Phase 1a/1b Study of CDK4 Inhibitor BGB-43395 in Metastatic HR+/HER2- Breast Cancer and Advanced Solid Tumors

The primary objective of this study is to evaluate the **safety**, **tolerability**, **pharmacokinetics**, **pharmacodynamics**, and preliminary **antitumor activity** of the CDK4 inhibitor BGB-43395. This investigation is conducted in patients with **metastatic hormone receptor positive (HR+)**/**human epidermal growth factor 2 negative (HER2-) breast cancer** and other advanced solid tumors. Understanding these parameters is crucial for determining the potential therapeutic benefits and risks associated with BGB-43395, which may inform future treatment strategies for these challenging oncological conditions.

The clinical trial involves a total of **59 participants** diagnosed with **advanced or metastatic solid tumors**, including hormone receptor positive (HR+), human epidermal growth factor 2 negative (HER2-) breast cancer. The study population comprises both male and female subjects, with an age range that includes adults and older adults. Participants were selected to include a vulnerable population, although specific criteria for vulnerability are not detailed. The trial does not specify particular lifestyle considerations such as diet or physical activity. The selection process and any additional inclusion or exclusion criteria have not been provided by the sponsor.

The clinical trial is designed to evaluate the **safety**, tolerability, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of the CDK4 inhibitor BGB-43395. This study is conducted in patients with advanced or metastatic solid tumors, including hormone receptor positive (HR+), human epidermal growth factor 2 negative (HER2-) breast cancer. The trial is structured as a Phase 1a/1b study, which is a randomized, double-blind, controlled trial. The estimated recruitment start date is April 1, 2024, with an anticipated end date of May 31, 2026, indicating a total trial duration of approximately two years.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to assess eligibility based on predefined criteria. Following successful screening, participants will be enrolled in the study and will attend regular follow-up visits to monitor their response to the treatment and any potential adverse effects. These visits will include comprehensive assessments such as physical examinations, laboratory tests, and imaging studies as required. The end-of-study visit will occur at the conclusion of the treatment period or upon early termination, where final evaluations will be conducted to gather data on the long-term effects of the treatment.

The expected length of participant involvement will vary depending on individual response to the treatment and the specific phase of the trial in which they are enrolled. Conditions that may lead to early termination from the study include significant adverse reactions, disease progression, or withdrawal of consent by the participant. The trial aims to gather critical data to inform the future development of BGB-43395 as a potential therapeutic option for patients with these advanced cancers.

The clinical trial documentation does not provide specific details regarding the experimental medication, including its name, pharmaceutical form, dosage, route, or frequency of administration. As such, no detailed description of the experimental treatment can be provided based on the available data.

Similarly, there is no information available about any non-experimental treatments used in the study, such as standard-of-care therapy, placebo, or comparator treatment. Consequently, no description of these treatments can be included.

Additional relevant information about drug administration, dosing schedules, and participant compliance monitoring is also not provided in the source data. Therefore, no further details can be offered regarding these aspects of the clinical trial.

The clinical trial is designed to assess efficacy through a structured evaluation process. The trial is categorized as a Phase 1 study, which typically focuses on assessing safety, tolerability, and preliminary efficacy. The trial is scheduled to commence recruitment on April 1, 2024, with an estimated completion date of May 31, 2026. Although specific efficacy endpoints are not detailed, Phase 1 trials often involve the collection of data related to pharmacokinetics and pharmacodynamics, which may include **biomarker** levels or other relevant physiological parameters. The methods for measuring and analyzing these parameters are expected to adhere to standard clinical trial practices, utilizing validated tools and instruments appropriate for the investigational product and the condition under study. The trial will follow a predefined schedule for data collection, ensuring systematic and consistent assessment of efficacy throughout the study duration.