Efficacy and Safety Comparison of Obinutuzumab-Venetoclax vs. Obinutuzumab-Chlorambucil in Untreated CLL with Comorbidities

The primary objective of this study is to determine the **efficacy** of a combined regimen of obinutuzumab and venetoclax compared with obinutuzumab and chlorambucil (GClb) in previously untreated patients with **Chronic Lymphocytic Leukemia (CLL)** who have coexisting medical conditions. This is assessed by investigator-assessed progression-free survival (PFS), which is a critical measure in evaluating the effectiveness of cancer treatments, as it indicates the length of time during and after treatment that a patient lives with the disease without it getting worse.

Secondary objectives include:

• Determining efficacy through additional outcome measures, including PFS assessed by an Independent Review Committee (IRC), overall response, complete response, and minimal residual disease (MRD) response rate as measured by allele-specific oligonucleotide polymerase chain reaction (ASO-PCR).
• Evaluating the safety of the combination of obinutuzumab and venetoclax compared with GClb, focusing on the nature, frequency, and severity of Grade 3 and 4 adverse events and serious adverse events.
• Characterizing the pharmacokinetics of venetoclax and obinutuzumab, including population pharmacokinetics (pop-PK) techniques.
• Comparing disease and treatment-related symptoms following treatment with the combination of obinutuzumab and venetoclax compared with GClb, as measured by the M.D. Anderson Symptom Inventory (MDASI-CLL).
• Evaluating changes in role functioning and global health status/quality of life (QoL) following treatment with the combination of obinutuzumab and venetoclax compared with GClb, as measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30).
• Comparing the health utility effects of treatment with the combination of obinutuzumab and venetoclax compared with GClb, as measured by the EuroQol 5 Dimension questionnaire (EQ-5D-3L).

The clinical trial involves a total of **130 participants** diagnosed with **Chronic Lymphocytic Leukemia (CLL)**. The study population includes both male and female subjects, with an age range primarily encompassing older adults. Participants were selected based on specific criteria, including documented previously untreated CLL and a requirement for treatment according to the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria. The trial targets individuals with coexisting medical conditions, as indicated by a Total Cumulative Illness Rating Scale (CIRS) score greater than 6 or a creatinine clearance (CrCl) of less than 70 mL/min. Participants are required to have adequate marrow and liver function and a life expectancy of more than six months. The trial does not include a vulnerable population, and lifestyle factors such as diet and physical activity are not specified as part of the selection criteria.

The clinical trial is designed as a **randomized**, open-label, multicenter Phase III study to evaluate the efficacy and safety of a combined regimen of **obinutuzumab** and **venetoclax** compared to obinutuzumab and **chlorambucil** in patients with previously untreated **Chronic Lymphocytic Leukemia (CLL)** and coexisting medical conditions. The primary objective is to assess progression-free survival (PFS) as determined by the investigator using the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria. Secondary endpoints include overall survival, objective response rate, and incidence of adverse events, among others. The trial is expected to conclude by August 2025, with recruitment having commenced in February 2015.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as documented untreated CLL, a Cumulative Illness Rating Scale (CIRS) score greater than 6, and adequate liver and marrow function. Following randomization, participants will attend regular follow-up visits to monitor treatment response and safety. The end-of-study visit will assess the final outcomes and any long-term effects of the treatment. The expected duration of participant involvement is up to 336 days, depending on the treatment arm and individual response.

Conditions that may lead to early termination from the study include disease progression, unacceptable toxicity, or withdrawal of consent. The trial employs a robust methodology to ensure the reliability of results, with assessments conducted according to established clinical guidelines. The study's design and procedures are structured to provide comprehensive data on the comparative efficacy and safety of the treatment regimens, contributing valuable insights into the management of CLL in patients with additional health challenges.

The clinical trial involves the administration of several treatments, including both experimental and non-experimental medications. **Fasturtec** (rasburicase) is provided as a 1.5 mg/ml powder and solvent for concentrate for solution for infusion. It is administered via **intravenous infusion** with a maximum daily dose of 0.2 mg/kg. The treatment period for Fasturtec is limited to one day. This medication is produced by Sanofi Winthrop Industrie and is not a pediatric formulation.

**Venclexta** (venetoclax) is available in the form of film-coated tablets. The maximum daily dose is 400 mg, with a total maximum dose of 117,390 mg over a treatment period of 336 days. The tablets are administered orally. Venclexta is manufactured by AbbVie, Inc. and is designated as an orphan drug. It is used in combination with other treatments in the study.

**Chlorambucil** is provided as 2 mg film-coated tablets, also administered orally. The maximum daily dose is 0.5 mg/kg, with a total maximum dose of 12 mg/kg over a treatment period of 336 days. Chlorambucil is produced by Aspen Pharma Trading Limited and is used as a comparator treatment in the study.

**Gazyvaro** (obinutuzumab) is supplied as a 1,000 mg concentrate for solution for infusion. It is administered via intravenous infusion with a maximum daily dose of 1,000 mg and a total maximum dose of 9,000 mg over a treatment period of 168 days. This medication is manufactured by Roche Registration GmbH and is also designated as an orphan drug. It is re-packaged and re-labelled specifically for clinical trial use.

Participant compliance with the dosing schedules is monitored throughout the trial to ensure adherence to the prescribed treatment regimens. The trial aims to evaluate the efficacy and safety of these combined regimens in patients with chronic lymphocytic leukemia (CLL) and coexisting medical conditions.

The efficacy of the clinical trial will be assessed primarily through **progression-free survival (PFS)**, which is defined as the time from randomization to the first occurrence of progression, relapse, or death from any cause, as assessed by the investigator using the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria. Secondary endpoints include PFS based on independent review committee assessments, objective response rate (ORR), complete response rate, minimal residual disease (MRD) response rate, overall survival (OS), and several other measures of clinical response and survival.

These efficacy parameters will be measured and analyzed at various timepoints throughout the trial. For instance, MRD response rates will be assessed in the peripheral blood and bone marrow at the completion of treatment using allele-specific oligonucleotide polymerase chain reaction (ASO-PCR). The overall response rate will be evaluated at the completion of combination treatment response assessment, which occurs at Cycle 7, Day 1, or 28 days after the last intravenous infusion. The duration of response will be calculated from the first documented overall survival to the time of progressive disease or death. Event-free survival and time to new anti-leukemic treatment will also be tracked from the date of randomization to specific clinical events.