The protocol was amended in response to a health authority request. The exclusion criterion related to history of prior malignancy other than lymphoma was updated, second primary malignancies were included as events immediately reportable to the Sponsor, and the Schedule of Assessments was updated to include urinalysis and a complete physical examination on Cycle 1 Day 1.

Obinutuzumab exposure data was updated to reflect the latest information from clinical studies. It was clarified that atezolizumab could be given on Day 15 of induction Cycles 2 to 6 regardless of cytopenia. Based on the latest atezolizumab Investigator’s Brochure (IB; version 9), the summary of clinical safety, summary of clinical activity, the use of live vaccines after discontinuation of atezolizumab, management guidelines for non-hematologic AEs, and the list of AESIs were updated. In addition, the classification of diabetes mellitus and pancreatitis changed from ‘important potential risks’ to ‘important identified risks’.

The classification of second malignancies was changed from a selected AE to AESI to more closely monitor this AE. In addition, conditions for resuming study treatment in case of Grade >=3 laboratory abnormalities were clarified, and the list of AESIs for atezolizumab were updated to align with the latest Atezolizumab IB (version 9).

On 3 July 2017, two clinical trials, KEYNOTE-183 and KEYNOTE-185, evaluating pembrolizumab (PD-1 inhibitor) in combination with an immunomodulatory agent (pomalidomide or lenalidomide) for the treatment of multiple myeloma were placed on clinical hold by the U.S. Food and Drug Administration (FDA). The clinical hold was issued because interim results demonstrated a worse overall survival in the investigational pembrolizumab arm compared to the control arm. Based on these emerging data, on 1 September 2017 the FDA also requested that other studies of PD-1/PDL-1 inhibitors and immunomodulatory agents, including study BO29562 should be placed on partial clinical hold. Although study BO29562 is conducted in a different hematologic malignancy (i.e., relapsed or refractory follicular lymphoma) and a similar safety signal has not been seen to date, the Sponsor revised the protocol to maximize patient safety. FDA removed the partial clinical hold as of 21 November 2017. Changes to the protocol, along with a rationale for each change: 1) Available Clinical Data was updated with the most recent efficacy and safety data. Stopping rules for excess toxicity and the roles of the IMC were updated, and the frequency of interim safety and efficacy analyses were amended to occur every 4 months; 2) Risks associated with obinutuzumab were updated to reflect recent updates to the obinutuzumab IB (version 12); 3) Risks associated with atezolizumab and management guidelines for atezolizumab-associated AEs were updated according to updates to the atezolizumab IB (version 10).

Protocol was amended to include new safety information: 1) Lists of risks for atezolizumab and guidelines for managing patients who experience atezolizumab-associated adverse events were revised to include nephritis; 2) Considering no new safety signals have been identified with atezolizumab in combination with obinutuzumab plus lenalidomide, once all patients have completed/discontinued maintenance, regular Internal Monitoring Committee assessments would no longer take place and ad hoc meetings maybe called at the discretion of the Medical Monitor in case of newly identified safety signals; 3) Post-trial access language was changed allowing patients still under study treatment to enter an extension study in case of earlier closure of Study BO29562; 4) The Medical Monitor information was updated; 5) The Lenalidomide Summary of Product Characteristics has replaced local labels as the reference document for determining reporting requirements for single adverse events

The protocol was amended to include new saftey information: 1) Background information on atezolizumab was revised to include the additional approved indications; 2) List of risks was updated to include myositis; 3) "Immune-related" was changed to "immune-mediated" when describing events associated with atezolizumab; 4) Language was added to clarify that, after withdrawal of consent for participation in the Roche Clinical Repository (RCR), remaining RCR samples were destroyed or were no longer linked to the participant; 5) To address a request by the French National Agency for the Safety of Medicines and Health Products, language regarding atezolizumab risks was revised to remove the description and management guidelines for systemic immune activation and added descriptions and management guidelines for hemophagocytic lymphohistiocytosis and macrophage activation syndrome; 6) Language was revised to account for the fact that some sites did not allow follow-up on partner pregnancies; 7) Language was updated to indicate that therapeutic or elective abortions were not considered AEs unless performed because of an underlying maternal or embryofetal toxicity; 8) Language was added for consistency with Roche's current data retention policy and to accommodate more stringent local requirements (if applicable); 9) Language was added to indicate that the study would comply with applicable local, regional, and national laws; 10) Language was revised to clarify that redacted Clinical Study Reports and other summary reports would be made available upon request; 11) Appendix 7 (Anaphylaxis Precautions) was modified to remove the requirement for use of a tourniquet; 12) Guidelines for managing participants who experienced atezolizumab-associated AEs was provided in Appendix 10.