RecruitingPhase 2Drug trialPhase II Trial of Amivantamab Plus Monochemotherapy in Platinum Unfit NSCLC Patients With EGFR exon20 Insertion Mutations.To assess safety and efficacy of amivantamab plus monochemotherapy in terms of ORR, PFS and OS in subjects with EGFR exon20 insertion mutations metastatic non-small cell lung cancer unfit for platinum-based chemotherapy.