FROM THE 2017 ASCO ANNUAL MEETING
The targeted agent gefitinib is superior to the standard of care chemotherapy for treating resected early non–small cell lung cancer (NSCLC) harboring an epidermal growth factor receptor (EGFR) activating mutation, finds the phase III randomized Chinese ADJUVANT trial.
Gefitinib, an oral tyrosine kinase inhibitor that targets the EGFR kinase among others, is already approved by the Food and Drug Administration for treatment of locally advanced or metastatic disease having mutations in the gene for this receptor.
Trial results reported in a presscast leading up to the annual meeting of the American Society of Clinical Oncology showed that compared with vinorelbine and cisplatin combination chemotherapy, 2 years of gefitinib prolonged the time to recurrence or death by more than 10 months, reducing risk of these events by a significant 40%. Gefitinib also was better tolerated: The rate of grade 3 or worse adverse events with the targeted agent was one-fourth that seen with the chemotherapy.
“Targeted therapy can delay recurrence of intermediate-stage lung cancer after surgery. Two-year treatment duration of gefitinib is efficacious and tolerated well,” said lead study author Yi-Long Wu, MD , director of the Guangdong Lung Cancer Institute, Guangdong General Hospital, Guangzhou, China. “Adjuvant gefitinib should be considered as an important option for stage II to IIIA lung cancer patients with an activating EGFR mutation.”
The improved disease-free survival seen with gefitinib in ADJUVANT is “encouraging,” according to ASCO President-Elect Bruce E. Johnson, MD , chief clinical research officer and an Institute Physician at the Dana-Farber Cancer Institute in Boston.
Longer follow-up will be needed to obtain a full picture as the horizon for events in the adjuvant setting is more on the order of years, and the disease-free survival curves began converging over time, he noted. “We will ultimately be interested in seeing whether this actually prolongs survival in a longer follow-up study, which Dr. Wu’s group is planning to do.
“I haven’t changed my approach yet for the patients with EGFR-mutant lung cancer,” Dr. Johnson concluded. “But I will be following this [trial] very closely to see what happens to the survival.”
The new data from ADJUVANT will likely have several effects on the clinical management of NSCLC, according to presscast moderator and ASCO Chief Medical Officer Richard L. Schilsky, MD .
“I suspect that many doctors will begin testing these lung cancer tumors right after surgery, to see if they actually have an EGFR mutation. That is not currently standard of care in the U.S.; typically the testing doesn’t take place until the cancer recurs or becomes metastatic,” he said. “So that way, doctors and patients will know whether or not treatment with an EGFR inhibitor is even an option.
“If it is an option, then many factors will likely come into play, and most importantly we will be waiting for the survival data,” said Dr. Schilsky, professor emeritus at the University of Chicago. Another consideration is that the trial compared 12 weeks of chemotherapy with 2 years of continuous gefitinib therapy, the latter of which requires a long-term commitment to adherence by patients and carries much greater cost.
“At the end of the day, I think that once the survival data is known in particular, doctors and patients are going to have to have very thoughtful discussions about what is the magnitude of the survival benefit; what is the burden on the patient to take either cytotoxic chemotherapy for 12 weeks or 2 years of an oral treatment, which, while it is less toxic, is not without toxicity; and what’s the financial burden of that treatment choice going to be for the patient,” he concluded.
Eligibility for the ADJUVANT trial required completely resected pathological stage II-IIIA (N1-N2) NSCLC with an EGFR-activating mutation. In all, 220 patients were randomized evenly to receive gefitinib (Iressa) once daily for 24 months or vinorelbine plus cisplatin every 3 weeks for 4 cycles.
Results showed that median disease-free survival – the trial’s primary endpoint—was 28.7 months with gefitinib compared with 18.0 months with chemotherapy (hazard ratio, 0.60; P = .005), Dr. Wu reported in the presscast. Corresponding 3-year disease-free survival rates were 34% and 27%.
The rate of grade 3 or worse adverse events was 12.3% in the gefitinib group, compared with 48.3% in the chemotherapy group. Most types of events were less common with the tyrosine kinase inhibitor, with the exception of rash, diarrhea, and elevation of liver enzymes.
Dr. Wu disclosed ties with AstraZeneca, Roche, Merck, Boehringer Ingelheim; Lilly, Pierre Fabre, Pfizer, and Sanofi. The Chinese Thoracic Oncology Group and AstraZeneca Chin funded the trial.