Carboplatin, Etoposide, and Atezolizumab With or Without Trilaciclib (G1T28), a CDK4/6 Inhibitor, in Extensive-Stage SCLC

Study Overview
=================
Brief Summary
-----------------
This was a study to investigate the potential clinical benefit of trilaciclib (G1T28) in preserving the bone marrow and the immune system, and enhancing antitumor efficacy when administered with carboplatin, etoposide, and atezolizumab (E/P/A) therapy in first line treatment for patients with newly diagnosed extensive-stage SCLC. The study was a randomized, double-blinded, placebo-controlled design. Approximately, 100 patients were randomized to trilaciclib + E/P/A or placebo + E/P/A in the study.

Detailed Description
-----------------
The posted results represent the final results from Study G1T28-05, a Phase 2 study of carboplatin, etoposide, and atezolizumab with or without trilaciclib (G1T28) in patients with untreated extensive-stage small cell lung cancer (SCLC). The final myelopreservation efficacy results are from database lock 1 (data cut-off [DCO] 17 Aug 2018). The final anti-tumor efficacy data (BOR, DOR, PFS) are from a second database lock 2 (DCO 28 June 2019) that occurred to support the trilaciclib New Drug Application (NDA). Final overall survival and safety data are reported from the final study database lock (DCO 11 Dec 2020, last patient last visit date of 29 October 2020). Please note the last patient last visit date description above which is recorded as the study completion date. Following the last patient last visit, the final database lock occurred a few weeks later which accounts for the discrepancy between the study completion date and the reported assessment time frames.

Official Title
-----------------
Phase 2 Study of Carboplatin, Etoposide, and Atezolizumab With or Without Trilaciclib in Patients With Untreated Extensive-Stage Small Cell Lung Cancer (SCLC)

Conditions
-----------------
Small Cell Lung Cancer

Intervention / Treatment
-----------------
* Drug: Trilaciclib
* Drug: Placebo
* Drug: Carboplatin
* Drug: Etoposide
* Drug: Atezolizumab


Participation Criteria
=================
Eligibility Criteria
-----------------
Key Inclusion Criteria: Male or female subjects aged ≥18 years Unequivocally confirmed diagnosis of SCLC by histology or cytology, preferably including the presence of neuroendocrine features by immunohistochemistry Extensive-stage SCLC At least 1 target lesion that is measurable by Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 Adequate organ function Eastern Cooperative Oncology Group (ECOG) performance status of 0 - 2 Predicted life expectancy of ≥3 months Able to understand and sign an informed consent Exclusion Criteria: Limited-stage SCLC Prior chemotherapy for limited or extensive-stage SCLC Prior treatment with immunotherapies including but not limited to cluster of differentiation 137 agonists or immune checkpoint blockade therapies (such as anti-programmed cell death protein 1 (PD-1), anti-programmed death-ligand 1(PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) therapeutic antibodies). Presence of symptomatic brain metastases requiring immediate treatment with radiation therapy or steroids. Malignancies other than SCLC within 3 years prior to randomization, with the exception of those with negligible risk of metastasis or death treated with expected curative outcome History of idiopathic pulmonary fibrosis, organizing pneumonia, drug induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan Active, known, suspected autoimmune disease requiring systemic treatment in the past 2 years Uncontrolled ischemic heart disease or uncontrolled symptomatic congestive heart failure Known history of stroke or cerebrovascular accident within 6 months prior to enrollment Serious active infection at the time of enrollment Psychiatric illness/social situations that would limit study compliance Other uncontrolled serious chronic disease or conditions that in the investigator's opinion could affect compliance or follow-up in the protocol Known human immunodeficiency virus, known active hepatitis B, or hepatitis C Radiotherapy to any site or radiotherapy within 2 weeks prior to enrollment Receipt of any investigational medication within 4 weeks prior to enrollment Administration of attenuated vaccine within 4 weeks before enrollment or anticipation that such a live attenuated vaccine will be required during the study Influenza vaccination should be given during influenza season only (approx. Oct to March). Patients must not receive live, attenuated influenza vaccine (eg, FluMist) within 4 weeks prior to enrollment at any time during the study, and at least 5 months after the last dose of atezolizumab. Patients with a condition