Tislelizumab Combination Met Primary End Point for First-Line Treatment of Nasopharyngeal Cancer

Tislelizumab plus chemotherapy met its primary end point of progression-free survival (PFS) at the interim analysis of the phase 3 RATIONALE 309 trial (NCT03924986) investigating the combination as first-line treatment for patients with recurrent or metastatic nasopharyngeal cancer, according to a BeiGene, Ltd. press release.¹

The randomized, double-blind, placebo-controlled trial evaluated the safety and efficacy of tislelizumab plus gemcitabine and cisplatin compared with placebo plus gemcitabine and cisplatin for this cohort of patients.

“We are excited to see a clinically meaningful improvement in progression-free survival in our Phase 3 trial for tislelizumab plus chemotherapy in patients with [nasopharyngeal cancer]. This is our fifth positive phase 3 readout for tislelizumab, which we are developing broadly as a potentially differentiated anti–PD-1 antibody,” Yong Ben, MD, Chief Medical Officer, Immuno-Oncology, at BeiGene, said in a press release.

The trial enrolled 263 Asian patients and randomized them 1:1 to receive either tislelizumab or placebo plus chemotherapy. The results showed a statistically significant improvement in PFS for the intention-to-treat (ITT) population treated with tislelizumab plus chemotherapy compared with the placebo plus chemotherapy group. PFS was evaluated by an independent review committee (IRC).

No new safety signals were detected with the anti–PD-1 antibody when chemotherapy was added, as the safety profile was consistent with the previously known risks of the drug.

Secondary end points of the trial including overall survival, objective response rate assessed by IRC, duration of response, and investigator-assessed PFS.

According to the press release, BeiGene expects to present the data at an upcoming medical conference and is also discussing the results with health authorities.

“We are grateful for the patients and clinicians who participated in this trial and hopeful that they may have a new treatment option in the future,” explained Ben.

BeiGene, the biopharmaceutical company responsible for tislelizumab, previously announced preliminary phase 2 data at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting. The research team investigated drug as monotherapy in Chinese patients with nasopharyngeal cancer.²

A total of 20 patients were enrolled in the trial and treated with a dose of tislelizumab at 200 mg every 3 weeks. At the data cut-off point, the median treatment duration was 7.5 months (range, 2.1-15.8 months) with a median follow-up time of 11.7 months.

The most common treatment-related adverse events in this study were hypothyroidism (24%), anemia (14%), increased AST (10%), and hemoptysis (10%).

According to the release, tislelizumab is a “humanized IgG4 anti-PD-1 monoclonal antibody specifically designed to minimize binding to FcγR on macrophages.”

References:

1. BeiGene Announces Positive Topline Results from Phase 3 Trial of Tislelizumab in Combination with Chemotherapy as First-Line Treatment for Recurrent or Metastatic Nasopharyngeal Cancer. News release. BeiGene Ltd. Published May 21, 2021. Accessed May 21, 2021. https://ir.beigene.com/news-releases/news-release-details/beigene-announces-positive-topline-results-phase-3-trial?loc=us

2. BeiGene Announces Preliminary Phase 2 Results of Tislelizumab in Chinese Patients with Nasopharyngeal Cancer at the 2019 ASCO Annual Meeting. News release. BeiGene Ltd. Published June 1, 2019. Accessed May 21, 2021. https://www.globenewswire.com/en/news-release/2019/06/01/1862903/0/en/BeiGene-Announces-Preliminary-Phase-2-Results-of-Tislelizumab-in-Chinese-Patients-with-Nasopharyngeal-Cancer-at-the-2019-ASCO-Annual-Meeting.html