Kazia Therapeutics has reported positive results from a Phase II clinical trial of its therapy, paxalisib, evaluated as a first-line treatment in individuals with glioblastoma, a highly aggressive type of primary brain cancer.
A brain-penetrant inhibitor of the PI3K / Akt / mTOR pathway, paxalisib was licensed by Kazia from Genentech in 2016.
The adaptive, two-stage trial enrolled a total of 30 subjects at six study sites in the US to receive paxalisib as a single agent.
These subjects had recently detected glioblastoma and unmethylated MGMT promotor status, a genetic profile that shows initial resistance to temozolomide.
Temozolomide is the only drug approved by the US Food and Drug Administration (FDA) for first-line therapy.
The first stage of the trial was intended to identify the most suitable dose of the drug for the patients.
Further data on dosing and detection of an initial efficacy signal to commence a larger trial was assessed in the second stage.
The evaluation of the safety and tolerability of paxalisib in trial subjects was the primary objective of the trial.
Pharmacokinetic parameters and efficacy goals such as overall survival (OS) and progression-free survival (PFS) comprised the secondary goals.
Findings showed that 60mg once-a-day dose of paxalisib was found to be the maximum tolerated dose (MTD) and chosen for further trials.
Median OS was found to be 15.7 months, which is comparable to 12.7 months reported with patients receiving temozolomide treatment.
Furthermore, median PFS in subjects treated with paxalisib was 8.4 months, suggesting a significant rise over the comparable figure of 5.3 months with temozolomide.
The OS rose to 15.9 months in the modified intent to treat population, which comprised only individuals who were evaluable for efficacy.
Hyperglycaemia, oral mucositis and skin rash were the most common treatment-associated toxicities reported in the trial with the drug’s safety profile in line with prior trials.
Based on previous interim analyses data, Kazia decided to take part in the global GBM AGILE trial.
This trial enrolled the first subject in the paxalisib group in January this year while recruitment is currently underway.
Kazia Therapeutics CEO Dr James Garner said: “The data continue to demonstrate a clear efficacy signal and favourable safety profile, suggesting a meaningful advantage over temozolomide, the existing standard of care, and validating our decision last year to join the GBM AGILE pivotal study.”
In addition, paxalisib is being analysed in seven trials for primary brain cancer, as well as several cancer types that metastasized to the brain.
The company partnered with the Alliance for Clinical Trials in Oncology Foundation in May 2019 to conduct trials of metastatic brain cancer therapies.