requiring systemic treatment with either corticosteroids ( > 10 mg daily prednisone equivalents) or other immunosuppressive medications (including but not limited to cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor agents) within 14 days of study drug administration. Inhaled or topical steroids ad adrenal replacement dosed > 10 mg daily prednisone equivalents are permitted in the absence of active autoimmune disease. Hypersensitivity to any of the components of the formulation of etoposide or etoposide phosphate Hypersensitivity to carboplatin or other platinum-containing compounds or to mannitol History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins Known hypersensitivity to Chinese hamster ovary cell products or other recombinant human antibodies Legal incapacity or limited legal capacity Pregnant or lactating women

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: trilaciclib+etoposide/carboplatin/atezolizumab<br>Induction: Patients received trilaciclib 240 mg/m² administered intravenously (IV) once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was administered on Day 1 of each 21-day cycle using the Calvert formula with a target area under the concentration-time curve (AUC) = 5 milligrams per milliliter per minute (mg/mL/min) to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity or discontinuation by the patient or investigator. | Drug: Trilaciclib<br>* Trilaciclib IV<br>* Other names: G1T28;Drug: Carboplatin<br>* Carboplatin IV<br>* Other names: Paraplatin;Drug: Etoposide<br>* Etoposide IV<br>* Other names: VP-16;Drug: Atezolizumab<br>* Atezolizumab IV<br>* Other names: Tecentriq;|
| Experimental: placebo+etoposide/carboplatin/atezolizumab<br>Induction: Patients received placebo administered IV once daily prior to E/P/A on Days 1, 2 and 3 of each 21-day E/P/A therapy cycle (up to 4 cycles in total). Etoposide 100 mg/m² was administered IV daily on Days 1, 2, and 3 of each 21-day cycle. Carboplatin was be administered on Day 1 of each 21-day cycle using the Calvert formula with a target AUC = 5 mg/mL/min to calculate the dose. Atezolizumab 1200 mg was administered as an IV infusion on Day 1 of each 21-day cycle. Maintenance: Following the induction phase, patients received maintenance atezolizumab at a dose of 1200 mg on Day 1 of every 21-day cycle until disease progression, unacceptable toxicity or discontinuation by the patient or investigator. | Drug: Placebo<br>* Placebo IV<br>Drug: Carboplatin<br>* Carboplatin IV<br>* Other names: Paraplatin;Drug: Etoposide<br>* Etoposide IV<br>* Other names: VP-16;Drug: Atezolizumab<br>* Atezolizumab IV<br>* Other names: Tecentriq;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of Severe (Grade 4) Neutropenia in Cycle 1 | Duration of severe neutropenia (DSN; days) was defined as the number of days from the date of the first absolute neutrophil count (ANC) value of <0.5 × 10⁹/L observed between start of cycle and end of cycle to the date of the first ANC value ≥0.5 × 10⁹/L that met the following criteria: (1) occurred after the ANC value of <0.5 × 10⁹/L and (2) no other ANC values <0.5 × 10⁹/L occurred between this day and end of cycle. DSN was set to 0 for patients who did not experience severe neutropenia in a cycle, including those that were randomized and not treated. Data from unscheduled visits and the actual assessment date (rather than visit date) were included in the derivation. | Evaluated for Cycle 1 of the Induction Period (i.e., from randomization to the end of Cycle 1, each cycle = 21 days). | 
| Number of Participants With at Least 1 Occurrence of Severe (Grade 4) Neutropenia | The occurrence of severe (Grade 4) neutropenia (SN) was a binary variable. If a patient had at least 1 absolute neutrophil count value <0.5 × 10^9/L during the Induction Period, the patient was assigned as Yes to the occurrence of SN; otherwise, it was No. | Induction Period. From date of randomization, 21 day treatment cycles up to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| All-Cause Dose Reductions | Dose reductions are not permitted for trilaciclib or atezolizumab. Dose reductions for E/P are derived from changes in the protocol-specified dose on the dosing page and correspond to the reductions for toxicity specified in the protocol. No more than 2 dose reductions of E/P in total were allowed for any patient. Simultaneous reduction in the doses of etoposide and carboplatin were counted as 1 dose reduction. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of RBC Transfusion on/After Week 5 (Proportion of Patients) | For this endpoint, the occurrence during the Induction Period was defined as a binary variable (Yes or No); Yes, if total number of events ≥1 was observed, No for other scenarios. If a patient did not have an event, a value of 0 was assigned to that patient. Each red blood cell transfusion with a unique start date on/after Week 5 on study during the Induction was defined as a separate event. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 374 days. | 
