A Study of Oral MBQ-167 in Participants With Advanced Breast Cancer

Key Inclusion Criteria:

• The investigator will evaluate these and other criteria to determine whether aparticipant can be included in this study.

• Histologically and/or cytologically confirmed advanced breast cancer which hasprogressed after treatment with approved therapies or for which there are nostandard therapies available.

• Participants with known brain metastases may be eligible if specific conditions aremet.

• Life expectancy ≥6 months, in the opinion of the investigator, after startingMBQ-167.

• Are able to swallow capsules twice daily with a meal.

Key Exclusion Criteria:

• The investigator will evaluate these and other criteria to determine whether aparticipant should be excluded from this study.

• Inability to take oral medication, or malabsorption syndrome or any otheruncontrolled gastrointestinal condition (e.g., nausea, diarrhea, or vomiting) thatmight impair the bioavailability of MBQ-167.

• Females who are pregnant or breastfeeding.

• Participants who have received any anticancer treatment within 4 weeks or anyinvestigational agent within 28 days prior to the first dose of trial drug or whohave not recovered from any acute toxicity greater than Grade 0 or 1 related toprevious anticancer treatment.

• Participants who have received any anticancer treatment within 4 weeks or anyinvestigational agent within 28 days prior to the first dose of trial drug or whohave not recovered from any acute toxicity greater than Grade 0 or 1 related toprevious anticancer treatment.

• Active malignancies other than advanced breast cancer will be excluded from thestudy.