TORONTO – (LA-NSCLC) in the phase 2 DETERRED trial.
In part 1 of the single-institution study, 10 patients underwent chemoradiation therapy (CRT) with low-dose carboplatin/paclitaxel followed by high-dose consolidation chemotherapy plus atezolizumab and atezolizumab maintenance for 1 year. Six patients in this group (60%) experienced grade 3 or higher adverse events (AEs). In part 2 of the study, 30 patients received concurrent atezolizumab and CRT followed by the same consolidation and maintenance used in part 1, and 17 (57%) experienced grade 3 or higher AEs, Steven H. Lin, MD, reported at the World Conference on Lung Cancer.
Grade 3 or higher AEs were associated with atezolizumab in 30% and 23% of patients in part 1 and part 2, respectively. In part 1 these included dyspnea, arthralgia, and a grade 5 tracheoesophageal fistula, and in part 2 included diarrhea, pneumonitis, nephritis, fatigue, respiratory failure, and heart failure in one patient each, and fatigue in three patients.
Grade 2 radiation pneumonitis was seen in two patients in each group, Dr. Lin of the University of Texas MD Anderson Cancer Center, Houston, said at the meeting, which was sponsored by the International Association for the Study of Lung Cancer.
Withdrawals caused by toxicity occurred in three and four patients in part 1 and 2, respectively.
Four patients in part 1 progressed with disease during atezolizumab maintenance and five have died from either tracheoesophageal fistula or grade 5 toxicity. In part 2, six have progressed and five have died, most caused by cancer progression, he said.
Preliminary survival data show a median progression-free survival of 20.1 months in part 1, whereas progression-free survival was not reached in part 2. Median overall survival at 1 year was 60% versus 77% in parts 1 and 2, respectively.
Consolidation immunotherapy with durvalumab after CRT has been the standard of care for LA-NSCLC as established by the phase 3 PACIFIC trial, but evidence from that trial also suggested timing of the start of immunotherapy may be important.
“If patients were randomized less than 14 days after starting durvalumab there was a trend, or suggestion, that there was potentially an improvement in progression-free survival, compared with patients who started durvalumab outside of this window,” Dr. Lin said, noting that this is also supported by some preclinical evidence showing that the effectiveness of immunotherapies may be enhanced when combined with concurrent CRT.
The DETERRED trial evaluated the safety and preliminary efficacy of this approach followed by consolidation full-dose carboplatin/paclitaxel with atezolizumab and maintenance atezolizumab for up to 1 year for LA-NSCLC.
Patients, who had a median age of 66.5 years, were enrolled between February 2016 and April 2018; 15% had stage II disease, 50% had stage IIIA, and 35% had stage IIIB. Most (58%) had adenocarcinoma.
In part 1, standard chemoradiation including low-dose carboplatin/paclitaxel was given for 6 weeks. After CRT completion, patients were given consolidated high-dose chemotherapy with carboplatin/paclitaxel and intravenous atezolizumab was started at that point at a dose of 1,200 mg every 3 weeks for up to 1 year from the first dose. Part 2 was initiated based on the safety data in part 1 showing no concerning toxicities. In part 2, atezolizumab was given concurrently with CRT followed by the same consolidated regimen and maintenance.
“So the take-home message from this study is that the concurrent immunotherapy with atezolizumab and chemoradiation therapy can be administered safely,” Dr. Lin said, adding that grade 3+ pneumonitis is low and not significantly increased with the addition of concurrent atezolizumab with CRT.
Early efficacy analyses also show promising results, but further follow-up is needed, he said.
Trials now being planned include a phase 3 trial comparing the DETERRED and PACIFIC regimens, a phase 1 study comparing durvalumab with radiation to replace chemotherapy in programmed death–ligand 1–high locoregionally advanced NSCLC, and a phase 1 study of nivolumab with radiation to replace chemotherapy in locoregionally advanced NSCLC, he noted.
The DETERRED trial was supported by Genentech. Dr. Lin has received research grants from STCube Pharmaceuticals, Hitachi Chemical Diagnostics, Genentech, New River Labs, and BeyondSpring Pharmaceuticals, and is an advisory board member for AstraZeneca and New River Labs.
SOURCE: Lin SH et al. WCLC 2018, Abstract OA01.06.