Hutchison China MediTech (Chi-Med) has started a Phase I/Ib clinical trial to investigate its small molecule, HMPL-689, for treating patients with advanced relapsed or refractory lymphoma.

HMPL-689 is a selective inhibitor of the isoform phosphoinositide-3 kinase delta (PI3Kδ).

The open-label, two-stage, international Phase I/Ib study will evaluate the safety, tolerability, pharmacokinetics and preliminary efficacy of oral HMPL-689.

The trial, which includes dose-escalation and expansion stages, will enrol around 85 patients at sites in the US and Europe. The first participant was dosed last month in the US.

The dose-escalation part will be concluded when the first three patients dosed at level one will experience three dose-limiting toxicities (DLTs), when the maximum sample size is achieved, or when maximum tolerated dose (MTD) and/or recommended Phase II dose (RP2D) is confirmed.

In the dose-expansion stage, patients with B cell lymphoma will be enrolled to further characterise the safety and analyse the preliminary anti-tumour activity of HMPL-689 at RP2D.

The primary outcome measures of the study are safety and tolerability. The trial will also monitor pharmacokinetic measurements and preliminary efficacy, including objective response rate, as secondary outcomes.

Chi-Med expects to complete the Phase I/Ib trial by April 2023. The company noted that the new study supports a Phase I/Ib dose-escalation and expansion trial of HMPL-689 being conducted in China.

Around 83 lymphoma patients who did not experience an adequate response to standard care or do not have standard of care will be enrolled in the country.

The primary outcome of the trial is the incidence of dose limited toxicities and related HMPL-689 dose, while secondary outcomes are maximum plasma concentration and time to reach maximum concentration.

The study is expected to be completed in 2021.