Bayda Pharmaceutical BPI-16350 confirmed ORR up to 60.5%

The 59th Annual meeting of the American Society of Clinical Oncology (ASCO) was held June 2-6 in Chicago. Data from a Phase I clinical study of BPI-16350 in patients with HR+/HER2- advanced metastatic breast cancer was presented at the conference in abstract form, with a confirmed ORR of up to 60.5% and good safety.

Abstract number: e13051

Special Session: Metastatic Breast Cancer

Key points: This is an open, dose-escalation and dose-expansion phase I study to evaluate the safety, pharmacokinetic profile and initial antitumor activity of BPI-16350 monotherapy (phase A) and in combination with fluvestran in patients with HR+/HER2- advanced metastatic breast cancer (stage B).

● As of November 13, 2022, A total of 24 patients (50mg,n=4; 100mg,n=4; 200mg,n=3; 300mg,n=3; 400mg,n=4; 500mg,n=6), including 23 patients with advanced breast cancer and 1 patient with abdominal liposarcoma, receiving 50-500mgqdbPI-16350 monotherapy. In stage B, a total of 46 patients with HR+/HER2- advanced metastatic breast cancer received BPI-16350(300mg, n=9; 400mg, n=37) combined with fluvestran, 63.0% (29/46) of the patients remained in the treatment group.

● Efficacy: In stage A, the disease control rate (DCR) reached 70.8% (17/24). One patient (4.2%) in the 500mg dose group achieved partial response (PR). In stage B, 43 of 46 patients were evaluated at least once, with a DCR of 97.7% (42/43), a confirmed ORR of 60.5% (26/43), and a median PFS not yet reached.

● Safety: In stage A, only one DLT event of grade 3 creatinine elevation was observed in the 500mg dose group, and MTD was not achieved. Grade 3 or greater adverse events occurred in 45.8% (11/24) of patients, the most common being diarrhea (4/24), anemia (3/24), and neutropenia (2/24). At stage B, 42.5% (20/46) of patients had grade 3 or greater adverse events, the most common being anemia (8/46), leukopenia (6/46), hypokalemia (6/46), and neutropenia (5/46).

●PK characteristics: The median peak time of BPI-16350 ranges from 2.0 to 17.0 hours, and the average half-life ranges from 35.6 to 51.0 hours. Bpi-16350 can be administered once a day. After a single oral dose of 50~500 mgBpi-16350, the drug exposure was proportional to the dose. After continuous administration of QD, the accumulation ratio was 2.1-3.3 times.

● Conclusions: Compared with approved CDK4/6 inhibitors, BPI-16350 combined with fluvestran shows numerically superior antitumor activity [1-4] and a lower incidence of grade ≥3 diarrhea than abesili, as reported in previous studies.