A JZP341 Study in Adult Participants With Advanced or Metastatic Solid Tumors

This study will assess the safety and efficacy of JZP341 in participants with advanced or metastatic solid tumors.

This is a first-in-human, open-label, multiple-dose, phase 1, multicenter, dose-finding study of single-agent JZP341 followed by a targeted expansion phase.

This study will have 2 phases: Dose Finding Phase and Dose Expansion Phase.

The Dose-Finding Phase will determine the recommended phase 2 dose (RP2D), assess safety and pharmacokinetics/pharmacodynamics, and explore preliminary antitumor activity of JZP341 in participants with relapsed or refractory advanced solid tumors.

The Dose-Expansion Phase will evaluate clinical activity and further evaluate the safety of multiple doses of single-agent JZP341 at the RP2D in participants with relapsed or refractory colorectal adenocarcinoma.

Eligibility Criteria:
Inclusion Criteria:

* Signed informed consent form (ICF)
* ≥ 18 years of age at the time of signing the ICF
* Eastern Cooperative Oncology Group performance status of 0 to 2
* Adequate bone marrow reserve
* Adequate coagulation function, liver/pancreas function, and renal function
* No clinically significant abnormalities in the levels of serum electrolytes
* Life expectancy \>12 weeks
* Male participants are eligible to participate if they agree to the following during the study intervention period and for at least 3 months after the last dose of study intervention:

  * Refrain from donating sperm, AND either:
  * Be abstinent from heterosexual intercourse as their preferred and usual lifestyle and agree to remain abstinent, OR
  * Must agree to use an approved contraception method
* A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:

  * Woman of non-childbearing potential (WONCBP)
  * Woman of childbearing potential (WOCBP) and using an effective contraceptive method
* A WOCBP must have a negative highly sensitive pregnancy test within 72 hours of the first dose of study intervention

Inclusion Criteria for Dose Finding Phase Only:

* Have a histologically or cytologically confirmed diagnosis of advanced or metastatic solid tumor that has progressed after prior standard therapy, been intolerant to or is ineligible for standard therapy, or has a malignancy for which there is no approved therapy considered standard of care

Inclusion Criteria for Dose Expansion Phase Only:

* Histologically or cytologically confirmed colorectal adenocarcinoma that has progressed on or is intolerant to treatment from fluoropyrimidine, oxaliplatin, and irinotecan. Participants may have received bevacizumab, anti-epidermal growth factor receptor monoclonal antibody, or checkpoint inhibitor as appropriate.
* Measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 criteria

Exclusion Criteria:

* Primary central nervous system (CNS) tumor or symptomatic CNS metastases that are neurologically unstable or have required increasing doses of steroids within the 4 weeks prior to study entry to manage CNS symptoms (symptomatic brain metastases that have been adequately treated are not excluded)
* Any clinically significant cardiac disease defined as New York Heart Association class III or IV within the 6 months before Screening
* History of ≥ Grade 3 pancreatitis
* History of intracranial thrombosis or history of recurrent thrombosis (except for catheter-related thrombosis)
* Active (significant or uncontrolled) gastrointestinal bleeding
* Active uncontrolled infection (≥ Grade 2) at the time of enrollment
* HIV-positive, unless:

  * CD4+ count ≥ 300/μL;
  * Undetectable viral load; AND
  * Receiving highly active antiretroviral therapy
* Uncontrolled infection of hepatitis B or hepatitis C or diagnosis of immunodeficiency

  * Participants with Hepatitis B who have controlled infection are permitted. Participants with controlled infections must undergo periodic monitoring of Hepatitis B virus DNA. Participants must remain on antiviral therapy for ≥ 6 months beyond the last dose of study intervention.
* Pregnant (or plan to be pregnant) or lactating woman
* History of any severe or uncontrolled medical condition
* Unresolved toxicity, based on the investigator's assessment of the participant, from prior radiation, chemotherapy, or other targeted treatment, including investigational treatment, except for stable conditions ≤Grade 2 (ie, neuropathy, myalgia, fatigue, alopecia, therapy-related endocrinopathies)
* Prior treatment with JZP341 or any other asparaginase