• Male or female, age ≥18.

• Patients with histologically confirmed glioblastoma per 2021 WHO classification progression according to RANO criteria.

• For operated patients, the histological report must document glioblastoma recurrence and a new MRI will need to be done at 3-5 weeks after surgery (directly before study treatment start). Study treatment will need to start minimum 4 weeks after surgery.

• MGMT promotor status known.

• Karnofsky Performance Status (KPS) ≥ 60%.

• Documented negative test for HIV-HBV-HCV. For HBV serology, the determination of HbsAg and anti-HbcAg Ab is required. In patients with serology documenting previous exposure to HBV, negative serum HBV-DNA is required (HBV-DNA is not required for patients with documented vaccination report). For HCV, HCV-RNA or HCV antibody test is required. Subjects with a positive test for HCV antibody but no detection of HCV-RNA indicating no current infection are eligible.

• Female patients: female patients must be either documented not Women Of Childbearing Potential (WOCBP)\* or must have a negative pregnancy test within 14 days of starting treatment.

• Additionally WOCBP must agree to use, from the screening to 6 months following the last study drug administration, highly effective contraception methods, as defined by the Recommendations for contraception and pregnancy testing in clinical trials issued by the Head of Medicine Agencies' Clinical Trial Facilitation Group (www.hma.eu/ctfg.html) and which include, for instance, progesterone-only or combined (estrogen- and progesterone-containing) hormonal contraception associated with inhibition of ovulation, intrauterine devices, intrauterine hormone-releasing systems, bilateral tubal occlusion or vasectomized partner.

• Male patients: male subjects able to father children must agree to use two acceptable methods of contraception throughout the study and until 6 months after last study drug administration (e.g. condom with spermicidal gel). Double-barrier contraception is required.

• Personally signed and dated informed consent document indicating that the subject has been informed of all pertinent aspects of the study.

⁃ Willingness and ability to comply with the scheduled visits, treatment plan, laboratory tests and other study procedures.

‣ Women of childbearing potential (WOCBP) are defined as females who have experienced menarche, are not postmenopausal (12 months with no menses without an alternative medical cause) and are not permanently sterilized (e.g., tubal occlusion, hysterectomy, bilateral oophorectomy, or bilateral salpingectomy).