The study treatment, BAY 3713372, is under development to treat MTAP (methylthioadenosine phosphorylase)-deleted solid tumors. It is thought to work by blocking the protein arginine N-methyltransferase 5 (PRMT5). This may kill the MTAP-deleted cancer cells while sparing the normal cells.

The main objective of this first-in-human study is to learn how safe BAY 3713372 is, how the body processes it, and how well it works in people with MTAP-deleted solid tumors.

For this, the researchers will study and analyze:

• the number of participants who have adverse events (AEs) after receiving different doses of BAY 3713372 and the AE's severity.
• the number of participants who experience dose-limiting toxicities (DLTs) after receiving different doses of BAY 3713372, the DLT's severity and how often they happened. A DLT is a pre-defined medical problem caused by a specific dose of a drug that is too severe to continue using that dose.
• the total amount of BAY 3713372 in participants' blood (also called AUC) over time after single and multiple doses.
• the highest level of BAY 3713372 in participants' blood (also called Cmax) after single and multiple doses.

Other than the main objective, researchers will also check for the number of participants who show a response to treatment and how long they live without the cancer getting worse.

The study participants will take part in one of the eight distinct groups or "intervention cohorts" of the study. The study will start with a dose escalation phase where distinct groups of participants will receive different doses of BAY 3713372 alone to find the dose that is deemed safe and works best for the participants. When this dose has been found, a larger number of participants will receive BAY 3713372 alone or with other treatments in a dose expansion phase.

Participants may take the study treatment as long as they benefit from the treatment without any severe medical problems.

Participants will visit the study site:

• at least twice before the treatment starts
• multiple times when they start taking the treatment
• once after 30 days of receiving the last dose and every 9 weeks after that until the cancer worsens, or the participant stops for any other reason

During the study, the doctors and their study team will:

• check participants' health by performing tests such as blood and urine tests, and checking heart health using an electrocardiogram
• check if the participants' cancer has grown and/or spread using computed tomography (CT) or magnetic resonance imaging (MRI) and, if needed, bone scan
• take tumor samples

The study doctors and their team will contact the participants every 3 months until 2 years after the last participant's last dose or the end of the study to learn about the participant's health.

Inclusion Criteria:

• Participant must be ≥ 18 years old of age, or the legal age of consent in the jurisdiction of the country in which the study takes place, at the time of signing the informed consent.
• At least one measurable lesion that would qualify as target lesion by Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST 1.1).
• Homozygous MTAP-deletion identified through molecular testing from a locally certified laboratory.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

Exclusion Criteria:

• Previous additional cancer other than the one evaluated in this study within the past 2 years except for basal or squamous cell carcinoma of the skin, carcinoma in situ of the cervix, superficial bladder tumors, localized prostate cancer or other tumors that in the opinion of the investigator, are considered cured or not immediately life-threatening, and will not interfere with the scientific goals of this study.

• A marked prolongation of QT/QTc interval at screening (e.g., repeated demonstration of a QTc interval >450 ms). Participants with permanent pacemakers (i.e., a paced rhythm) may be eligible based on the investigator's clinical assessment and discretion.

• Cardiac history comprising:

  • History of congestive heart failure Class >II according to the New York Heart Association Functional Classification.
  • Myocardial infarction less than 6 months before the start of study intervention.
  • Serious cardiac arrhythmias requiring treatment or any clinically important abnormalities in rhythm, conduction or morphology on resting ECG with the exception of atrial fibrillation which is well-controlled and requires only digoxin or beta blockers.

• Unstable angina within 4 weeks before start of study intervention.

Availability of this study's data will later be determined according to Bayer's commitment to the EFPIA/PhRMA "Principles for responsible clinical trial data sharing". This pertains to scope, timepoint and process of data access. As such, Bayer commits to sharing upon request from qualified researchers patient-level clinical trial data, study-level clinical trial data, and protocols from clinical trials in patients for medicines and indications approved in the US and EU as necessary for conducting legitimate research. This applies to data on new medicines and indications that have been approved by the EU and US regulatory agencies on or after January 01, 2014. Interested researchers can use www.vivli.org to request access to anonymized patient-level data and supporting documents from clinical studies to conduct research. Information on the Bayer criteria for listing studies and other relevant information is provided in the member section of the portal.