Precision Medicine Wrap-up: Using Biomarkers to Guide Therapy in Various Cancers

As cancer therapies become more targeted, biomarkers are an increasingly important tool to help understand a patient’s individual cancer and identify the treatments that will work best.

For instance, in colorectal cancer, approximately 40% of patients have KRAS wild-type disease, and established therapies such as cetuximab and panitumumab are effective, Atrayee Basu-Mallick, MD, a medical oncologist at Sidney Kimmel Cancer Center, and clinical assistant professor at the Thomas Jefferson University, recently told OncLive^®.

On the other hand, approximately 8% of patients with colorectal cancer have a BRAF mutation, and the median survival for patients with BRAF wild-type disease is only about 13 months. Chemotherapy is not very effective for most of these patients, but they may be able to receive a combination therapy of encorafenib plus cetuximab or encorafenib, cetuximab, and binimetinib.

These combination therapies would not be ideal for patients with HER2-positive disease, though, Basu-Mallick explained. For those patients, trastuzumab plus pertuzumab or trastuzumab plus lapatinib have resulted in more favorable overall response rates.

Watch the interview with Basu-Mallick on OncLive^®.

In a separate interview with OncLive^®, Michael Devitt, MD, explained how biomarker-guided therapies are being used in patients with bladder cancer. According to Devitt, hematologist and oncologist and assistant professor at the University of Virginia Medical Center, noted that PD-L1 and FGFR are the 2 biomarkers frequently used in bladder cancer.

PD-L1 may identify patients who were ineligible for cisplatin in the frontline setting but may benefit from treatment with carboplatin-based chemotherapy or immunotherapy. Patients with low or no expression of PD-L1 would not benefit from frontline immunotherapy because their response rates to PD-1 inhibitors are low, he explained.

Watch the interview with Devitt.

Lastly, new research has identified patients with recurrent ovarian cancer who are more likely to respond to rucaparib. The phase 2 ARIEL2 trial found that RAD51C and RAD51D mutations and high-level BRCA1 promotor methylation are predictive of response to rucaparib. Meanwhile, among patients who were naïve to poly (ADP-ribose) polymerase inhibitors, platinum sensitivity was a strong predictor of response to rucaparib.

In homologous recombination deficiency–associated high-grade ovarian cancer, patients with better outcomes on rucaparib had platinum-sensitive disease and had received fewer lines of prior platinum treatments (1 or 2 prior therapies vs 3 or 4 prior therapies).

Read more about the study on OncLive^®.