Kazia Therapeutics Ltd (ASX:KZA) has released a poster presentation of interim data from the ongoing phase II study of paxalisib (formerly GDC-0084) in glioblastoma, the most common and most aggressive form of primary brain cancer.
The data showing positive overall survival signal was a feature of Kazia's poster presentation during the prestigious American Society of Clinical Oncology (ASCO) annual meeting which was held virtually at the weekend due to the COVID-19 pandemic.
This meeting is one of the premier scientific conferences in the world for research and treatment of cancer and is typically attended by more than 30,000 clinicians, researchers, industry executives, and patient advocates.
Increased overall survival
Analysis of Stage 1 of the study (n=9) shows median overall survival (OS) of 17.7 months, which compares favourably with temozolomide, the existing standard of care, which has a reported median OS of 12.7 months in this patient population
The study also demonstrated a progression-free survival (the ability of a drug to slow the growth of a tumour) in Stage 1 of 8.4 months, which represents a clinically material advantage over the 5.3 months associated with temozolomide.
Kazia chief executive officer Dr James Garner said the company was pleased to be able to share the ‘extremely promising data’ with clinicians in the virtual American Society of Clinical Oncology annual meeting.
He said: “We are pleased to be able to share these extremely promising data with clinicians and partners, albeit in the novel forum of a virtual academic meeting.
“As we have previously said, the gold standard for any new cancer drug is the ability to extend life, and we are seeing evidence from this study that paxalisib may achieve this very challenging goal.
“We expect to begin recruitment to the international GBM AGILE pivotal study in the second half of this year.
“In the meantime, we expect several further data read-outs over the next two quarters.”
Before losing patent protection, the FDA-approved standard of care, temozolomide achieved peak sales in excess of US$1 billion per annum, which provides an indication of the commercial opportunity associated with a new treatment for glioblastoma.
The Kazia study is being conducted in newly diagnosed glioblastoma patients, following surgery and radiotherapy.
Only those patients with an unmethylated MGMT promotor have been recruited.
This genetic marker renders patients effectively resistant to temozolomide and is present in approximately two-thirds of patients.
Thirty patients were enrolled to this study, comprising nine in Stage 1 and 21 in Stage 2.
The company notes that comparison between different studies is always imprecise - but is confident that the magnitude of the numerical difference provides powerful evidence that treatment with paxalisib may extend life in this patient group.
In addition to the paxalisib poster in Abstract 2550 (NCT03522298), abstracts were presented by the Global Coalition for Adaptive Research on the GBM AGILE clinical trial and by the Alliance for Clinical Trials in Oncology on their genomically-guided study in brain metastases, in which paxalisib is one of three participating drug candidates.
The phase II study remains ongoing with approximately half of the total enrolled patient population still receiving drug at the time of analysis and several additional patients still in follow-up.
Kazia expects to complete the study in the first half of 2021.
The lead author on the poster presentation, Dana-Farber Cancer Institute Professor Patrick Wen said: “We anticipate paxalisib will move into a pivotal study later this year and look forward to reviewing further data as it emerges.”
In addition to this phase II study in glioblastoma, four other studies are underway with paxalisib in different forms of brain cancer and it is anticipated that several of these will provide initial efficacy data during 2020.