A phase 2 study designed to compare varlitinib with placebo as first-line treatment for certain patients with gastric cancer failed to meet its primary endpoint of significant reduction in tumor size after 12 weeks of treatment.
Varlitinib (ASLAN001, ASLAN Pharmaceuticals) is an oral, reversible, small molecule pan-HER inhibitor that targets HER1, HER2 and HER4. The agent is under investigation as treatment for gastric, biliary tract, breast and colorectal cancers.
ASLAN conducted a placebo-controlled, double-blind study to compare modified FOLFOX6 chemotherapy — which consists of leucovorin, calcium, fluorouracil and oxaliplatin — plus either varlitinib or placebo as first-line therapy for patients with HER1/HER2 co-expressing advanced or metastatic gastric cancer.
The percentage of patients with baseline ECOG status of 0 was higher in the control group (46.2% vs. 19.2%). Otherwise, patient characteristics were balanced between groups.
Results by independent central review showed varlitinib-treated patients achieved greater average tumor shrinkage after 12 weeks (22% vs. 12.5%) but the difference did not reach statistical significance.
Results also showed a trend toward improved PFS in the varlitinib group.
A higher percentage of patients assigned modified FOLFOX6 plus placebo experienced grade 3 or worse adverse events (88.5% vs. 73.1%).
The FDA has granted orphan drug designation to varlitinib for gastric cancer and cholangiocarcinoma, a type of biliary tract cancer.
“First-line gastric cancer is a very challenging indication to treat and the majority of patients present with advanced disease at initial diagnosis. To date, no targeted therapies have been approved to treat gastric cancer with low HER-family expression,” Mark McHale, BS, PhD, chief operating officer for ASLAN Pharmaceuticals, said in a company-issued press release. “[Although] we are disappointed by the study findings, we are encouraged by the positive safety data and remain confident that varlitinib’s potent pan-HER inhibition has the potential to yield benefits in biliary tract cancer where HER family expression is known to be high.”