| Occurrence of Granulocyte Colony-Stimulating Factor (G-CSF) Administration (Proportion of Patients) | For this endpoint, the occurrence during the Induction Period was defined as a binary variable (Yes or No); Yes, if total number of events ≥1 was observed, No for other scenarios. If a patient did not have an event, a value of 0 was assigned to that patient. Any G-CSF administration in a cycle during the Induction Period was defined as a separate event. A patient with at least 1 cycle with G-CSF administration during an induction cycle or the Induction Period was considered to have occurrence of G-CSF administration. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Overall Survival (OS) | Overall survival was calculated as the time (months) from date of randomization to the date of death due to any cause. Patients who did not die during the study were censored at the date last known to be alive. Patients lacking data beyond the date of randomization had their survival time censored at date of randomization. Overall survival was not censored if a patient received other anti-tumor treatments after the study drugs. Overall survival was calculated using the Kaplan-Meier method. | From date of randomization to date of death due to any cause, assessed up to a maximum of 38.1 months. | 
| Major Adverse Hematologic Events (MAHE) (Composite Endpoint) | The composite endpoint major adverse hematologic events (MAHE) included the following aspects of myelosuppression: All-cause hospitalizations - Each recorded preferred term (PT) with a unique start date was counted as an event. All-cause dose reductions - Dose reductions were permitted for E/P but not for trilaciclib or atezolizumab. No more than 2 dose reductions were allowed. Each dose reduction was counted as a separate event. Febrile neutropenia-Each febrile neutropenia event with a unique start date during the Induction Period was defined as a separate event. Prolonged severe neutropenia (SN)-Each cycle with a severe neutropenia duration greater than 5 days was counted as an event, with the date of the first Grade 4 laboratory value defined as the start date for the time-to-first event analysis. Red blood cell (RBC) transfusion on/after Week 5-Each RBC transfusion with a unique start date on/after Week 5 on study during the Induction Period was defined as a separate event. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Best Overall Response | For all patients, the Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) tumor response data were used to determine each patient's visit response (TPR = time point response). Per RECIST v1.1 for target lesions and assessed by CT/MRI: Complete Response (CR), Disappearance of all target lesions; Partial Response (PR), >=30% decrease in the sum of the longest diameters of target lesions; Progressive Disease (PD), >=20% increase in the sum of the longest diameter of target lesions, Stable Disease, neither sufficient shrinkage or increase to quality for PR or PD. Objective Response Rate (ORR) = CR + PR. The TPR at each visit was determined in 2 ways: (1) derived programmatically at the time of analysis using the information from target lesions, non-target lesions, and new lesions based on data collected through eCRF; and (2) judged by the investigator as collected in the eCRF. Results shown here are from the programmatically derived assessments. | From date of randomization, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 724 days. | 
| Duration of Objective Response (Complete Response or Partial Response) | Duration of Response (DOR) is the time between first response by RECIST Version 1.1 of CR or PR and the first date that progressive disease is documented by RECIST Version 1.1, or death. Patients who do not experience PD or death will be censored at the last tumor assessment date. Only those patients with confirmed responses will be included in this analysis. | From date of randomization, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 724 days. | 
| Progression-Free Survival | Progression-free survival (PFS) was defined as the time (number of months) from date of randomization until date of documented radiologic disease progression per RECIST v1.1 or death due to any cause, whichever came first. | From date of randomization, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 724 days. | 
