PRIMARY OBJECTIVE:~I. To determine the safety and efficacy of grapiprant and eribulin combination treatment for the patient with metastatic inflammatory breast cancer (mIBC).~SECONDARY OBJECTIVES:~I. To determine objective response rate (ORR), % of the patients who achieve complete response (CR) or partial response (PR).~II. To determine the time to progression (TTP) of the proposed treatment. III. To determine the duration of response of the proposed treatment. (Phase 2 only) IV. To determine the time to first response of the proposed treatment. (Phase 2 only) V. To determine progression-free survival (PFS) of the proposed treatment. VI. To determine the overall survival (OS) of the proposed treatment. VII. To investigate the predictive biomarker of the proposed treatment.~EXPLORATORY OBJECTIVE:~I. To evaluate the changes in the tumor microenvironment after the proposed treatment.~OUTLINE:~Patients receive grapiprant orally (PO) twice daily (BID) on day 1-21 and eribulin mesylate intravenously (IV) over 5 minutes on days 1 and 8. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity.~After completion of study treatment, patients are followed up at 30 days, then yearly for up to 5 years.
This phase Ib/II trial tests the safety and side effects of grapiprant and eribulin and whether they work to shrink tumors in patients with inflammatory breast cancer that has spread to other places in the body (metastatic). Grapiprant is an anti-inflammatory drug that may prevent tumor growth. Eribulin may block tumor cell growth by stopping tumor cell division. Giving grapiprant and eribulin together may help to control the disease.