Matching Tumor Mutations to Treatment for Salivary Gland Cancer
Posted: Thursday, February 6, 2020
Chemotherapy-free regimens matched to specific molecular alterations in patients with advanced salivary gland cancer were shown to be efficacious and may lead to improvement in objective response rates. R. Kurzrock, MD, of UC San Diego, published the results of a subgroup analysis of the phase IIa MyPathway trial she conducted with colleagues in the Annals of Oncology.
The MyPathway trial is an open-label, nonrandomized study that enrolled patients with treatment-refractory advanced solid tumors. It aims to provide targeted therapies to patients based on tumor characteristics. This analysis focused on 19 patients with salivary gland cancers who were treated based on genetic alterations. They received pertuzumab plus trastuzumab if they had a HER2 alteration with or without amplification/overexpression (16 patients), vismodegib if they had a PTCH-1/SMO mutation (1 patient), vemurafenib for BRAF V600 mutations (1 patient), or atezolizumab for a high mutational tumor burden (1 patient).
Of the 15 patients with HER2 overexpression or amplification, 9 had an objective response. These responses consisted of one complete and eight partial, for a total overall response rate of 60%. The clinical benefit rate, defined as an objective response or stable disease for at least 4 months, was 67%. The median response duration was 9.2 months; the median progression-free survival was 8.6 months, and the median overall survival was 20.4 months in these patients.
The patient who had a HER2 mutation without overexpression had stable disease, with a progression-free survival of 11 months. In addition, patients with mutations in PTCH-1, BRAF, and a high tumor mutational burden had partial responses, with progression-free survival times of 14.3 months, 18.5 months, and 5.5 months, respectively. No unexpected toxicities were reported.
“Results from MyPathway provide proof of principle for matching patients to effective, chemotherapy-free treatment of tumors based on molecular characteristics rather than [the] site of origin,” the authors concluded.
Disclosure: For full author disclosures, visit annalsofoncology.org.