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Phase 1/2 study of AVZO-023 drug combination in patients with advanced cancer

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The trial involves adults with Advanced Cancer that has spread and cannot be cured with standard surgery. It tests a new oral tablet called AVZO-023 either by itself or together with another tablet, AVZO-021, and sometimes with hormonal medicines such as the injection Fulvestrant or the pill Letrozole. An oral tablet is a pill taken by mouth, while an injection is placed into a muscle.

The purpose of the study is to determine the safety, appropriate dose, and early signs that the drugs can shrink tumors. Participants will start with a low dose that is gradually increased, take the medication daily for a cycle of about four weeks, and attend regular clinic visits for physical exams, blood tests, and scans that show tumor size.

The study is divided into an early part that looks for side‑effects and the highest dose people can tolerate, followed by a later part that evaluates whether the combination can produce tumor shrinkage. The total time in the study may last several months, depending on how the individual responds and any side effects.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Start of Treatment (Day 1)

    AVZO-023 is taken as a tablet taken by mouth on the first day after you have joined the study.

    If your treatment plan includes additional drugs, you will also receive AVZO-021 (oral tablet), letrozole (2.5 mg oral tablet), and/or fulvestrant (injection into the muscle).

  2. Step 2

    Taking Study Medication

    You will take the prescribed study tablets each day according to the schedule given by the study team. The exact amount and how often you take each tablet are determined by the study protocol.

    If you receive fulvestrant, it will be given as an injection into a muscle; the timing of each injection follows the study schedule.

  3. Step 3

    Monitoring During First Cycle

    During the first treatment cycle you will have regular visits for safety checks, including blood tests, vital‑sign measurements, and an electrocardiogram (ECG) to monitor heart activity.

    Any side effects you experience will be recorded and evaluated by the study staff.

  4. Step 4

    Dose Escalation Evaluation (Phase 1)

    In Phase 1 the study aims to find the highest dose of AVZO-023 that can be given safely, either alone or together with the other drugs.

    Based on the safety information from the first cycle, the dose may be increased for the next cycle if it is considered safe.

  5. Step 5

    Continue Treatment or Adjust Dose

    If the dose is tolerated, you will continue taking the same medication schedule in subsequent cycles.

    If side effects are too severe, the dose may be reduced or the medication may be paused according to the study guidelines.

  6. Step 6

    Dose Expansion Phase (Phase 2)

    When a suitable dose has been identified, the study moves to Phase 2, where more patients receive the same dose to evaluate how well the treatment works against the tumor.

    You will continue the same medication regimen while the study assesses tumor response using imaging criteria (RECIST v1.1).

  7. Step 7

    Ongoing Assessments and End of Study

    Throughout the study you will have periodic visits for safety monitoring, blood tests, and imaging to check tumor size.

    The study will end for you when the predefined treatment period is completed, the disease progresses, or an unacceptable side effect occurs.

Who can join the trial?

6 criteria

  • Age: You must be 18 years old or older at the time of screening.
  • ECOG performance status of 0‑1 (a simple scale that measures how well you can carry out daily activities) and a life expectancy of more than 3 months.
  • Having HR+/HER2‑ breast cancer that is confirmed by tissue testing (looked at under a microscope) and is either locally advanced or has spread (metastatic).
  • Measurable disease as judged by the doctor using RECIST v1.1 criteria (standard way to measure tumor size on scans). Bone‑only disease is allowed during the dose‑escalation part of the study.
  • Willingness to provide a molecular test report and allow use of stored tumor samples or a fresh biopsy if needed.
  • Having sufficient renal (kidney), liver, and bone‑marrow function (laboratory tests showing these organs are working well).

Who cannot join the trial?

