Expert Perspectives of a 67-Year-Old Man with Metastatic HER2+ Gastric Cancer - Episode 6

Recent Advances and Future Directions in the Management of HER2+ Gastric Cancer

John Marshall, MD

An expert in gastric cancers provides insight on the recent advances and future directions for the management of locally advanced and metastatic gastric cancers.

John Marshall, MD: This is a big positive event for us with HER2-positive gastric and gastroesophageal [GE] junction cancers. It's not as if we haven't been trying. There have been a bunch of clinical trials in lines of therapy in HER2-positive metastatic disease, GE junction, and gastric cancer. They have been basically suggestive, but not positive. This trastuzumab deruxtecan therapy is a breakthrough for us as it maintains a response rate. It maintains the benefit through lines of therapy, and again in patients, 70% of which didn't have repeat testing. However, there are still many questions to be asked about this. What will be the role of this therapy in earlier lines of therapy? Can we combine it with other treatments? Can we combine it with immunotherapy for example? There are some fascinating studies being done in that space.

I sense that this will be a medicine that's here to stay and will be incorporated in other settings. HER2 treatment in the adjuvant world and in the neoadjuvant world has yet to be firmly established, so still is a clinical trial question and is again being studied to try and demonstrate if we could add HER2 targeting to neoadjuvant approaches, or in the postoperative adjuvant setting to improve outcomes as we see in some other cancers. Overall, that is still a research question, but we all hope that we will get data that supports doing that and improve our overall outcomes. Let's face it, this is still a very difficult disease where we are failing to the level that we need to do. The biggest point about this new evidence is that we must be doing molecular testing. We want to do that at first-line. You want to incorporate HER2 targeting in first line, but you now have HER2 targeting into second- and subsequent lines of therapy to add to the several other recently approved therapies in this space.

You are getting an increased therapeutic portfolio. It is dictated by molecular testing, so molecular testing must be done and must be documented. If you're using trastuzumab deruxtecan in second or third line, watch out for the interstitial lung disease. Know that you've got a new medicine in hand that can deliver significant response rates and improvements in outcome for our patients with HER2-positive gastroesophageal and GE junction cancers. Thanks a lot.

This transcript has been edited for clarity.