This study is for people with a specific type of brain cancer called MGMT methylated glioblastoma. It looks at whether adding a drug called lomustine to the usual treatment of temozolomide and radiation can help fight the cancer better. Temozolomide and lomustine are chemotherapy drugs that work by damaging the DNA in cancer cells to stop them from growing. Radiation therapy uses high-energy x-rays to kill cancer cells.

Participants will be randomly put into two groups. One group will get the usual treatment with temozolomide and radiation. The other group will get lomustine in addition to the usual treatment. The study checks to see if the added treatment helps patients live longer or keeps the cancer from growing.

• The study lasts for about 6 cycles, with each cycle lasting 28 or 42 days, depending on the group.
• Participants will have regular MRI scans to check their progress.
• Participants will be monitored every few months after treatment ends.