Ceralasertib

Drug Overview

Ceralasertib is an innovative, investigational cancer medicine. It is classified as a Targeted Therapy (often called a “smart drug”). Unlike traditional chemotherapy that attacks all fast-growing cells, targeted therapies look for specific weaknesses inside cancer cells to destroy them.

Here are the key details about this medication:

• Generic Name: Ceralasertib (also known in research as AZD6738).
• US Brand Names: None yet. It is currently an investigational drug used only in clinical trials.
• Drug Class: ATR Kinase Inhibitor / Small Molecule Targeted Therapy.
• Route of Administration: Oral (taken by mouth as a tablet).
• FDA Approval Status: Investigational. It is not yet approved by the FDA for standard public use, but it is being closely studied in clinical trials around the world.

What Is It and How Does It Work? (Mechanism of Action)

Ceralasertib is a Targeted Therapy designed to stop cancer cells from fixing themselves. To understand how it works, we have to look closely at the cell’s DNA.

Every day, the DNA inside our cells gets slightly damaged. Healthy cells have repair systems to fix this damage. Cancer cells also get damaged, especially because they grow and multiply too fast. To survive this constant stress, cancer cells rely heavily on a specific repair protein called ATR (Ataxia Telangiectasia and Rad3-related protein). ATR acts like an emergency brake, stopping the cell from dividing so it has time to fix its broken DNA.

Here is how ceralasertib works at the molecular level:

• Blocking the Repair Protein: Ceralasertib specifically binds to and blocks the ATR protein.
• Cutting the Brakes: Because ATR is blocked, the cancer cell cannot pause to repair its damaged DNA.
• Cell Death: The cancer cell is forced to divide with broken, severely damaged DNA. This massive mistake causes the cell to self-destruct, a process scientists call “mitotic catastrophe.”

This method is highly effective in cancers that already have other broken DNA repair pathways (like ATM or BRCA gene mutations). By taking away their last backup repair system, ceralasertib causes the cancer cells to die while sparing mostly healthy cells—a clever medical strategy called “synthetic lethality.”

FDA-Approved Clinical Indications

Because ceralasertib is still an investigational drug, it does not currently have official FDA-approved indications for everyday clinical use. However, it is being actively tested in clinical trials for the following:

Oncological Uses (In Clinical Trials):

• Non-Small Cell Lung Cancer (NSCLC): Used in combination with immunotherapy to help overcome resistance to past treatments.
• Melanoma: Studied in patients whose skin cancer did not respond to standard immune therapies.
• Advanced Solid Tumors: Tested in breast cancer, ovarian cancer, and stomach cancer, often paired with standard chemotherapy or other targeted drugs.
• Blood Cancers: Investigated for conditions like Chronic Lymphocytic Leukemia (CLL).

Non-oncological Uses:

• None at this time. Ceralasertib is strictly being studied for cancer care.

Dosage and Administration Protocols

Because ceralasertib is still in clinical trials, the exact dose can vary heavily depending on the specific study and what other drugs it is paired with. It is taken as a pill, making it a convenient option that avoids hospital IV infusions.

Clinical Efficacy and Research Results

Recent clinical studies (between 2020 and 2025) have shown both promising results and challenges for ceralasertib as a new treatment option.

• Lung Cancer (NSCLC) Trials: In 2025, a major global Phase III trial called LATIFY tested ceralasertib combined with immunotherapy (durvalumab) against standard chemotherapy. While the combination was safe and well-tolerated, it unfortunately did not improve the overall survival rate compared to standard chemotherapy for these advanced patients.
• Melanoma Success: In early Phase I and II trials, ceralasertib was combined with chemotherapy (paclitaxel) for advanced melanoma patients who stopped responding to prior treatments. The results showed an Objective Response Rate (meaning the tumor significantly shrank) of about 33.3%. The median overall survival in this specific, hard-to-treat group was roughly 7.4 months.
• Overcoming Resistance: Research continues to show that ceralasertib is best used as a team player. By using it alongside other treatments like PARP inhibitors, doctors hope to make highly resistant tumors shrink more effectively.

Safety Profile and Side Effects

Like all cancer treatments, ceralasertib can cause side effects. Because it affects how DNA repairs itself, it mainly impacts normal cells in the body that also grow quickly, like blood cells in the bone marrow.

Black Box Warning: There is no FDA Black Box Warning for this investigational agent yet.

Common Side Effects (>10%):

• Thrombocytopenia: Low blood platelets, which can cause easy bruising or unexpected bleeding.
• Anemia: Low red blood cells, leading to tiredness, paleness, and weakness.
• Neutropenia: Low white blood cells, which increases the risk of getting an infection.
• Fatigue and Nausea: Feeling unusually tired or having a mildly upset stomach.

Serious Adverse Events:

• Severe Bone Marrow Suppression: A severe drop in blood cell counts (Grade 3 or 4 toxicities) that may require a blood transfusion or immediate medical care to prevent dangerous infections.

Management Strategies:

• Doctors will perform regular blood tests to watch your cell counts closely.
• If blood counts drop too low, the medical team will pause the medication for a few days to let your bone marrow recover, or they will lower the daily dose for the next cycle.

Connection to Stem Cell and Regenerative Medicine

While ceralasertib is not a stem cell treatment, it plays an exciting role in the field of Immunotherapy research. Tumors often create a biological “shield” around themselves that suppresses the body’s immune cells. Scientists are studying how ceralasertib acts on the tumor microenvironment to break down this shield. By causing targeted DNA damage inside the tumor, ceralasertib helps wake up the immune system, shifting the area from a suppressed state into a highly activated one. This makes it easier for the body’s natural defenses—and newer immunotherapy drugs—to find and attack the cancer.

Patient Management and Practical Recommendations

To ensure the highest safety during clinical trials, patients must follow specific guidelines while taking ceralasertib.

Pre-treatment Tests to be Performed:

• Complete Blood Count (CBC): To ensure red cells, white cells, and platelets are at safe levels before starting.
• Comprehensive Metabolic Panel: To check that the liver and kidneys are functioning normally to process the drug.
• Pregnancy Test: A negative test is strictly required for women of childbearing age, as the drug can harm an unborn baby.

Precautions During Treatment:

• Because the drug lowers your immune system, avoid crowded places or people who are known to be sick.
• Watch closely for any signs of unusual bleeding, such as bleeding gums when brushing your teeth or unexpected bruising.

“Do’s and Don’ts” List:

• DO take the tablets exactly as directed by your study doctor, at the same times each day.
• DO wash your hands often and practice good hygiene to prevent infections.
• DON’T take any new over-the-counter medicines or dietary supplements without asking your doctor, as they might interfere with the trial drug.
• DON’T ignore a fever. If your temperature goes above 100.4°F (38°C), call your medical team right away, as it could be a sign of a serious infection.

Legal Disclaimer

The information provided in this guide is for educational and informational purposes only and does not constitute medical advice. Ceralasertib is an investigational therapeutic agent and is not currently approved by the US Food and Drug Administration (FDA) for general clinical use. It is available only through participation in approved clinical trials. Always consult with a qualified healthcare professional or your treating oncologist regarding diagnosis, treatment options, and eligibility for clinical trials.