Key Inclusion Criteria:

- Histological or cytological confirmation of LMS arising at any anatomic site except
bone sarcoma, unresectable or metastatic, relapsed or refractory disease measurable
per RECIST 1.1 criteria

- Disease progression on previous treatment before screening or intolerability to other
oncology treatments

- Participants with liver metastases may be enrolled

- Participants with well-controlled asthma or chronic obstructive pulmonary disease may
be enrolled.

- Toxicity from prior therapies recovered to Grade ≤1 or participant's baseline, except
for alopecia. In addition, endocrinopathies associated with prior immunotherapy-based
treatments that are well controlled on replacement medication are not exclusionary.

- At least 1 prior systemic cytotoxic or targeted therapy regimen for LMS

- At least 4 weeks since prior surgery and recovered in the opinion of investigator

Key Exclusion Criteria:

- Received temozolomide or dacarbazine at any time

- Any other systemic anticancer therapy including investigational agents ≤ 3 weeks before
initiation of study treatment. Additionally, participants may not have received
radiation ≤ 3 weeks before initiation of study treatment.

- Known intolerance to dacarbazine or one or more of the excipients in unesbulin.

- Co-existing active infection or any co-existing medical condition likely to interfere
with study procedures

- Gastrointestinal disease or other conditions that could affect absorption. Active
peptic ulcer disease or previous history of gastric perforation within the last 2
years

- Major surgery, open biopsy, or significant traumatic injury that has not recovered, in
the opinion of the investigator, within 28 days of baseline

- Prior malignancies, other than LMS, that required treatment or have shown evidence of
recurrence (except for non-melanoma skin cancer or adequately treated cervical
carcinoma in situ, prostate cancer in situ or any other low risk malignancy that is
approved by the medical monitor) during the 5 years before initiation.

- Prior or ongoing clinically significant illness, medical or psychiatric condition,
medical history, physical findings, electrocardiogram (ECG) findings, or laboratory
abnormality that, in the investigator's opinion, could affect the safety of the
participant, or alter the absorption, distribution, metabolism, or excretion of the
study drugs, or could impair the assessment of study results.

Note: Other inclusion and exclusion criteria may apply.

Eligibility last updated 4/12/22. Questions regarding updates should be directed to the study team contact.