BeOne Medicines’ Combo Cancer Trial Reaches Completion: What Investors Should Watch Next

BeOne Medicines (ONC) announced an update on their ongoing clinical study.

BeOne Medicines’ latest clinical update centers on a Phase 1b study titled “A Phase 1b, Open-Label, Dose-escalation and Expansion Study to Investigate the Safety, Pharmacokinetics and Antitumor Activities of a RAF Dimer Inhibitor BGB-283 in Combination With MEK Inhibitor PD-0325901 in Patients With Advanced or Refractory Solid Tumors.” The study aims to find a safe and active dose of the drug pair in adults with advanced solid tumors that no longer respond to standard care, a key early step before any larger, late-stage trials that could support broader commercial use.

The trial tests two oral cancer drugs in combination: lifirafenib, a RAF dimer inhibitor, and mirdametinib, a MEK inhibitor. Both are designed to block related signals that help tumors grow, with the goal of producing stronger and more durable responses than either medicine alone in patients whose cancers carry specific mutations.

This is an interventional Phase 1 study with no placebo group. Doses are assigned in a non-random way, starting at low levels and moving higher to find the best tolerated schedule (Part A), then moving to an expansion phase in a defined patient group (Part B). The trial is open-label, meaning both doctors and patients know what is given, and its main purpose is treatment-focused: to assess safety first while looking for early signs that the drug combination can shrink or control tumors.

The study was first submitted in April 2019, marking the formal start of the clinical plan. It has since reached overall completion, indicating treatment and follow-up are done and data are being analyzed. The primary completion date (not specified here) would have been the point when main safety and early activity data were collected, while the most recent update on January 6, 2026, shows that the record has been refreshed, often a signal that new analyses, follow-up information, or reporting steps are underway.

For investors, this completed early-stage study helps define the risk and opportunity around the lifirafenib–mirdametinib combination. Positive safety and activity data could support partnering, out-licensing, or progression into larger trials, which may lift sentiment toward companies tied to the program and, by extension, influence views on peers developing targeted therapies in the same pathway. At the same time, competition in targeted oncology is intense, and many large players already market or develop similar pathway inhibitors, so any upside will depend on whether this combo shows clear benefits over existing or emerging options in hard-to-treat solid tumors.

This study is now completed and recently updated, with further details available on the ClinicalTrials portal.

To learn more about ONC’s potential, visit the BeOne Medicines drug pipeline page.