Clarification was provided to the inclusion criterion on contraception. In addition, reporting for serious adverse events and adverse events of special interest has been extended to 90 days after last dose of study treatment or until initiation of a new anti-cancer therapy, whichever occurs first. Palliative radiotherapy has also been clarified to only be permitted after the induction phase with chemotherapy is complete.

Clarification has been added regarding tumor assessments for patients who are randomized to atezolizumab. The contraception requirement for female patients for 6 months after the last dose of cisplatin was added. The contraception requirement for male patients for 6 months after the last dose of cisplatin, carboplatin, and gemcitabine was added. The study inclusion criteria have been modified to allow for patients with treated, asymptomatic cerebellar metastases to be enrolled provided specific criteria are met. The exclusion criteria for history of autoimmune disease has been broadened to allow for patients with eczema, psoriasis, lichen simplex chronicus, or vitiligo with dermatologic manifestations only to be permitted provided that they meet the specific conditions. The study exclusion criterion regarding treatment with systemic immunostimulatory agents within 4 weeks or five-half lives of the drug (whichever is shorter) prior to randomization has been modified to 4 weeks prior to randomization for consistency with more recent atezolizumab protocols. The exclusion criterion specifying that patients with a history of allergic reaction to intravenous contrast that requires steroid pretreatment should have baseline and subsequent tumor assessments performed via magnetic resonance imaging (MRI) has been removed. Patients with contraindications to contrast may have assessments done with non-contrast computed tomography or MRI. The use of any live vaccine has been updated to be prohibited within 90 days following the administration of the last dose of atezolizumab in addition to 28 days prior to and during study treatment with atezolizumab.

Clarification has been added that a wash-out period of at least 4 weeks or five half-lives, whichever is longer, of any systemic immunostimulatory agent is required prior to randomization.

Option for erlotinib switch maintenance was removed for patients randomized to Arm B of the study. The following assessments for evaluation of study treatment have been removed due to Sponsor's decision to close enrollment into study GO29432 and to enroll patients with squamous NSCLC into the ongoing study GO29431: pharmacokinetic, biomarker, anti-therapeutic antibody, tumor tissue sampling, patient-reported outcome assessments, and survival follow-up. Objectives, endpoints, assessments noted above, and associated statistical analyses have been removed as they are no longer relevant. Tumor tissue biopsy at the time of radiographic progression has been made optional. Requirement for independent Data Monitoring Committee reviews have been removed due to the closeout of the study. Study language has been revised to reflect the study's closure to enrollment due to a low number of patients. Use of contraception for female patients treated with atezolizumab has been extended from 90 days to 5 months after the last dose of atezolizumab, and female patients treated with atezolizumab should be instructed to inform the investigator of any pregnancy that occurs during study treatment and within 5 months after the last dose of atezolizumab. Hormone replacement therapy or oral contraceptive have been removed from the exclusion criteria. Hormonal therapy with gonadotropin-releasing hormone agonists or antagonists for prostate cancer have been removed from the list of permitted therapy. Traditional herbal medicines have been removed from prohibited therapy, and language has been added to state that concomitant use of herbal therapies is not recommended because the pharmacokinetics, safety profile, and drug-drug interactions are unknown. However, use of herbal therapies not intended for the treatment of cancer for patients in the study is allowed at the discretion of the investigator.