Safety, PK/PD, and Clinical Activity of KT-413 in Adult Patients with Relapsed or Refractory B-cell NHL

Inclusion Criteria:

* Phase 1a Only:

  * Histologically confirmed diagnosis of B-cell NHL according to the 2016 World Health Organization (WHO) classification. Diffuse large B-cell lymphoma (DLBCL) includes: DLBCL not otherwise specified (NOS) with or without MYC and BCL2 and/or BCL6 rearrangements; Epstein-Barr virus (EBV) positive DLBCL, NOS; human herpesvirus 8 (HHV8) positive DLBCL, NOS; DLBCL associated with chronic inflammation; and Primary cutaneous DLBCL, leg type. Patients with indolent lymphoma are eligible if they meet criteria for systemic treatment.
  * Clinicopathological diagnosis of Waldenström's Macroglobulinemia (WM) based on the consensus panel criteria from the Second International Workshop on WM
  * Histologically/cytologically confirmed relapsed/refractory Primary Central Nervous System Lymphoma (PCNSL) by cerebrospinal fluid (CSF) or biopsy. PCNSL patients are considered eligible if the Investigator believes that there is no other reasonable treatment alternative.

    * Note: Patients with HIV-associated PCNSL are not eligible.
    * Note: Patients with secondary CNS metastases are eligible assuming they meet other study criteria. Patients with secondary CNS metastases include those who have synchronous systemic and CNS involvement or those who have been previously treated and relapsed with isolated CNS involvement.
* Phase 1b Only: Histologically confirmed diagnosis of DLBCL according to the 2016 WHO classification including: DLBCL not otherwise specified (NOS) with or without MYC and BCL2 and/or BCL6 rearrangements; Epstein-Barr virus (EBV) positive DLBCL, NOS; HHV8+ DLBCL, NOS; DLBCL associated with chronic inflammation; and Primary cutaneous DLBCL, leg type.
* Disease relapsed and/or refractory to at least 2 accepted standard systemic regimens for all indications except PCNSL. For PCNSL, patients must be relapsed and/or refractory to at least 1 prior regimen.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at Screening.
* Adequate organ and bone marrow function, in the absence of growth factors
* Patients of child-bearing potential must use adequate contraceptive measures to avoid pregnancy for the duration of the study as defined in the protocol

Exclusion Criteria:

* Infection with hepatitis B (HBV), hepatitis C (HCV), or active viral infection with human immunodeficiency virus (HIV).
* Radiation treatment within 4 weeks prior to first dose of study drug, unless the tumor site continues to increase in size after the patient has completed radiotherapy treatment.
* Major surgery requiring general anesthesia within 4 weeks prior to first dose of study drug, unless the tumor site continues to increase in size after the patient has completed radiotherapy treatment.
* Ongoing unstable cardiovascular function including history of myocardial infarction within 3 months of planned start of study drug.
* Patient has not recovered from any clinically significant AEs of previous treatments to pre-treatment baseline or Grade 1 prior to first dose of study drug.