Mondego Bio Begins First Human Study of Cancer Drug MB‑388

Phase 1a study will test safety and drug activity

The randomized, double-blind, placebo-controlled Phase 1a study will evaluate single and multiple ascending doses of MB‑388 in healthy volunteers. Mondego Bio said the trial will assess safety and tolerability, characterize pharmacokinetics, or PK, and measure target engagement through blood-based pharmacodynamic, or PD, biomarkers.

The study is intended to show how exposure to MB‑388 relates to pathway engagement and tolerability. Initial human PK and PD data are expected in December 2026.

“Starting the first clinical study of MB‑388 is an important milestone for Mondego,” Nikolay Savchuk, chief executive officer of Mondego Bio, said. He added that the Phase 1a study will provide data to support moving into the company’s planned study in patients with cancer.

Drug is designed for use with checkpoint inhibitors

MB‑388 was designed to act in both tumor cells and immune cells. Mondego Bio says the program is intended to overcome a central limitation of this inhibitor class, achieving sustained target coverage with an oral molecule while preserving a therapeutic window broad enough for combination with checkpoint inhibitors.

In head-to-head preclinical studies against osunprotafib, which Mondego describes as the leading clinical-stage PTPN2/PTPN1 inhibitor, MB‑388 showed a substantially higher unbound fraction in human plasma, higher oral exposure and longer target coverage. The company also reported more than 1,000-fold selectivity over unrelated targets and favorable exposure margins in rodent and non-rodent safety studies.

In preclinical tumor models that either responded to or resisted PD‑1 blockade, MB‑388 was active as monotherapy and in combination with anti-PD‑1 treatment. Treatment increased intratumoral CD8-positive T cells and granzyme B, findings that Mondego said were consistent with the intended immune-mediated mechanism.

Patient trial planned for January 2027

Mondego Bio plans to begin a Phase 1b study in January 2027 for patients with advanced solid tumors who have progressed on or after standard therapy. The study will include patients previously treated with checkpoint inhibitors.

The trial will first evaluate MB‑388 as monotherapy. After initial monotherapy dose levels have been cleared, the company plans to add a combination run-in with PD‑(L)1 blockade. The combination program will include both checkpoint-refractory and checkpoint-naive patients.

A readout from combination dose escalation is planned for December 2027. The planned studies will provide the first clinical tests of whether MB‑388’s preclinical activity and intended pathway effects translate to people, although Mondego Bio cautioned that its statements about study design, timing, results and therapeutic potential are forward-looking and subject to risks and uncertainties.