Ibtrozi May Address Unmet Needs In ROS1-Positive Non-Small Cell Lung Cancer

At the 2025 IASLC World Conference on Lung Cancer. CURE sat down with Dr. Geoffrey Liu, a senior scientist at Princess Margaret Cancer Centre and a professor in the Epidemiology Division at Dalla Lana School of Public Health of the University of Toronto, for an interview.

Liu discussed findings from the phase 2 TRUST-II clinical trial evaluating Ibtrozi (taletrectinib) among patients with ROS1-positive non-small cell lung cancer, and shared how this drug may address unmet needs regarding effectiveness and safety among this patient population.

Transcript

Ibtrozi is the drug in question that is being tested in the TRUST-II trial. And one of the things that we have learned is that there are already other drugs that are available and on the market for patients with ROS1 metastatic lung cancer. Unfortunately, these drugs either don't work for long periods of time — they work often between one to three years, if it's the first time they've been using this drug — and at the same time, a number of these drugs will have side effects that will affect patients greatly. They include particularly things such as dizziness, lightheadedness and in some cases, changes in the way they taste food, for instance. So there is a real unmet need for new drugs that have fewer side effects, but also work better and for longer periods than the drugs that are available. So Ibtrozi was really designed for that purpose.

Last year, there was some preliminary data that was reported from the TRUST-II trial, and this year, we're reporting data with a longer length of follow up time. So in other words, we were able to track patients for a longer period of time, on average approximately 20 months, which is five months more than what was reported last year. So the main findings are the following: First of all, the proportion of patients that actually had the tumor shrink when they had never received drug before was 85% and an additional proportion of patients had disease that was stable as well, so that information was actually very useful. On top of it, after 20 months of follow up, the average patient was still basically benefiting from the drug in the sense that neither the duration of response, as well as the progression-free survival, these are two measures of how well someone does and how long they can stay on the drug, the majority of patients were still on on the drug at this time, so that was good.

And then in other population involved patients who received some other drugs before, typically Xalkori (crizotinib) or Rozlytrek (entrectinib). And in those patients, this drug benefited patients on average, about one year or so. But importantly, if you were in the group of patients that did respond to the treatment, you would benefit for more than a year and a half on average. And so that was actually quite important.

But the most important thing, I think, is the fact that, unlike the other drugs that are out on the market, Ibtrozi's safety profile, the side effects that patients will end up receiving from the drug, tends to be much lower in this setting. So there's some laboratory abnormalities that generally don't cause any issues. There are perhaps some issues with nausea, vomiting and diarrhea, but they tend to be very transient and tend to last only a few days, up to a week or so, and very mild in most patients. And the most important thing is that some of the side effects the other drugs had, which often is debilitating dizziness, lightheadedness and changes in the taste, that didn't occur to any great degree with this drug, certainly much less proportion. So both in terms of how effective this drug is and also the side effect profile of this drug, it seems to be better than the other drugs that are commercially on the market right now.

Transcript has been edited for clarity and conciseness.

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