In this study, people will take a medicine called S241656 by mouth. They may take it by itself or with other cancer treatments, and they may take it once or twice a day depending on their study group. The study has two parts. In Part 1, people receive different amounts of the medicine so researchers can find the safest dose. In Part 2, people receive the safest dose that was found in Part 1. Participants will keep taking the medicine until their cancer gets worse or the side effects become too strong or happen too often.

During the study, they will visit the clinic regularly and have many tests, including blood tests, urine tests, and scans. The whole study is expected to last about five years.

KRAS, BRAF, and Other RAS/MAPK Mutation-Positive Neoplasms

People can join this study if they are 18 years or older and have advanced or metastatic cancer with certain gene changes, such as KRAS, HRAS, NRAS, BRAF, or CRAF mutations. They must not be able to have surgery to remove their cancer and must have already tried at least one other treatment.

The purpose of this study is to find out if the medicine S241656 can help treat cancers that have certain changes, called mutations, in genes such as KRAS, BRAF, or other RAS genes.