By Lauretta Ihonor, medwireNews Reporter
Phase I trial results show that the chemotherapy drug crizotinib may be fast-acting and produce long-lasting treatment responses in patients with anaplastic lymphoma receptor tyrosine kinase (ALK)-positive non-small-cell lung cancer (NSCLC).
In addition, more than 60% of patients in the trial exhibited an objective response to the drug and had a median progression-free survival of almost 10 months, explain Ross Camidge (University of Colorado, Aurora, USA) and team.
Writing in The Lancet Oncology, the authors add that crizotinib may also boost 1-year survival from the current rate of 50% (or lower) to 75% among these patients.
Oral crizotinib 250 mg administered twice daily and in 28-day cycles, achieved total remission in 2.0% and partial remission in 58.7% of the 143 ALK-positive NSCLC patients (median age 52 years) enrolled in the study.
Participants were followed up for a median period of 16.3 months. During this time, drug safety and efficacy were assessed at intervals of 2-4 weeks. Tumor response was assessed 8-weekly using Response Evaluation Criteria in Solid Tumors (RECIST) guidelines.
A median period of 7.9 weeks was observed between initiation of drug-use and first objective disease response to treatment. This response persisted for a median period of 49.1 weeks.
This, say Camidge et al, demonstrates that crizotinib offers "rapid and durable" responses in ALK-positive NSCLC patients.
Furthermore, treatment response appeared to be independent of patient age, gender, performance status, and line of therapy.
For example, similar response rates of 60.2% and 65.0% were observed among patients aged under 65 years and 65 years or older, respectively.
The study, which commenced in August 2008, is not yet complete; therefore, overall survival data is not yet available. However, estimates based on current data indicate a 1-year survival rate of 74·8% in the study group.
Common side effects seen in the group were predominantly gastrointestinal, but these became less prominent when the drug was taken with food.
Of note, 6.2% of patients experienced neutropenia and 4.2% had lymphopenia.
Camidge et al conclude: "In conjunction with a high proportion of patients having an objective response, these data support the potential of crizotinib to have a major effect on the lives of patients with ALK-positive NSCLC."
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