What’s New in Gastrointestinal Stromal Tumor Research?

Research on gastrointestinal stromal tumors (GISTs) is being done in many medical centers and other institutions around the world. Scientists are learning more about what causes these tumors and how best to treat them. There has been a great deal of progress in recent years, especially in treating GISTs. 

Targeted therapy drugs

As researchers have come to understand more about the genetic changes that cause these tumors, they’ve been able to use newer targeted treatments (sometimes called precision medicines) to attack cancer cells with these changes. For example, mutations in the KIT or PDGFRA genes are present in the cells of most GISTs.

Targeted therapy drugs like imatinib (Gleevec), sunitinib (Sutent), regorafenib (Stivarga), and ripretinib (Qinlock) can affect cells with these gene changes and are often helpful in treating GISTs, but they tend to stop working over time. Doctors still aren’t sure exactly how and when to give them to make them most effective. For example, should these types of drugs be given after surgery to all patients, even those with very small tumors? How long should drug treatment be continued? These and other questions are now being studied in clinical trials.

Other drugs that target the KIT or PDGFRA proteins are also being studied for use against GISTs. Some of these drugs have been shown to help some patients in early studies:

• Sorafenib (Nexavar)
• Nilotinib (Tasigna)
• Dasatinib (Sprycel)
• Pazopanib (Votrient)
• Ponatinib (Iclusig)

Other, newer drugs that target these proteins are also being studied, such as:

• Crenolanib
• Binimetinib (Mektovi)

Drugs that target different proteins involved in GIST cell growth are now being tested as well.

Immunotherapy

Immunotherapy is the use of medicines to boost the body’s own immune response to help fight the cancer.

Immune checkpoint inhibitors

Immune system cells normally have proteins that act as checkpoints to keep them from attacking other healthy cells in the body. Cancer cells sometimes take advantage of these checkpoints to avoid being attacked by the immune system.

Newer drugs called immune checkpoint inhibitors work by blocking these checkpoint proteins, which can boost the immune response against cancer cells in the body. These drugs have been shown to be helpful against many types of cancer in recent years. Some of these drugs, such as such as nivolumab (Opdivo) and ipilimumab (Yervoy), are now being studied for use against GISTs.

Monoclonal antibodies

Monoclonal antibodies are man-made versions of immune system proteins created to attack specific parts of cancer cells. An example now being studied for use against GISTs is XmAb18087. This antibody attaches to cells that have the somatostatin receptor 2 (SSTR2) protein, and brings them into contact with immune cells called T cells. The goal is to activate the person’s immune system to attack the cancer cells.

Other types of immunotherapy are now being explored as well.

People with GISTs that are no longer responding to standard treatments may want to ask their doctor about clinical trials studying these newer types of treatments.