BeiGene: promising tislelizumab, pamiparib data in lung and ovarian cancer

BeiGene (NASDAQ:BGNE) announces the first reported data from RATIONALE 304, the Phase 3 trial of its anti-PD-1 antibody tislelizumab in combination with chemotherapy as a first-line treatment for patients with locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC), and the data from Phase 2 trial of its investigational PARP inhibitor pamiparib in advanced ovarian cancer (OC) at the European Society for Medical Oncology (ESMO) Virtual Congress 2020.

Phase 3 trial of Tislelizumab + Chemotherapy in First-Line NSCLC:

A total of 334 patients in China were enrolled in the trial, randomized at 2:1 to receive tislelizumab (200 mg every three weeks) in combination with chemotherapy (Arm A) or chemotherapy alone (Arm B).

As of the data cutoff on January 23, 2020, with a median follow-up time of 9.8 months, 97 patients (43.5%) remained on treatment in Arm A and 20 patients (18.0%) in Arm B.

The trial achieved the primary endpoint of progression-free survival (PFS), with a median of 9.7 months in Arm A, a significant improvement compared to 7.6 months in the chemotherapy alone Arm B (p=0.0044; stratified hazard ratio [HR]=0.645 [95% CI: 0.462, 0.902]).

Higher objective response rate (ORR) of 57.4% and disease control rate (DCR) of 89.2% were achieved in Arm A, compared to ORR of 36.9% and DCR of 81.1% in Arm B.

Longer duration of response (DoR) was observed, with a median of 8.5 months (95% CI: 6.80, 10.58) in Arm A, compared to 6.0 months (95% CI: 4.99, not evaluable) in Arm B.

Treatment of tislelizumab in combination with platinum and pemetrexed was generally well-tolerated, with no new safety signals identified.

Phase 2 Trial of Pamiparib in Advanced OC

A total of 113 patients in China with high-grade, non-mucinous, epithelial OC following at least two prior lines of standard chemotherapy were enrolled in the Phase 2 portion of the trial, including 90 patients with advanced platinum-sensitive OC (PSOC) in Cohort 1 and 23 patients with advanced platinum-resistant OC (PROC) in Cohort 2.

The primary endpoint of the study is ORR. As of the data cutoff on February 2, 2020, with a median follow-up time of 12.2 months (0.2, 21.5), results included:

In Cohort 1 of patients with PSOC:

ORR was 64.6%, including eight complete responses (CRs) and 45 partial responses (PRs);

DCR was 95.1%; Cancer antigen (CA)-125 response rate was 79.7%;

The median DoR was 14.5 months (95% CI: 11.1, not evaluable) and the median PFS was 15.2 months (95% CI: 10.35, not evaluable).

In Cohort 2 of patients with PROC:

ORR was 31.6%, including six PRs;

DCR was 94.7%; CA-125 response rate was 38.1%.

Pamiparib was generally tolerated, consistent in patients with PSOC and PROC, and similar to other PARP inhibitors.

https://seekingalpha.com/news/3615236-beigene-presents-promising-tislelizumab-and-pamiparib-data-in-lung-and-ovarian-cancer