Please assess the completion status of the following clinical trial:

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

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE2
- Number of Arms: 2.0

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

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- trilaciclib+etoposide/carboplatin/atezolizumab (Type: EXPERIMENTAL): 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.
- placebo+etoposide/carboplatin/atezolizumab (Type: EXPERIMENTAL): 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.

Based on this trial design, predict the completion outcome and termination type (if applicable).