Patient had tumors harboring at least one uncommon mutation (exon 20 insertions [Ins20]: n = 70; T790M: n = 20; G719X: n = 41; L861Q: n = 47; S768I: n = 20; other: n = 25. Of note, 35% of pts had Ins20 mutations, a heterogeneous group generally resistant to EGFR TKIs). In those pts with uncommon mutations and brain metastases, median TTSP and PFS were 7.6 mos (95% CI 4.6–10.1) and 7.4 mos (95% CI 4.6–9.1)....Clinical activity in pts with uncommon mutations was greatest against tumors harboring G719X, L861Q or S768I. Some pts with Ins20 or T790M mutations appeared to benefit from treatment.

...Documented Epidermal Growth Factor Receptor (EGFR) T790M mutation 4....

...A tumor which harbors exon 20 insertion or de novo T790M mutation is eligible for the treatment in the sequential arm 2) Objective clinical benefit from treatment with an Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor (EGFR TKI) as defined by either 1....

...To evaluate the efficiency of castPCR method for detection of resistance genes, especially, T790M mutation from serially collected plasma DNA in non-small cell lung cancer patients harboring EGFR activating mutation who are being treated with EGFR TKIs`detection of resistant gene...

...Time on treatment (TOT) of afatinib as firstline treatment followed by 3rd generation EGFR-TKI in the event of the T790M resistance mutation is developed in patients with EGFR mutation-positive NSCLC...

...Patients were treated with afatinib (Gi(l)otrif®) in the first-line setting and for acquired T790M mutation with osimertinib in the second line; 7....

...- Patients who initiated second-line osimertinib treatment for acquired T790M mutation at least 10 months prior to data entry, AND who were treated with afatinib (Gi(l)otrif®) in the first-line...

...Progression or recurrence of disease after receiving prior continuous gefitinib, afatinib, or erlotinib; A tumor known to harbor a de novo T790M mutation, which is known to confer EGFR TKI resistance....

...L858R, exon 19 deletions, exon 20 insertions, T790M, list is...

...Number of Participants That Have a T790M Mutation on Their Progression Biopsy....

CONTRADICTING EVIDENCE:...the T790M mutation was associated with significantly reduced median PFS (P=0.0005)…

A retrospective cohort study of Chinese patients with metastatic NSCLC harboring EGFR mutations who received first-line gefitinib, erlotinib or afatinib treatment, followed by osimertinib upon disease progression with acquired T790M mutation, was conducted....Patients treated with afatinib in the first-line setting had significantly longer OS compared with those on gefitinib or erlotinib...

Through the last follow-up in May 2021, afatinib and osimertinib demonstrated better progression-free survival (PFS, p < 0.01) and overall survival (OS, p < 0.01) than gefitinib and erlotinib….A total of 44 patients with T790M mutation retained for this study had a mean age of 71 years, and 32 (72.7%) patients were women. All but one patient presented metastatic NSCLC (stage IV)....The ORR and DCR were 31.8% and 52.3%, respectively. Afatinib (ORR 50.0%, DCR 83.3%) and osimertinib (ORR 60.0%, DCR 80.0%) had numerically higher ORR and DCR than gefitinib (ORR 19.0%, DCR 38%) and erlotinib (ORR 16.7%, DCR, 16.7%)...

Uncommon mutation categories were: major uncommon (G719X, L861Q, S768I; 73%); compound (35%); ex20ins (12%); T790M (7%); other (9%). Most pts (n = 226; 92%) were treated in 1st-line with an EGFR TKI; 132 (54%), 70 (28%), 35 (14%) and 7 (3%) received afatinib, gefitinib, erlotinib and osimertinib....Overall median OS was 24.4 mos....ORR was 42% overall (major: 50%; compound: 49%; other: 44%; T790M: 20%; ex20ins: 17%); afatinib: 44% (DoR: 12.0 mos); 1st-gen TKIs: 44% (DoR: 11.0 mos)....Response was highest in pts with major uncommon, and/or compound mutations.

Afatinib is effective in pts with NSCLC with major uncommon and compound EGFR mutations, with broad activity against other uncommon EGFR mutations...Uncommon mutations were classed as: de novo T790M; exon 20 insertions (Ins20); major uncommon mutations (G719X/L861Q/S768I)....Any de novo T790M...ORR 14 (11.7)...mos (95% CI)...17

This pooled analysis assessed afatinib activity in Asian/non-Asian, EGFR TKI-naïve pts with NSCLC and uncommon EGFR mutations, treated in RCTs and real-world studies. Uncommon mutations were classed as: de novo T790M; exon 20 insertions (Ins20); major uncommon mutations (G719X/L861Q/S768I)...Afatinib is effective in pts with NSCLC harboring major uncommon and compound EGFR mutations, with broad activity against other uncommon EGFR mutations and some Ins20 mutations, unaffected by ethnicity.

CONTRADICTING EVIDENCE: This study was a multicenter, single-arm, open-label phase II trial. Treatment-naïve patients with advanced NSCLC positive for common EGFR mutations received afatinib in a dose of 20mg/day….Eight of 19 patients (42.1%) had T790M resistant mutation.

CONTRADICTING EVIDENCE: The allele frequency of the T790M EGFR mutation, a mutation responsible for resistance to EGFR tyrosine kinase inhibitors, was increased after development of afatinib resistance in approximately half of the patients.