Health Check: Telix licks its wounds after FDA knocks back brain cancer diagnostic

Telix Pharmaceuticals has been shocked by the US Food & Drug Administration’s rejection of marketing approval for its brain cancer diagnostic.

Telix is in the dog house after a shock FDA knock-back, but will regroup and try again. Pic via Getty

• The FDA has told Telix to do more work on its imaging agent for rare brain cancers

• But the agency tells Dimerix it can use a surrogate endpoint for its kidney disease drug candidate

• Emvision opens a second US site to test its stroke detection tool

Telix Pharmaceuticals (ASX:TLX) will seek a ‘please explain’ from the US Food & Drug Administration (FDA) after the agency rejected the company’s marketing approval application for its brain cancer (glioma) diagnostic tool, Pixclara.

The shock news sent Telix shares down as much as 10% this morning.

“This was obviously a disappointing outcome and not what was expected by the company,” said Telix CEO Dr Chris Behrenbruch.

In a so-called complete response letter (CRL), the agency said the entreaty could not be approved without “additional confirmatory clinical evidence”.

Pixclara – TLX101-CDx – is a nuclear imaging agent for glioma, a rare and life-threatening brain cancer.

Currently the FDA has not approved any targeted PET (positive emission tomography) agents for brain cancer imaging. This is despite the technology underlying Pixclara (PET-FET) being used widely elsewhere.

Blindsided

The company is baffled because the FDA reviewers did not raise any concerns in the lengthy consultation process.

The issues appeared to emerge at the late stage, when the parties discussed specific product labelling.

The FDA already had granted orphan drug and fast-track designation to Pixclara, which has been used in early access programs on compassionate grounds.

Choosing his words carefully, Behrenbruch said he believed the decision reflected “a change of culture” at the FDA over the last few months.

“We don’t think it’s a decision that reflects the scientific merit or patient risk benefit of the data,” he told a webinar this morning, adding the parties seemed clear on the data that would be used.

He was not suggesting the FDA had become “less scientifically led”, but there was “less flexibility than we had seen previously towards the back end of the process”.

Behrenbruch says Telix has several options to address the CRL concerns, including re-analysing existing (undisclosed) data, or carrying out additional clinical trials.

Put in context, the FDA has approved two Telix prostate cancer diagnostics. The company is deriving strong revenues from the first, Illucix.

Knock back should not affect kidney application

One issue is the potential impact on the company’s kidney imaging agent Zircaix, which the FDA currently is reviewing.

Behrenbruch said Pixclara was filed under a more flexible and “creative” process called the 505 (b2) pathway.

“The two should not be conflated,” he said.

Given the accepted use of FET-PET elsewhere, the company did not back the Pixclara application with a definitive pivotal trial.

“Zircaix was based on two phase III trials, which far exceeded all their primary and secondary endpoints,” Behrenbruch said.

“We are dealing with a completely different submission process.”

Telix estimates the US glioma opportunity at US$100-$140 million per year. Expanding to additional indications (such as brain metastases) could boost this market to US$475-665 million.

Given Pixclara has not yet been approved, the the knock-back does not affect the company’s current-year revenue guidance.

Still, the episode sounds a warning to FDA applicants that everyone may no longer may be on the same page.

Dimerix can adopt a surrogate

The FDA has delivered Dimerix (ASX:DXB) cheerier news, deeming a so-called surrogate endpoint to be adequate to support potential marketing approval of its drug for a rare kidney disease.

The endpoint is proteinuria – protein in the urine – a tell-tale sign the spuds are not working too well.

A traditional endpoint such as patients’ overall survival is problematic, because complete renal failure and death may not be evident for years.

Dimerix is in phase III trial stage for focal segmental glomerular sclerosis, called Action 3, with an interim analysis showing DMX-200 reduced proteinuria after 35 weeks’ treatment.

Dimerix CEO Dr Nina Webster describes the FDA decree as an “exceptional outcome, particularly given that DMX-200 has previously demonstrated positive effects on this endpoint in both pre-clinical and clinical studies.”

The company says 183 out of 286 intended patients have been dosed in the Action 3 study, with results expected next year.

The FDA also remains “open to discussion” on endpoints that could support accelerated approval.

Pacific Edge fights for pay despite adverse US ruling

Kiwi diagnostics house Pacific Edge (ASX:PEB) says it will continue to fight for restoration of US Medicare reimbursement for its bladder cancer tests, despite a legal setback.

Last week a Pennsylvania District Court judge ruled that her court lacked jurisdiction to hear Pacific Edge’s claim against Novitas – the relevant Medicare contractor – and the Center of Medicare and Medicaid (CMS).

Mind you the beak in question, Judge Keli M. Neary, noted the company had marshalled “incredibly compelling facts for why its test is a medical marvel”.

Pacific Edge’s lobbying efforts have been in vain, despite heavyweight support from the American Urological Association (AUA).

Reimbursement expired on April 24.

The company’s Cxbladder test cover detection and triaging of patients and ongoing monitoring.

Pacific Edge now intends to appeal to the Medicare system, arguing its triage tool is included in AUA clinical guidelines.

It will also pursue coverage for is monitoring tool, but not the detection product as “no new evidence has been published that can be submitted for reconsideration.”

Pacific Edge derives 60% of its US revenue from Medicare – and most of its overall revenue from Trumpland – so it’s no small beer.

Pacific Edge CEO Dr Peter Meintjes says the “flawed process … failed to review the most-current evidence.”

On the bright side, Pacific Edge expects to receive uninterrupted reimbursement from contracted commercial US payers, including US Veterans Administration.

Mayo-my as Emvision opens second trial site

Emvision has added a second US site for its pivotal trial of its portable stroke detection tool, at Mayo Clinic in Jacksonville, Florida.

The company plans a site initiation visit and device training in early May.

The Mayo site augments an existing one at the UTHealth and Memorial Hermann-Texas Medical Center.

The trial aims for FDA clearance of Emu, a point-of-care brain scanner for early detection and classification of strokes.

The company says additional US and Australian trial site will be “announced and activated shortly”.

Percheron board survives – again

The Percheron Therapeutics (ASX:PER) board has survived a second spill attempt following December’s failure of its flagship Duchenne muscular dystrophy (DMD) program.

On Thursday the company said shareholders had voted against removing chairman Dr Charmain Gittleson, CEO James Garner and another director, by a margin of approximately 72-73%.

Curiously, the requisitioning party, Powerhouse Ventures, had halved its stake ahead of the meeting, to just over 5%.

To use a timely political analogy, the board enjoyed a swing in its favour. In March another ginger group failed to eject chairman Gittleson and Garner, by a margin of 55-56% .

“It is now time to put these disputes behind us and focus our entire efforts on the vital task of restoring value for shareholders,” Gittleson says.

With the DMD program dead, buried and cremated, the board plans to use the company’s remaining cash to acquire an alternative program.

At Stockhead, we tell it as it is. While Dimerix and Emvision are Stockhead advertisers, they did not sponsor this piece

Originally published as Health Check: Telix licks its wounds after FDA knocks back brain cancer diagnostic