A Multicenter, Open-Label Study With a Randomized Control Arm of the Efficacy, Safety, and Pharmacokinetics of Intravenously Infused Berubicin in Adult Patients With Recurrent Glioblastoma Multiforme After Failure of Standard First Line Therapy

• Written informed consent from the patient or their legally authorized representative (LAR) prior to any study-related procedure, and willing and able to comply with the protocol and aware of the investigational nature of this study.

• At least 18 years of age.

• KPS score of ≥ 60

• A confirmed GBM diagnosis must be based on local review of tumor tissue from the initial biopsy, surgery, or re-resection. A formal pathology report confirming GBM is acceptable. It is not a requirement for slides to be sent to a central reviewer.

• Recurrent or progressive GBM as evaluated by central review applying RANO criteria on contrast MRI scans of the Baseline/Screening MRI scan obtained up to six weeks prior to C1D1 and a historical scan taken before the Baseline/Screening scan that meets at least 1 of the following criteria:

∙ In the case of measurable disease, progression will be documented by ≥ 25% increase in the sum of the perpendicular diameter products (SPDPs) of the measurable contrast-enhancing (target) lesions or any new measurable lesions.

‣ If the SPDPs cannot be reliably estimated due to the lesion's complex conspicuity, shape, and contrast enhancement pattern, the volume of all measurable and non-measurable lesions may be used instead, applying the same threshold (≥ 25% increase) to confirm disease progression.

‣ In the case of non-measurable lesions in the historical scan, any transformation into measurable lesions (≥10 mm in both maximum perpendicular diameters) in the Baseline/Screening scan will be evidence of progression.

‣ If there are only non-measurable (non-target) lesions in the Baseline/Screening scan, additional lesions/sites will be considered evidence of progression based on the historical scan. Patients with new cerebrospinal fluid (CSF) seeding will not be considered eligible.

‣ If historical scans are unavailable, a radiology report of a scan taken before the Baseline/Screening scan documenting the SPDPs from a previous scan of the enhancing disease or its volume can be used by the central reviewer to assess eligibility if it demonstrates the quality standards and acquisition guidelines required.

‣ If the scan obtained during standard of care (prior to initiation of formal clinical screening and patient enrollment) is being used as the Baseline/Screening scan and does not entirely conform to central reader quality standards and acquisition guidelines (ie, artifacts or missing sequences), this can be used for the purpose of inclusion if the central reader in discussion with the sponsor and PI agree it provides evidence based on standard clinical practices of recurrence or progression.

‣ Patients at first progression who are treated by re-resection or biopsy to confirm progression do not require measurable disease at their post-operative screening scan as their Baseline/Screening scan. These patients must be medically stable after the procedure as assessed by the PI and have the Baseline/Screening scan available by 7 days before starting treatment.

• The tumor is localized supratentorially with no leptomeningeal (local or distant), spinal or CSF metastases, and no ventricular invasion (explicit documentation of the disease progression that would be problematic in evaluating the efficacy of this drug).

• O\[6\] methylguanine-DNA methyltransferase (MGMT) methylation status must be available; results of routinely used methods for MGMT methylation testing (eg, methylation-specific polymerase chain reaction or quantitative polymerase chain reaction) are acceptable.

• No more than 1 prior line of treatment (eg, surgery followed by radiation with concomitant chemotherapy, followed by adjuvant chemotherapy is considered as 1 line of treatment). In addition, treatment with tumor treating fields (TTFields; Optune) is acceptable if provided as first line therapy prior to progression or recurrence of disease.

• A second debulking surgery, additional radiation or gamma knife surgery during the first line treatment or after progression, and for which the investigator does not suspect pseudoprogression is acceptable, as long as no chemotherapy or immunotherapy has been provided.

⁃ Recovery from toxicity/side effects of all prior therapy to Grade 1 or less, subject to the investigator's discretion, except for alopecia; the following time intervals from previous treatments are required to be eligible:

• 12 weeks from the completion of radiation (to reduce risk of pseudoprogression), unless progression is confirmed by biopsy

∙ 4 weeks from the end of any previous of chemotherapy

∙ 2 weeks from tumor biopsy if wound completely healed

∙ 4 weeks from any major surgery (maximal debulking surgery, either gross total resection or partial resection), gamma knife surgery or significant traumatic injury. Any surgery incisions or wounds must be completely healed

⁃ A stable or decreasing dose of corticosteroids (or none) for brain edema for at least 5 days prior to baseline MRI and enrollment in the study to document disease progression such that changes in the MRI are not related to the use of corticosteroids.

⁃ Eligible for chemotherapy based on adequate bone marrow function and organ function within 2 weeks of study treatment as defined by the following laboratory guidelines, subject to the investigator's discretion:

• Hematopoietic function: total white blood cell (WBC) count ≥3 × 103/µL, absolute neutrophil count (ANC) ≥1.5 × 10³/µL, platelet count ≥75 × 10³/µL, hemoglobin ≥10 g/dL

∙ Hepatic function: bilirubin ≤1.5 × × the upper limit of normal (ULN) (excluding Gilberts Syndrome, for which bilirubin must be ≤4 × ULN); aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \<3 × ULN, and alkaline phosphatase ≤2.5 × ULN

∙ Renal function: serum creatinine ≤1.5 × ULN or for patients with creatinine levels above the ULN, estimated creatinine clearance of ≥60 mL/min, calculated using the Cockcroft-Gault equation35

∙ Activated partial thromboplastin time (aPTT) ≤1.5 × ULN

⁃ Women of childbearing potential must agree to practice a highly effective method of contraception beginning at least 28 days before the start of treatment until at least 6.25 months after the last dose of study drug. Male study patients and their female sexual partners of childbearing potential must agree to practice a highly effective method of contraception starting from the time of informed consent until at least 3.5 months (no less than 104 days) after the last dose of study drug.

• A woman of childbearing potential is defined as a woman who is not permanently sterilized or postmenopausal. Postmenopausal is defined as 12 months with no menses without an alternative medical cause.

∙ Women of childbearing potential must have a negative serum or urine pregnancy test at Screening.

∙ A highly effective method of birth control is defined as one which results in a low failure rate (ie, less than 1% per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some intrauterine devices (IUDs), sexual abstinence, or vasectomized partner. For patients using a hormonal contraceptive method, information regarding all medications being administered to the patient and their potential effects on the contraceptive should be addressed.

⁃ Patients with prior malignancies must be disease-free for ≥5 years. Curatively treated basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix, breast, or bladder; or prostate cancer as well as benign tumors that will not interfere with the treatment plan at the time of screening are allowed.