| Number of Participants With at Least 1 Occurrence of Febrile Neutropenia | The criterion for identifying febrile neutropenia was if the preferred term for an adverse event was FEBRILE NEUTROPENIA. Any occurrence of a febrile neutropenia event during the induction treatment period is defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. Each febrile neutropenia event with a unique start date during the induction treatment period was defined as a separate event. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of Grade 3 or 4 Hematologic Laboratory Abnormalities | The occurrence of Grade 3 and 4 hematologic toxicities was a binary endpoint. If a patient had at least 1 cycle with at least 1 Grade 3 or 4 hematologic toxicities during the Induction Period, the patient was assigned as Yes to the occurrence of Grade 3 and 4 hematologic toxicities; otherwise, it was No. If a patient did not have an event, the value of 0 was assigned to that patient. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of Erythropoiesis Stimulating Agent (ESA) Administration | Any ESA administration in a cycle during the Induction Period was defined as a separate event. A patient with at least 1 cycle with ESA administration during an induction cycle or the Induction Period was considered to have occurrence of ESA administration. The criterion to select proper records was as follows: If the chemical subgroup from WHO-DD Version September 2017 (ie TEXT4 for CODE4) takes the value OTHER ANTIANEMIC PREPARATIONS, the medication was classified as ESAs. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of Platelet Transfusion | Any occurrence of a platelet transfusion during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. Each platelet transfusion event with a unique start date during the induction treatment period was defined as a separate event. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of Infection Serious Adverse Events (SAEs) | Any occurrence of an infection SAE during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. The criterion for identifying the proper infection SAE records was as follows: if the system organ class (SOC) from Medical Dictionary for Regulatory Activities (MedDRA) Version 20.1 takes value INFECTIONS AND INFESTATIONS, and the AE was a serious event. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of Pulmonary Infection Serious Adverse Events (SAEs) | Any occurrence of a pulmonary SAE during the induction treatment period was defined as a binary variable (Yes or No); Yes if total number of febrile neutropenia events ≥ 1 is observed, No for other scenarios. If the patient did not have an event, the value of 0 was assigned to that patient. Each pulmonary infection SAE with a unique start date during the induction treatment period was defined as separate event. The criterion for identifying the proper pulmonary infection SAE records was as follows: The SOC from MedDRA Version 20.1 took the value INFECTIONS AND INFESTATIONS, the adverse event was a serious event, and the PT took values from the following list of PTs under the category of pulmonary infection adverse events: bronchiolitis, bronchitis, infectious pleural effusion, influenza, pneumonia, pneumonia bacterial, respiratory tract infection, upper respiratory tract infection, and viral upper respiratory tract infection. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With at Least 1 Occurrence of IV Antibiotic Uses | Occurrence of an IV antibiotics administration during the induction treatment period is defined as a binary variable (Yes or No); Yes if total number of IV antibiotics administration ≥ 1 is observed, No for other scenarios. Each IV antibiotic with a unique start date during the induction treatment period will be defined as a separate event. The criteria for identifying an IV antibiotic administration event was (1) if the therapeutic subgroup from WHO-DD Version September 2017 (ie, TEXT2 for CODE2) takes the value ANTIBACTERIALS FOR SYSTEMIC USE, and (2) the route of medication was intravenous or the route was other with the detailed specification as IVPB. | Induction Period. From date of randomization, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Duration of Study Drug Exposure (Induction Period and Maintenance Period) | Induction period duration of exposure (days) = Day 1 of last induction cycle - Cycle 1 Day 1 of induction phase + 21. Maintenance period duration of exposure (days) = Day 1 of the last maintenance cycle -Cycle 1 Day 1 of maintenance phase + 21. | From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1162 days. | 
| Number of Cycles Completed (Induction Period and Maintenance Period) | Patients were considered to have started a cycle if they have received at least one dose of any study drug (carboplatin, etoposide, atezolizumab or trilaciclib). | From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 49 cycles. | 
