Use of the epidermal growth-factor receptor inhibitor erlotinib led to about a 30% reduction in duodenal polyp burden after 6 months of once-weekly treatment for patients with familial adenomatous polyposis (FAP) in a phase 2 clinical trial.
“If existing data are confirmed and extended through future research, this strategy has the potential for substantial impact on clinical practice by decreasing, delaying, or augmenting endoscopic and surgical interventions as the mainstay for duodenal cancer prevention in this high-risk patient population,” the study team says.
FAP is a rare genetic condition that markedly raises the risk for colorectal polyps and cancer.
“The biological pathway that leads to the development of polyps and colon cancer in patients with FAP is the same biological pathway as patients in the general population,” study investigator Niloy Jewel Samadder, MD, with the Mayo Clinic, Rochester, Minnesota, says in a news release.
“Our trial looked at opportunities to use chemoprevention agents in patients with FAP to inhibit the development of precancerous polyps in the small bowel and colorectum,” Samadder explains.
In an earlier study, the researchers found that the combination of the COX-2 inhibitor sulindac (150 mg twice daily) and erlotinib (75 mg daily) reduced duodenal polyp burden.
However, the dual-drug strategy was associated with a relatively high adverse event (AE) rate, which may limit use of the combination for chemoprevention, as reported by Medscape Medical News.
This phase 2 study tested whether erlotinib’s AE profile would be improved with a once-weekly dosing schedule while still reducing polyp burden.
The study was first published online in the journal Gut.
In the single-arm, multicenter study, 46 adults with FAP (mean age, 44 years; 48% women) self-administered 350 mg of erlotinib by mouth one time per week for 6 months. All but four participants completed the 6-month study.
After 6 months of weekly erlotinib, duodenal polyp burden was significantly reduced, with a mean percent reduction of 29.6% (95% CI: -39.6% to -19.7%; P < .0001).
The benefit was observed in patients with either Spigelman 2 or Spigelman 3 duodenal polyp burden.
“Though only 12% of patients noted a decrease in Spigelman stage from 3 to 2 associated with therapy, the majority of patients (86%) had stable disease while on treatment,” the study team reports.
GI polyp number (a secondary outcome) was also decreased after 6 months of treatment with erlotinib (median decrease of 30.8%; P = .0256).
While once-weekly erlotinib was “generally” well tolerated, grade 2 or 3 AEs were reported in 72% of patients; two suffered grade 3 toxicity. Nonetheless, the AE rate was significantly more than the expected null hypothesis rate of 50%, the study team states.
Four patients withdrew from the study because of drug-induced AEs, which included grade 3 rash acneiform, grade 2 infections (hand, foot, and mouth disease), grade 1 fatigue, and grade 1 rash acneiform. No grade 4 AEs were reported.
The most common AE was an erlotinib-induced acneiform-like rash, which occurred in 56.5% of study patients. The rash was managed with topical cortisone and/or clindamycin. Additional erlotinib-induced AEs included oral mucositis (6.5%), diarrhea (50%), and nausea (26.1%).
Summing up, Samadder and colleagues note that FAP “portends a heritable, systemic predisposition to cancer and the ultimate goal of cancer preventive intervention is to interrupt the development of neoplasia, need for surgery, and ultimately death from cancer, with an acceptable AE profile.”
The findings from this phase 2 trial support further study of erlotinib as “an effective, acceptable cancer preventive agent for FAP-associated gastrointestinal polyposis,” they conclude.
The study was sponsored by the National Cancer Institute. Samadder is a consultant for Janssen Research and Development, Recursion Pharmaceuticals, and Cancer Prevention Pharmaceuticals.
Gut. Published online May 30, 2022. Full text
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