Kazia's Paxalisib Shows Positive Overall Survival Signal in Phase II Glioblastoma Study

Kazia Therapeutics Limited (ASX: KZA; NASDAQ: KZIA), an Australian oncology-focused biotechnology company, is pleased to share positive interim data from its ongoing phase II study of paxalisib (formerly GDC-0084) in glioblastoma, the most common and most aggressive form of primary brain cancer.

Key Points

• Interim analysis of Part A (escalation cohort) (n=9) showed median overall survival (OS) of 17.7 months, representing a clinically meaningful extension of life when compared to the 12.7 months associated with the existing standard of care, temozolomide
• Interim analysis of all evaluable patients (Part A = 9; Part B = 21) shows median progression-free survival (PFS) of 8.5 months, broadly in line with previous analysis, and comparing favourably to the 5.3 months associated with temozolomide
• The longest-treated patient remains progression-free 19 months after diagnosis
• Approximately half the enrolled patients remain on drug and both OS and PFS figures may further improve as the trial progresses toward conclusion
• Kazia expects to present further data in 2H CY2020 and final data in 1H CY2021

Summary of Paxalisib Data in Comparison to Temozolomide (existing standard of care)

Kazia CEO, Dr James Garner, commented, "This is an excellent result, and we are delighted with the emerging data. The 'gold standard' for any new cancer treatment is the ability to extend life - an especially challenging goal in a disease such as glioblastoma - and this data provides our first evidence that paxalisib may achieve this objective in a very challenging patient population."

He continued, "There have not been any new drug treatments for newly-diagnosed glioblastoma patients for over twenty years, and we aspire to change that situation. We believe that paxalisib is rapidly becoming one of the most promising drug candidates in the global pipeline for this very challenging disease and we will be working strenuously to make it available to patients as quickly and efficiently as possible. The study continues to follow a number of patients who remain on treatment, and we currently expect to report a further data read-out in the second half of the year."

Background

The reported overall survival (OS) figure of 17.7 months represents a strong signal of clinical efficacy. The existing, FDA-approved standard of care, temozolomide, is associated with an OS of 12.7 months in this patient population^[1]. Comparison between different studies is always imprecise, but the magnitude of the numerical difference provides powerful evidence that treatment with paxalisib may extend life in this patient group.

The reported progression-free survival (PFS) figure of 8.5 months is slightly better than the figure of 8.4 months previously reported in November 2019. Temozolomide is associated with a PFS of 5.3 months in this patient population.

Before losing patent protection, 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.

Thirty patients were enrolled to this study, comprising 9 in Part A, and 21 in Part B. Data reported here are provisional figures from Part A (for OS) and from the entire study population (for PFS), but may change as ongoing patients proceed through the study. The study has been conducted at leading centers of excellence in the United States.

The safety of paxalisib remained broadly consistent with prior experience, with hyperglycaemia (raised blood sugar), oral mucositis (mouth ulcers), and low-grade rash among the most common drug-related toxicities.

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 CY 2020.

This data had been accepted for presentation at the annual meeting of the American Association of Cancer Research (AACR) in San Diego, CA from 24 -29 April 2020. However, given the cancellation of the AACR meeting due to the COVID-19 outbreak, Kazia has determined to provide an update to investors via this ASX announcement.

Next Steps

The phase II study remains ongoing, with approximately half of the total enrolled patient population still receiving drug at the time of analysis and a number of additional patients still in follow-up. At this stage, Kazia expects to present further data in 2H CY2020, and final data in 1H CY2021.

[ENDS]

About Kazia Therapeutics Limited

Kazia Therapeutics Limited (ASX: KZA, NASDAQ: KZIA) is an innovative oncology-focused biotechnology company, based in Sydney, Australia. Our pipeline includes two clinical-stage drug development candidates, and we are working to develop therapies across a range of oncology indications.

Our lead program is paxalisib (formerly GDC-0084), a small molecule inhibitor of the PI3K / AKT / mTOR pathway, which is being developed to treat glioblastoma multiforme, the most common and most aggressive form of primary brain cancer in adults. Licensed from Genentech in late 2016, paxalisib entered a phase II clinical trial in 2018. Interim data was reported in April 2020, and further data is expected in 2H 2020. Paxalisib was granted orphan designation for glioblastoma by the US FDA in February 2018.

TRX-E-002-1 (Cantrixil), is a third-generation benzopyran molecule with activity against cancer stem cells and is being developed to treat ovarian cancer. TRX-E-002-1 is currently undergoing a phase I clinical trial in Australia and the United States. Interim data was presented at the ESMO Congress in September 2019, and the study remains ongoing. Cantrixil was granted orphan designation for ovarian cancer by the US FDA in April 2015.

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