of trastuzumabinfo-icon (Herceptininfo-icon), the most common treatment for HER2-positive breast cancer. Now, a study published in the Journal of the American Medical Association shows that the proposed biosimilar MYL-1401O was the same as trastuzumab (Herceptin) in treating HER2-positive metastaticinfo-icon breast cancer.

The success of the phase III Heritage Study could mean future FDAinfo-icon approval for the medicineinfo-icon in development. If approved, MYL-1401O could be offered as an alternative to trastuzumab and result in HER2 targeted therapyinfo-icon becoming less expensive.

Background

Trastuzumab is a targeted therapy that has been approved, in combination with chemotherapyinfo-icon, to treat HER2-positive breast cancer since the late 1990s. HER2-positive breast cancer has been found to be more aggressiveinfo-icon than other breast cancer types, and it does not respond as well to chemotherapy and other medicines. The development of trastuzumab resulted in significantly improved outcomes for people with this type of the disease when it became widely available. But trastuzumab is also very expensive.

Unlike many medicines, trastuzumab is not made by a chemical process. It is a biologically engineered proteininfo-icon called a monoclonal antibodyinfo-icon. These types of proteins are created to attack certain parts of tumors. Because trastuzumab is a biological medicine — not a chemical — other companies are not able to exactly copy it like they do chemical-based medicines. Instead, they have to design a very similar biological medicine that works the same way in the body, called a biosimilar. For FDA approval, biosimilars have to be safe and have the same effects on the disease as the original medicine.

Trastuzumab’s maker also has a patent, a license that allows them to be the only company that makes and sells the medicine for a set period of time. The patent on trastuzumab already expired in Europe, and in 2019 its patent in the United States will expire. After that, other companies will be able to make and sell competing biosimilar medicines. This should make the treatment more affordable as companies lower the price to get people to choose their medicine.

Design

The Heritage Study evaluated the trastuzumab biosimilar, MYL-1401O, as a first-line treatment for people with metastatic HER2-positive breast cancer. People were randomly assigned to receive either trastuzumab or the biosimilar in combination with taxaneinfo-icon-based chemotherapy for 24 weeks, after which participants continued on the targeted therapy alone until the cancer grew or spread, the side effects became too much, or until death from any cause.

A total of 458 people were included in the study and were randomly assigned to two groups for treatment:

  • 230 were given the biosimilar.
  • 228 were given trastuzumab.

This journal article presents part 1 of the trial, with data from the first 24 weeks after the participants were assigned to treatment. It also includes some information through the next 24 weeks, including tumorinfo-icon growth and if people died. Findings on long-term effects from part 2 will be presented in a later article.

The Heritage Study was double-blind, meaning neither the women nor their doctors knew which medicine was being used.

Results

The study found that the biosimilar had about the same success as trastuzumab at treating the cancer:

  • 69.6 percent of cancers responded to the biosimilar and chemotherapy.
  • 64 percent of cancers responded to trastuzumab and chemotherapy.

The rate of success may not be exactly the same in different studies, so the FDA sets a range to decide if two medicines are equal. The percent of cancers that responded to the biosimilar was in the same range as those responding to trastuzumab.

Researchers also reported how often the cancer progressed and found the difference was not statistically significantinfo-icon between treatment groups. There was also no statistically significant difference in overall survival during the study:

  • 205 people in the biosimilar group lived through the 48 weeks of study.
  • 194 people in the trastuzumab group lived through the 48 weeks of study.

The number of people with serious side effects was about the same for the two treatments. Seven people in each group stopped treatment because of a serious side effectinfo-icon. The rate of people who reported any serious side effect was

  • 38.1 percent in the biosimilar group
  • 36.2 percent in the trastuzumab group

What This Means for You

You are able to buy aspirin from many different companies and they all have the same chemical to give you pain relief. The Bayer Company first released aspirin with a patent in 1899, but since the patent expired other companies are allowed to make and sell pills with the same medicine. These copies are called genericinfo-icon medicines. Companies are not able to make exact copies of a biological compound like trastuzumab so biosimilars are not considered a generic medicine, but they could have the same effect.

If you’re taking trastuzumab or your doctor has suggested it, you may know that it is an expensive medicine. The high price for treatment has strained the finances of many people in the U.S. and prevented people in other parts of the world from being able to get it. It’s probably very exciting to know a new medicine could come to the market that works just as well and may be more affordable.

Roche/Genentech is the company that owns the patent on trastuzumab right now, so they are currently the only company allowed to make and sell it. Owning the patent also means Roche/Genentech sets the price of the medicine. But that patent expires in 2019 and at that time, the biosimilar could cause prices to go down as other companies try to convince people to use their medicine.

You may see lower prices for HER2 targeted therapy in the future. But in two editorials running alongside the study, experts expressed concern that the companies would not bring the price of targeted treatments down enough to change who can afford to get it. One said prices for biosimilars in Europe have caused prices on some medicines to go down 25 to 30 percent. But even that price reduction would not be enough to make targeted therapy more accessible for people in many countries around the world, some of which participated in this study.

 

Rugo, H; Barve, A; Waller, C.; et al. Effect of a Proposed Trastuzumab Biosimilar Compared With Trastuzumab on Overall Response Rate in Patients With ERBB2 (HER2)-Positive Metastatic Breast Cancer.  JAMA. January 3, 2017. doi:10.1001/jama.2016.18305

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