Each participant will undergo a screening period, a treatment period, and a follow-up period. Participants will be followed until death, withdrawal of consent, or end of study, whichever occurs first.
During the treatment period, participants will receive SNB-101 (dose range: 5 mg/m2 to 50 mg/m2) intravenously on day 1 and day 15 of each 28 day cycle.
Dose reductions are permitted after the DLT observation period, which occurs during the first 28 days of treatment (cycle 1). Participants may permanently or temporarily (at the investigator's discretion) discontinue SNB-101. If a participant experiences a DLT or unacceptable toxicity, SNB-101 treatment should be interrupted until the observed toxicity returns to baseline or ≤ grade 1 toxicity. The start of the next cycle can be delayed up to 2 weeks at the investigator's discretion.