According to a recent study, led by Vivek Subbiah, MD, of The University of Texas MD Anderson Cancer Center, dabrafenib in combination with trametinib is an effective treatment option for patients with BRAFV600E -mutated biliary tract cancer (BTC). In an interview with i3 Health, Dr. Subbiah shares insights on the significance of these study results and unmet needs and future treatment in this patient population.
What are the most challenging aspects of treating patients with BRAFV600E -mutated BTC?
Vivek Subbiah, MD: Biliary tract cancer is an aggressive disease with poor clinical outcomes. Most patients with this malignant disease are diagnosed at an advanced stage, and 5-year survival is 18%.
Can you comment on the significance of your study's findings?
Dr. Subbiah: To our knowledge, we report the first prospective analysis of a cohort of patients with BRAFV600E-mutated BTC treated with a combination of a BRAF inhibitor (dabrafenib) and a MEK inhibitor (trametinib). The combination was active, and patients in this study did not have some of the secondary cutaneous malignant diseases that have been recorded previously with BRAF inhibitor monotherapy. Together, these observations support the combination of dabrafenib and trametinib as an option for patients with refractory BRAFV600E-mutated BTC, a treatment-resistant population for whom, to our knowledge, no effective treatment is currently available.
What are the unmet needs that still exist in this patient population?
Dr. Subbiah: The standard of care for patients with BTC includes resection (for patients with resectable disease) and chemotherapy with gemcitabine and cisplatin. In advanced disease, the standard chemotherapy regimen is associated with a median progression-free survival of 8 months and median overall survival of 12 months. So, we really need effective therapies in this cancer.
How do you see the treatment landscape evolving in the coming years?
Dr. Subbiah: Interestingly, BTC has become the poster child for rare disease precision oncology. Multiple actionable alterations have been identified in BTC including FGFR2 fusions, IDH1, HER2, NTRK fusions, RET fusions and in this study, BRAF mutations. Regarding magnitude of benefit, BRAF compares favorably well. Hence, genomically-targeted therapies and agents that arm the immune system should be tailored as treatment options for specific subsets of patients who may potentially benefit.
Do you have any advice for community oncologists who treat this patient population?
Dr. Subbiah: Routine testing for BRAFV600E mutations in addition to other alterations like FGFR2 fusions should be considered in all patients with biliary tract cancer.
About Dr. Subbiah
Vivek Subbiah, MD, is an Associate Professor in the Investigational Cancer Therapeutics department at The University of Texas MD Anderson Cancer Center. Dr. Subbiah is also the Center Clinical Medical Director of the Clinical Center for Targeted Therapy, Cancer Medicine division at The University of Texas MD Anderson Cancer Center.
Subbiah V, Lassen U, Elez E, et al (2020). Dabrafenib plus trametinib in patients with BRAFV600E – mutated biliary tract cancer (ROAR): a phase 2, open-label, single-arm, multicenter basket trial. Lancet Oncol. [Epub ahead of print] DOI:10.1016/S1470-2045(20)30321-1
Transcript edited for clarity. Any views expressed above are the speaker's own and do not necessarily reflect those of i3 Health.