Turning Point Therapeutics has posted early phase 2 data on ALK inhibitor repotrectinib that suggest it may pose a threat to Roche’s Rozlytrek. Buoyed by the data, Turning Point is tweaking the trial with a view to pulling forward a filing for FDA approval.
Repotrectinib is one of several molecules designed to treat cancers driven by ROS1-fusion mutations. Patients with ROS1 rearrangements, which are found in 1% to 2% of people with non-small cell lung cancer (NSCLC), are already served by Pfizer’s Xalkori and Roche’s Rozlytrek. Yet, Turning Point has spied an opportunity to muscle into the field and persuaded investors it has a shot at doing so.
The interim update from a phase 2 trial provides an early look at whether Turning Point can pull off that plan. Six of the seven ROS1-positive, TKI-naïve NSCLC patients treated with repotrectinib responded to the drug, resulting in an objective response rate (ORR) of 86%.
While the number of patients is small, meaning the ORR could change as the trial expands, the data so far suggest repotrectinib is a legitimate challenger. Roche won FDA approval for Rozlytrek in NSCLC on the strength of a 51-subject trial that linked the drug to a 78% ORR.
Turning Point’s data drop also contains evidence that there could still be a market for repotrectinib if it fails to supplant its rivals as the preferred first-line option. The ORR in pretreated patients ranged from 40% to 67%, depending on what medicines they had previously taken.
On the safety front, more than 60% of patients experienced dizziness. Most cases were grade 1, with just a few grade 2, and none led to treatment discontinuation. No patients experienced grade 4 or 5 adverse events of any kind.
Turning Point shared the data alongside an update on its discussions with the FDA. Based on its talks with the agency, Turning Point thinks it may be possible to truncate its path to market by using data on phase 1 patients who received the recommended dose of repotrectinib and by making changes to the cohort sample sizes.
“We are modifying the TRIDENT-1 study sample sizes and adding new interim analyses that may support approval into two of our ROS1-positive TKI-pretreated patient cohorts. We now anticipate providing an update in early 2021 on the overall study timelines,” Turning Point CEO Athena Countouriotis said in a statement.