11 criteria

  • You must not have taken any previous experimental drugs that block CDK enzymes (such as CDK2, CDK4, or CDK2/4/6 inhibitors), which are medicines that try to stop cancer cells from growing.
  • You cannot have a past problem called drug‑induced pneumonitis or interstitial lung disease, which are types of lung inflammation or scarring caused by medication.
  • You must not have a confirmed loss‑of‑function mutation or deletion of the Rb1 gene, a gene that helps control how cells grow.
  • You cannot have active cancer that has spread to the brain (brain metastasis) or to the membranes covering the brain and spinal cord (leptomeningeal disease), whether untreated or showing new or worsening lesions on scans.
  • You cannot have another current invasive cancer, or a previous invasive cancer that was treated less than three years ago, except for well‑treated skin cancers (basal cell or squamous cell), carcinoma in situ, or harmless colon polyps.
  • Your most recent cancer treatment must have ended at least two weeks ago (four weeks for biologic, immunotherapy, or antibody‑drug conjugate ADC treatments) or at least five drug half‑lives before the first study dose, whichever comes first.
  • You must not have had major surgery within four weeks before the first study dose.
  • You cannot have received limited‑field radiation for symptom relief within seven days of the first study dose, unless it was whole‑brain radiation that finished at least four weeks earlier, and you must be fully recovered from any radiation side effects, not need steroids, and have no active radiation‑related lung inflammation.
  • You must not be taking strong or moderate CYP3A4 inhibitors or inducers (medicines that change how the study drug is broken down) within two weeks or five drug half‑lives before the first dose, whichever is shorter.
  • You cannot have a serious heart or blood‑vessel problem (cardiovascular condition) that occurred within the past six months.
  • You must not have any lingering side effects from previous therapy that are worse than mild (Grade 1 on the CTCAE v5.0 scale), except for hair loss (alopecia), skin color loss (vitiligo), or mild‑to‑moderate nerve problems (peripheral neuropathy up to Grade 2).
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Investigated drugs

  • AVZO-023

    is an experimental oral tablet being tested for the first time in humans. In this study it is given alone to see if it is safe, and also together with other medicines to find out whether it can help shrink tumors in people with advanced solid cancers. The drug is taken by mouth and researchers are looking at how the body processes it and how it affects the cancer.

  • AVZO-021

    is another experimental oral tablet that is studied alongside AVZO-023. It is also taken by mouth and is combined with AVZO-023 (and sometimes with hormone‑blocking therapy) to see if the two drugs work better together to control tumor growth. The trial is checking its safety and how it interacts with the other treatments.

  • Fulvestrant

    (brand name Faslodex) is an approved hormone therapy that is injected into a muscle. It works by blocking and destroying estrogen receptors, which can slow the growth of cancers that need estrogen to grow. In this trial it is used as a background treatment, meaning all participants receive it in addition to the study drugs to see how the new medicines work together with standard hormone therapy.

  • Letrozole

    is an approved oral tablet that belongs to a class of drugs called aromatase inhibitors. It reduces the amount of estrogen the body makes, which can help control cancers that rely on estrogen. In this study, letrozole is given to participants as a background endocrine therapy, allowing researchers to evaluate the new drugs when combined with a commonly used hormone‑lowering medication.

What is already known about the treatment

  • AVZO-023

    This investigational drug is taken by mouth as a tablet. It is currently in early clinical testing and has not yet been approved or widely reported in medical literature. The study is evaluating it for use in patients with advanced solid tumors, where it is expected to help stop tumor growth. It works by binding to a specific protein that cancer cells need to grow, and it is classified as an experimental anticancer agent.

  • AVZO-021

    This experimental medicine is also administered orally in tablet form. It is in the same early‑phase research stage as AVZO‑023 and is not yet approved for any indication. The trial is testing it together with AVZO‑023 and hormone therapies for advanced cancers, aiming to improve tumor control. It is thought to interfere with a signaling pathway that drives cancer cell survival and is categorized as an investigational anticancer drug.

  • Fulvestrant

    Fulvestrant is given by injection into the muscle as a clear solution. It is an approved medicine that has been studied for many years and is used to treat hormone‑sensitive breast cancer. It works by binding to estrogen receptors and causing them to be broken down, which stops estrogen‑driven tumor growth. Pharmacologically, it is classified as a selective estrogen receptor degrader (SERD).

  • Letrozole

    Letrozole comes in film‑coated tablets that are swallowed. It is an established, approved drug that has been widely used for hormone‑dependent breast cancer. The medication blocks the enzyme aromatase, lowering estrogen levels in the body and thereby slowing the growth of estrogen‑sensitive tumors. It belongs to the class of drugs known as aromatase inhibitors.

Investigated diseases

Advanced cancer - Advanced cancer refers to a stage of malignant disease in which the tumor has grown beyond its original location and may have spread to nearby tissues or distant organs. As the disease progresses, cancer cells continue to multiply and can invade surrounding structures, causing swelling or obstruction. The spread of cancer cells to other parts of the body is called metastasis and can involve lymph nodes, bone, liver, lungs, or brain. Over time, the tumor burden may increase, leading to worsening symptoms such as pain, fatigue, or organ dysfunction. The disease course is characterized by gradual enlargement of existing lesions and the appearance of new metastatic sites.
Trial detailsLast updated 31 Oct 2026
Age18+ yearsPhasePhase ITrial ID2026-525948-15-00Protocol codeAVZO-023-1001Estimated enrolment380 patientsSponsorAvenzo Therapeutics Inc.

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