The FDA has approved a new genetics-based cancer treatment that could open the door for more targeted mesothelioma therapy.
The drug is called larotrectinib. The drug company Bayer sells it under the brand name Vitrakvi.
Larotrectinib is unique because it is not specific to any one type of cancer. Instead, larotrectinib is based on a patient’s genetic biomarkers. It is the first drug of its kind to gain approval by the FDA.
What is a Genetics-Based Cancer Treatment?
A genetics-based cancer treatment is a drug that targets certain genetic mutations. Doctors find these mutations by testing for biomarkers. One mutation could cause breast cancer, colon cancer, or even pleural mesothelioma.
Some kinds of mutations are connected to only one type of cancer. Other mutations cause a range of different types of cancer.
Larotrectinib is based on a genetic mutation called TRK gene fusion. TRK fusion can be the reason for several different cancers, including mesothelioma.
The new genetics-based cancer treatment blocks three kinds of TRK. No matter where the cancer occurs in the body, if TRK fusion is the cause, larotrectinib may help.
Vitrakvi for TRK Fusion Cancers
In clinical trials, 75 percent of patients with TRK fusion cancers responded to the treatment. Seventy-three percent of responses lasted for at least six months. The authors of the new report call this response rate “remarkable”.
Twenty-two percent of patients with TRK fusion cancers had a complete response. This means that the targeted mesothelioma therapy stopped their cancer in its tracks.
“We now have the first therapy approved for this genomic alteration, regardless of cancer type” says David Hyman, MD, chief of the Early Drug Development Service at Memorial Sloan Kettering Cancer Center. Dr. Hyman was a principal investigator on the larotrectinib clinical trial.
Genetics-Based Cancer Treatment for Mesothelioma
The news about Vitrakvi is exciting for malignant mesothelioma patients. Mesothelioma is an aggressive cancer for which there are few good treatments.
This summer, researchers in Australia discovered that a small number of mesothelioma cases may be caused by TRK fusion. It was the first study to show a relationship between mesothelioma and TRK fusion. The study appeared in The Journal of Clinical Oncology.
In the study, most of the patients with this genetic abnormality had the biphasic mesothelioma subtype. Most also reported exposure to asbestos. For these mesothelioma patients, larotrectinib may offer a new treatment option.
Larotrectinib is also important because it shows how genetics-based cancer treatment is growing. The drug’s approval could pave the way for other kinds of targeted mesothelioma therapy.
One drawback of larotrectinib is that a cancer patient must have expensive genetic testing to find out if it could work for them. Immunohistochemical testing (IHC) can cost thousands of dollars.
Before the FDA approved larotrectinib, it was granted Orphan Drug status. An orphan drug is a drug designed to treat people with very rare cancers like mesothelioma.
About 2,500 American receive a mesothelioma diagnosis every year.
Laetsch, TW, and Hawkins, DS, “Larotrectinib for the treatment of TRK fusion solid tumors”, October 24, 2018, Expert Review of Anticancer Therapy, https://www.tandfonline.com/doi/abs/10.1080/14737140.2019.1538796?journalCode=iery20
Peters, G, et al, “NTRK and ALK rearrangements in mesothelioma and lung carcinoid”, June 2018, Journal of Clinical Oncology, http://ascopubs.org/doi/abs/10.1200/JCO.2018.36.15_suppl.e20558
Drilon, A, et al, “Efficacy of Larotrectinib in TRK Fusion–Positive Cancers in Adults and Children”, August 22, 2018, New England Journal of Medicine, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5857389/