Amivantamab plus chemotherapy produced a median overall survival of 34.3 months in the final analysis of the Phase 3 PAPILLON study, the longest reported median OS in EGFR exon 20 insertion-positive non-small cell lung cancer and roughly twice the historical median of 16 to 24 months for this mutation subtype. That number lands against a backdrop where amivantamab first reached patients in this setting via accelerated approval in 2021, in the second line, based on single-arm data. PAPILLON represents the randomized, first-line confirmation of how far that trajectory has moved.
The six-month gain over the chemotherapy-alone arm (27.9 months) is harder to dismiss than the raw hazard ratio suggests. The protocol-specified analysis returned an HR of 0.87, which did not meet statistical significance, but 76 percent of eligible patients in the control arm crossed over to amivantamab after progression. A prespecified crossover-adjusted analysis cut the risk of death by 43 percent (HR 0.57; nominal p=0.003). That crossover rate also tells its own story: investigators were willing to use the combination drug as salvage in the majority of control patients, which compresses any survival separation in the unadjusted result. Twelve percent of patients in the combination arm remained on first-line treatment at the data cutoff; none in the chemotherapy arm did.
The durability signal extends beyond OS. Progression-free survival through second disease progression ran 28.3 months with the combination versus 17.5 months with chemotherapy alone, a difference of more than 10 months (HR 0.59; nominal p<0.0001). That PFS2 measure captures benefit beyond the first progression, including whatever second-line therapy patients received, and the gap holding at more than 10 months suggests the combination's advantage is not simply front-loaded. Safety was consistent with earlier reports: paronychia and neutropenia each appeared in 60 percent of patients, rash in 58 percent, with no new signals at longer follow-up. Data were presented at the IASLC 2026 World Conference on Lung Cancer Presidential Symposium.
EGFR exon 20 insertions account for roughly 12 percent of all EGFR mutations in NSCLC, a population that has historically carried a five-year survival rate of just eight percent. The PAPILLON OS data now give prescribers a randomized, final-analysis survival number to anchor first-line decisions. The figure to watch as this matures is whether the crossover-adjusted HR of 0.57 holds up to regulatory scrutiny as a basis for labeling updates, since that adjusted analysis carries more clinical weight than the headline result every time a payer or guideline committee asks whether the six-month unadjusted difference justifies the combination’s toxicity profile.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
