Study of BGB-290 or Placebo in Participants With Advanced or Inoperable Gastric Cancer

A Phase 2, Double-blind, Randomized Study of BGB-290 Versus Placebo as Maintenance Therapy in Patients With Inoperable Locally Advanced or Metastatic Gastric Cancer That Responded to Platinum-based First-line Chemotherapy

This study enrolled participants with previously-treated advanced or inoperable gastric cancer who have responded to first line platinum therapy into two treatment arms. In Arm A participants received BGB-290; in Arm B participants received placebo. The purpose of this study is to show that BGB-290 (pamiparib) (versus placebo) will improve progression-free survival (PFS) in participants with advanced or inoperable gastric cancer.

This is a double-blind, placebo controlled, randomized multicenter global phase 2 study comparing the efficacy and safety of single agent poly (ADP-ribose) polymerase (PARP) inhibitor BGB-290 to placebo as maintenance therapy in participants with advanced gastric cancer who have responded to first line platinum based chemotherapy. Participants are randomized 1:1 to BGB-290 (Arm A) or placebo (Arm B). Randomization will be stratified by geography, biomarker status, and ECOG performance status.

Participants will undergo tumor assessments at screening and then every 8 weeks, or as clinically indicated. Administration of BGB-290 or placebo will continue until disease progression, unacceptable toxicity, death, or another discontinuation criterion is met.

After end of treatment, long-term follow-up assessments include tumor imaging every 8 weeks for those participants without disease progression, survival status, and new anticancer therapy.

Key Inclusion Criteria:

1. Age ≥ 18 years.
2. Signed informed consent.
3. Histologically confirmed inoperable locally advanced or metastatic adenocarcinoma of the stomach or gastroesophageal junction.
4. Received platinum based first line chemotherapy for ≤ 28 weeks.
5. Confirmed partial response (PR) maintained for ≥ 4 weeks or complete response (CR).
6. Able to be randomized to study ≤ 8 weeks after last platinum dose.
7. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1.
8. Adequate hematologic, renal and hepatic function.
9. Must be able to provide archival tumor tissue for central biomarker assessment.
10. Females of childbearing potential and non-sterile males must agree to use highly effective methods of birth control throughout the course of study and at least up to 6 months after last dosing.

Key Exclusion Criteria:

1. Unresolved acute effects of prior therapy ≥ Grade 2.
2. Prior treatment with PARP inhibitor.
3. Chemotherapy, biologic therapy, immunotherapy or other anticancer therapy ≤ 14 days prior to randomization.
4. Major surgery or significant injury ≤ 2 weeks prior to start of study treatment.
5. Diagnosis of myelodysplastic syndrome (MDS)
6. Other diagnoses of significant malignancy
7. Leptomeningeal disease or brain metastasis
8. Inability to swallow capsules or disease affecting gastrointestinal function.
9. Active infections requiring systemic treatment.
10. Clinically significant cardiovascular disease
11. Pregnant or nursing females.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.