Clinical Trial Finder

Inclusion Criteria:

1. Males and females greater than or equal to 18 years of age. 2. Life expectancy of at least 3 months. 3. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0, 1 or 2. 4. Histopathologically confirmed diagnosis of PCNSL (medical record is acceptable). Cerebral biopsies are not required if imaging reveals typical images of PCNSL. 1. Participants with parenchymal lesions must have unequivocal evidence of disease progression (e.g., presence of at least 1 measurable target lesion [≥ 10 millimeters (mm) and ≤ 40 mm in the longest diameter on brain magnetic resonance imaging [MRI] or head computed tomography [CT] on imaging within 28 days prior to Cycle 1 Day 1]). In cases where the tumor size is smaller but still measurable and located at a critical central nervous system (CNS) location, disabling the participant and/or causing symptoms, this participant may be eligible following a discussion with the Sponsor Medical Monitor. 2. For participants limited to leptomeningeal involvement, cerebrospinal fluid (CSF) analysis (cytology and/or flow cytometry) with or without additional imaging (MRI) of the spine as clinically indicated is required to document abnormal cells within 28 days prior to Cycle 1 Day 1. Exclusion Criteria for Part B and Part C. 1. Participants with only intraocular PCNSL without brain lesion or CSF involvement, T-cell lymphoma, systemic presence of lymphoma, or non-CNS lymphoma metastatic to the CNS. 2. Evidence of systemic lymphoma. This must be demonstrated by a positron emission tomography (PET) scan (or CT scan with contrast if applicable) of the chest, abdomen, and pelvis at Screening (testicular ultrasound may be considered to exclude a testicular lymphoma disseminated to the brain). 3. Prior history of malignancies other than lymphoma (except for basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix or breast) or prior history of systemic lymphoma, unless the participant has been free of the disease for ≥ 3 years. 4. Active malignancy other than PCNSL requiring systemic therapy. 5. Previous BTKi treatment (Part C only). 6. History of Grade ≥ 3 rhabdomyolysis without complete recovery. 7. Requirement for urgent therapy due to uncontrolled tumor mass/edema effects. 8. Received external beam radiation therapy to the CNS within 28 days prior to Cycle 1 Day 1. 9. Received prior investigational drugs (including treatment in clinical research, unapproved combination products, and new dosage forms) within 28 days or 5 half-lives, whichever is shorter, prior to Cycle 1 Day 1; allogeneic hematopoietic stem cell transplant (HSCT) within 60 days prior to Cycle 1 Day 1; or had clinically significant graft-versus-host disease (GVHD) requiring ongoing up-titration of immunosuppressive medications prior to Screening (with the exception of a BTKi for Part B only). Note: The use of a stable or tapering dose of immunosuppressive therapy post-HSCT and/or topical steroids for ongoing skin GVHD is permitted with Sponsor Medical Monitor approval. 10. Any prior systemic anti-cancer treatment such as chemotherapy, immunomodulatory drug therapy, etc., received within 14 days or 5 half-lives, whichever is shorter, prior to Cycle 1 Day 1 (with the exception of ibrutinib or other BTKi for Part B only, which may be continued until the day before Cycle 1 Day 1) 11. Prior history of hypersensitivity or anaphylaxis to emavusertib, ibrutinib or any of their excipients.

Arms

Experimental: Emavusertib (CA-4948) dose escalation

Part A1: Dose-level cohorts with up to approximately 6 participants each will be used to define the Maximum Tolerated Dose (MTD) for emavusertib.

Experimental: Emavusertib (CA-4948) and ibrutinib dose escalation

Part A2: Evaluate escalating dose levels of oral emavusertib in combination with 560 mg QD or 420 mg QD of oral ibrutinib. The starting dose of emavusertib to be used in combination will be 200 mg BID. It is anticipated that 12 to 20 participants at a potential dose level will be required to establish optimal combination dosing.

Experimental: Emavusertib (CA-4948) and ibrutinib dose expansion

In two Expansion Cohorts (Part B), emavusertib in combination with ibrutinib will be administered in participants with R/R PCNSL who have progressed on a BTKi. In Cohort 1, emavusertib 100 mg BID will be administered with ibrutinib 560 mg QD consecutively in 28-day treatment cycles. In Cohort 2, emavusertib 200 mg BID will be administered with ibrutinib 560 mg QD consecutively in 28-day treatment cycles.

Experimental: Emavusertib (CA-4948) and ibrutinib

In this part of the study (Part C), eligible second-line participants with R/R PCNSL who are naïve to BTKi treatment will receive 1 of 3 treatment arms: (1) emavusertib 200 mg BID, (2) ibrutinib 560 mg QD, or (3) emavusertib 200 mg BID in combination with ibrutinib 560 mg QD. Treatments will be administered continuously in 28-day treatment cycles.

Interventions

Drug: - Emavusertib

Emavusertib will be provided as a tablet dosage form to be taken BID.

Drug: - Ibrutinib

Ibrutinib will be provided as a tablet or capsule dosage form to be taken QD.