Telix Pharmaceuticals has pointed to “promising efficacy” for its radiation therapy in a small, single arm study of patients with brain cancer.
The phase 2 Ipax-Linz trial enrolled eight patients with recurrent high-grade glioma, who received adaptive intravenous dosing of TLX101, a radiation therapy that targets L-type amino acid transporter (LAT1), along with external beam radiation therapy (EBRT). The primary endpoint of the study was safety and tolerability, and Telix said the treatment was “well tolerated with no serious adverse events reported.”
When it came to the study’s secondary endpoints of survival, Telix pointed to a median overall survival (OS) rate of 12.4 months from the initiation of TLX101 treatment, or 32.2 months from initial diagnosis.
The Australian biotech said this was consistent with the median OS of 13 months from TLX101 treatment in the Ipax-1 study last year of patients who were being treated after the first recurrence of glioma following standard radiochemotherapy. The Ipax-Linz trial reported yesterday included patients treated after either their first or second recurrence.
Telix also compared these OS rates seen with TLX101 to historic median survival of 9.9 months among patients with recurrent glioblastoma who receive EBRT only.
Telix’s chief medical officer David Cade said the “encouraging results offer new options for patients with historically poor outcomes.”
Josef Pichler, Ph.D., of Kepler University Hospital in Austria, who was the study’s principal investigator in both the Ipax-Linz and Ipax-1 studies, said the latest preliminary results “showed that TLX101 treatment was very well tolerated, with no serious adverse events, at a higher dose than in previous studies.”
Despite five of the eight patients having MGMT unmethylated tumors, which can have especially poor outcomes, Pichler said the Ipax-Linz trial had corroborated the efficacy seen in IPAX-1.
Glioblastoma has a poor prognosis with treatments typically limited to surgery, radiotherapy and chemotherapy (namely temozolomide), though the disease tends to return after treatment, with the five-year survival rate estimated at just 5% to 10%. Roche's Avastin has for many years been FDA-approved for this type of brain cancer, but follow-up treatments for this difficult-to-treat tumor have been lacking.
“These results also potentially support higher therapeutic doses” Pichler added, as the company will now need to focus on the next stage of testing that will involve “controlled studies,” as it seeks to prove the treatment's efficacy outside of a single-arm study with a focus on safety in the hope of a future regulatory admission.
William Blair analysts noted the small size of the trial, but said they were still “intrigued” by the survival data.
In an April 16 note, the analysts highlighted that TLX101 is “amenable to be combined with external beam radiation,” as well as that the candidate “appears to be active in recurrent glioblastoma patients regardless of methylation status.”
Telix had at one point last year been lining up a $200 million Nasdaq IPO but had second thoughts at the last minute. Instead, the company channeled its energies into fleshing out its radiopharma capabilities, including the $13.6 million acquisition of Texas-based CDMO IsoTherapeutics, the $82 million purchase of ARTMS and its cyclotron-based isotope production platform, the acquisition of RLS Radiopharmacies to secure access to RLS’ network of 31 radiopharmacies across the U.S. and buying assets from radiopharma ImaginAb.