IMPRESS Study Results also Presented at the ESMO 2014 Congress Provide Increased Understanding of Treatment Options for Patients with EGFR Mutation Positive Advanced Non-Small Cell Lung Cancer who have Developed Acquired Resistance to First Line IRESSA
Updated data from the ongoing AURA study of AZD9291 shows encouraging, although still immature, median progression free survival of 9.6 months (95% CI 8.3 to NC) in patients with epidermal growth factor receptor mutation positive (EGFRm) T790M+ advanced non-small cell lung cancer (NSCLC) who had disease progression following treatment with an EGFR tyrosine kinase inhibitor (EGFR TKI). The progression free survival (PFS) results are based on a 30% data maturity from 138 patients.
Data presented at the European Society for Medical Oncology (ESMO) 2014 Congress support and strengthen the results highlighted earlier this year at the American Society for Clinical Oncology (ASCO) Congress.
The ongoing AURA Phase I/II study is investigating AZD9291 in patients with advanced NSCLC. As of 1 August, 253 pre-treated patients have been dosed on this study and the 80 mg once daily dose has been selected for late stage development. The PFS results were coupled with a prolonged duration of response. In patients with EGFRm T790M+ advanced NSCLC treated at the 80 mg dose, the preliminary median duration of response was 8.2 months.
James Chih-Hsin Yang, MD, PhD, professor of Graduate Institute of Oncology and Director of Cancer Research Center at National Taiwan University College of Medicine, said:
We are optimistic and encouraged by the rates of progression free survival and duration of response results in patients treated with AZD9291. While the data are still immature, they are based on robust patient numbers and this give us confidence that this is a trend that will continue. To date, the longest duration of response is still ongoing at more than 11 months.
The confirmed overall response (ORR) rate for patients with EGFRm T790M+ advanced NSCLC treated at the 80 mg dose was 70 percent. For the 127 evaluable patients with EGFRm T790M+ advanced NSCLC treated at all doses, the confirmed ORR was 61 percent (78/127). As expected, patients with EGFRm T790M- advanced NSCLC had a lower confirmed ORR (21 percent; 13/61) and a shorter median PFS (2.8 months).
The most common adverse events (AEs) in the AURA study at the 80 mg dose (N=90) were diarrhoea and rash, which were mostly mild (Grade 3 diarrhoea 1%; Grade 3 rash: 0%).1 Drug-related Grade 3 or greater AEs occurred in 10 patients (11%) treated at this dose, with no patients requiring dose reductions and one patient discontinuing medication due to a drug-related AE.
The most common AEs at all doses (N=253) were diarrhoea and rash, which were mostly mild. Drug-related Grade 3 or greater AEs occurred in 33 patients (13%), with 17 patients requiring dose reductions (7%) and 7 patients (3%) discontinuing medication due to a drug-related AE.
As of 12 September, more than 620 patients have been dosed with AZD9291 within the full clinical trial programme; pneumonitis-like events have been reported in approximately two percent of patients (13 events). Of these events, seven were Grade 1 or 2; three were Grade 3 and one Grade 5. Pneumonitis has been associated with both lung cancer itself, as well as available treatments for this disease.
Results were also presented at the ESMO 2014 Congress on preliminary evidence of activity in NSCLC brain metastases and in first line patients with EGFRm NSCLC, supporting further investigation of AZD9291 in both of these settings.
In addition, data on the use of circulating tumour DNA (ctDNA), present in the plasma of NSCLC patients, as a predictive biomarker for response to AZD9291 were presented. There was a 65 percent response rate to treatment with AZD9291 at all dose levels in patients with T790M mutation detected using ctDNA in the AURA trial. ctDNA may offer an attractive alternative for a non-invasive test to provide tumour genotyping in patients unable to supply evaluable tumour samples at biopsy or rebiopsy following first line EGFR-TKI failure. IRESSA® (gefitinib) recently became the first EGFR-TKI in Europe to have a label allowing the use of ctDNA for the assessment of EGFRm status in those patients where a tumour sample is not evaluable.
AstraZeneca has initiated both Phase II and Phase III studies in patients with EGFRm T790M+ advanced NSCLC who had disease progression following treatment with an EGFR TKI (AURA 2 and AURA 3 respectively). In addition, a Phase III study evaluating AZD9291 in first line EGFRm advanced NSCLC is scheduled to start later this year. AstraZeneca is also currently investigating the combination of AZD9291 with MEDI4736 (PDL-1 immunotherapy), selumetinib (small molecule MEK inhibitor) and AZD6094 (small molecule MET inhibitor) in NSCLC.
Antoine Yver, Head of Oncology, Global Medicines Development, AstraZeneca, said:
The AZD9291 data at the ESMO 2014 Congress reinforce the clinical activity results presented at ASCO for this investigative therapy and continue to demonstrate how diagnostic-led treatments could improve patient care. AstraZeneca is focused on developing novel treatments that address the genetic drivers underlying lung cancer as well as overcoming its resistance mechanisms. For over 40 years AstraZeneca has delivered innovative drugs to improve the available options for cancer patients, including IRESSA, the first targeted therapy for patients with EGFRm advanced NSCLC.
AstraZeneca also presented data from the investigational Phase III IMPRESS study at the ESMO 2014 Congress. The study was a second line, combination study in patients with EGFRm advanced NSCLC who have acquired resistance to first line IRESSA.
The IMPRESS study was designed to compare the efficacy and safety of continuing IRESSA, combined with cisplatin and pemetrexed up to six cycles (no pemetrexed maintenance), versus comparator placebo, combined with cisplatin and pemetrexed up to six cycles (no pemetrexed maintenance) following the development of resistance to first line treatment gefitinib.
The study did not meet its primary endpoint of a statistically significant improvement in PFS. The secondary endpoint of overall survival (OS) is still ongoing. At the primary endpoint of PFS analysis, the OS was immature (33% of events) and was not conclusive. Longer OS was suggested for the placebo plus cisplatin and pemetrexed arm, versus the IRESSA plus cisplatin and pemetrexed arm. Overall, IRESSA combined with cisplatin plus pemetrexed chemotherapy was well tolerated and in line with known safety profiles.
The IMPRESS results answer an important scientific question regarding the effectiveness of a treatment strategy that includes IRESSA in second line, in combination with cisplatin and pemetrexed in patients who have acquired resistance to IRESSA.
AstraZeneca is continuing to explore several treatment strategies with IRESSA, including the recent initiation of Phase I trials exploring the combination of IRESSA with MEDI4736 (PDL-1 immunotherapy), tremelimumab (CTLA-4 immunotherapy) and selumetinib (small molecule MEK inhibitor).