NCT04585750

Who might be able to join this trial:

• You are at least 18 years old, or between 12 and 17 years old if a special safety committee has given approval.
• You have an advanced or spreading solid tumor cancer that has a specific gene change called a TP53 Y220C mutation.
• You are generally well enough to carry out daily activities with little or no limitation (based on a standard performance scale called ECOG 0 or 1).
• You have already received at least one cancer treatment before, and your cancer has continued to grow or spread since then.
• Your liver, kidneys, and other organs are functioning well enough to safely participate.
• Your cancer can be measured on scans (required for the Phase 2 part of the study).

If you are joining the combination treatment part of the study (Phase 1b), you also need to meet these criteria:

• You have either never received a specific type of immunotherapy (called anti-PD-1/PD-L1 therapy), or you have received it but your cancer continued to progress.
• Your cancer can be measured on scans.

Who may not be able to join:

• You have received cancer treatment within the last 21 days (or within 5 half-lives of that treatment) before starting the study drug.
• You have had radiation therapy within the last 14 days before starting the study drug.
• Your cancer started in the brain or spinal cord (called a primary CNS tumor).
• You have a history of cancer spreading to the lining of the brain or spinal cord, or you have had spinal cord compression.
• You have cancer that has spread to the brain, unless it has been stable for a period of time and you do not need steroids to manage symptoms.
• You have had a stroke or a mini-stroke (TIA) within the past 6 months.
• You have certain heart conditions, including unstable chest pain (angina) in the last 6 months, uncontrolled high blood pressure, a heart attack in the last 6 months, heart failure, abnormal heart rhythm, or an irregular electrical signal in the heart (QT prolongation).
• You have taken certain medications that strongly affect how the liver processes drugs (strong CYP3A4 inducers or strong CYP2C9 inhibitors/inducers) within 14 days of starting the study drug (confirm with trial site).
• You have a history of digestive system problems that may stop your body from absorbing the study drug properly, or you are unable to swallow tablets or capsules.
• You have previously had an organ transplant.
• You have another active cancer (with the exception of certain treated skin conditions or pre-cancerous cervical changes).
• You have an active, uncontrolled infection with Hepatitis B, Hepatitis C, or HIV.

If you are being considered for the Phase 2 part (single drug treatment), you also cannot join if:

• Your cancer has a specific gene change called a KRAS mutation (a type called a single nucleotide variant).

If you are being considered for the combination treatment part (Phase 1b), you also cannot join if:

• You previously received a type of immunotherapy (anti-PD-1, anti-PD-L1, or anti-PD-L2, or similar) and had to stop because of a serious immune-related side effect (Grade 3 or higher).
• You received a live vaccine within the last 30 days before starting the study.
• You have been diagnosed with a weakened immune system, or you have been taking steroid medication regularly within the last 7 days before starting the study.
• You have had a severe allergic reaction (Grade 3 or higher) to the drug pembrolizumab or any of its ingredients.
• You have an autoimmune disease that has needed medical treatment in the past 2 years.
• You have a history of radiation-related lung inflammation (radiation pneumonitis).
• You have a history of, or currently have, lung inflammation or scarring (pneumonitis or interstitial lung disease) that required steroid treatment.
• You currently have an active infection that requires treatment with medication.
• You have a known history of HIV infection.
• You have previously been treated with the study drug rezatapopt.

**Important: Always verify eligibility with the trial site directly before