| Relative Dose Intensity of Trilaciclib/Placebo, Carboplatin, Etoposide, Atezolizumab (Induction Period) and Atezolizumab (Maintenance Period) | Relative dose intensity is defined as 100% times the actual dose intensity divided by the planned dose intensity. The planned dose intensity is defined as the cumulative planned dose through the study divided by (number of cycles * 3 weeks) | From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 724 days. | 
| Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Induction Period) | After Cycle 1, patients need to meet pre-specified laboratory parameter criteria before initiating Cycle 2 and each subsequent cycle of chemotherapy. A Cycle Day Status page asks if the cycle was delayed. If the start of the current cycle was delayed (the site answers Yes), this will be counted as a delay. Cycle delays could occur for management of toxicity (hematologic or non-hematologic) or for administrative/logistic reasons. The reason for each cycle delay was captured in the eCRF if it was related to AEs. Reasons other than AEs were not captured. | Induction Period. From date of first dose, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With Any Cycle Delays and the Number of Cycles Delayed (Maintenance Period) | After Cycle 1, patients need to meet pre-specified laboratory parameter criteria before initiating Cycle 2 and each subsequent cycle of chemotherapy. A Cycle Day Status page asks if the cycle was delayed. If the start of the current cycle was delayed (the site answers Yes), this will be counted as a delay. Cycle delays could occur for management of toxicity (hematologic or non-hematologic) or for administrative/logistic reasons. The reason for each cycle delay was captured in the eCRF if it was related to AEs. Reasons other than AEs were not captured. | Maintenance Period. From date of first maintenance dose, 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1160 days. | 
| Number of Participants With Any Missed Doses [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) | Missed doses are identified on the dosing page of each study drug based on the question Was the dose given?. The missed dose information will be obtained for each study drug. For a study drug, if the last record of response to question Was the dose given? is No, it will not be considered as a missed dose but instead considered to be end of treatment if both criteria below are met: (1) No other study drugs are given on the same day, and (2) No study drugs are given subsequently. | Induction Period. From date of first dose, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With Any Missed Doses of Atezolizumab (Overall Treatment Period) | Missed doses are identified on the dosing page of each study drug based on the question Was the dose given?. The missed dose information will be obtained for each study drug. For a study drug, if the last record of response to question Was the dose given? is No, it will not be considered as a missed dose but instead considered to be end of treatment if both criteria below are met: (1) No other study drugs are given on the same day, and (2) No study drugs are given subsequently. | From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1162 days. | 
| Number of Participants With Any Dose Interruptions [for Each Study Drug: Trilaciclib/Placebo, Carboplatin and Etoposide] (Induction Period) | Dose interruptions were defined as interruption of infusion, regardless of whether the study drug was continued after the interruption. | Induction Period. From date of first dose, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 
| Number of Participants With Any Interrupted Doses of Atezolizumab (Overall Treatment Period) | Dose interruptions were defined as interruption of infusion, regardless of whether the study drug was continued after the interruption. | From date of first dose, up to four 21-day cycles of Induction therapy, followed by 21 day cycles of Maintenance therapy until disease progression, unacceptable toxicity or discontinuation by the patient or investigator, assessed up to 1162 days. | 
| Number of Participants With Any Dose Reductions of Carboplatin and Etoposide (Induction Period) | No dose reductions were allowed for trilaciclib or atezolizumab during the study. | Induction Period. From date of first dose, 21 day treatment cycles to a maximum of 4 cycles or until (if earlier) disease progression, unacceptable toxicity, or discontinuation by the patient or investigator, assessed up to a maximum of 409 days. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Small Cell Lung Cancer, CDK4/6 Inhibitor, Immune Checkpoint Inhibitor