The study was terminated based on a business decision by the Sponsor.

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.

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