The Orphan Drug Playbook: The Neuren Story (NEU)

Good morning, Armchair Army,

Welcome to today's edition of The Armchair Analyst, a 5-minute daily update on the ASX life-sciences sector.

What’s the orphan-drug playbook?

Find a rare disease with no approved treatment.

Design a clinical trial that a small biotech can realistically finance.

Work closely with the patient community.

Get the FDA aligned on what success looks like.

Then find a partner willing to pay for the expensive bit.

Print money. Help people.

It seems strange that a drug for a patient population with less than 10,000 people can sell for hundreds of millions of dollars each year.

But that’s an orphan drug.

… and it was the backbone of one of the biggest biotech success stories on the ASX.

From a sub-$50M battler to a $2 billion behemoth.

It set off a cascade of other ASX-listed companies chasing orphan drugs.

… with the market asking.

Please, sir, can I have some more?

(Sorry, I had to get one Oliver Twist reference in there…)

The next company on my Biotech 165 Challenge.

Neuren Pharmaceuticals (ASX: NEU).

But first…

CSL, PME and COH all published their annual reports today.

I’m looking forward to seeing the analyst commentary trickle through today - but here is my quickfire take.

Pro Medicus (ASX: PME) reports revenues of $261.7M (up 22%) and underlying EBIT of $196.1M (up 24.4%). 37c fully franked dividend announced. (PME)

🪑 Some good commentary from the CEO. Everything is looking up for PME.

Cochlear (ASX: COH) reports FY26 sales revenue of $2.343B (down from $2,355B), with underlying Net Profit decreasing to $322M (down 22%). (COH)

🪑 Expenses up. Revenues down. Not a great year for Cochlear.

CSL (ASX: CSL) reports a FY26 net loss of $2.6B due to $7.1B of impairments, while underlying NPATA is $3.1B, with revenue at $15.8B. (CSL)

🪑 The company’s first earnings loss since it listed on the ASX in 1994.

Hopefully it sets the baseline for a strong FY27.

Guidance is set at a 5% increase in underlying profit for FY27.

Vita Life Sciences (ASX: VLS) reports half-year revenue of $48.3M, up 19%, with profit before tax at $8.1M, and declares a 5 cent dividend. (VLS)

Cogstate (ASX: CGS) reports FY26 revenue of $60.9M, up from $53.1M in FY25, with net profit after tax of $11.9M and a significant rise in signed contracts totalling $89M, more than doubling from $41.3M. (CGS)

🪑 Nice result

Adherium (ASX: ADR) secures an additional AUD$1 million short-term unsecured loan from Trudell Medical. (ADR)

🪑 The loan is due in about 45 days. As short-term as it gets.

Developing a drug for a few thousand people sounds like a terrible commercial decision.

Hundreds of millions of dollars on research and development only to sell it to a tiny patient population.

The maths doesn’t make sense.

But what if you could sell that drug for a lot of money?

Like hundreds of thousands of dollars a year per patient.

… and the insurance companies pay for it.

AND the government gives you a bunch of incentives to develop the drug.

Well…

Now it starts to get interesting.

Of course I am talking about orphan drugs.

Treatments for extremely rare diseases that companies develop because the incentive structure around them makes sense.

Show me the incentive, and I’ll show you the behaviour.

But importantly, for our gaggle of ASX-listed biotech companies, orphan drugs provide a meaningful pathway to value that doesn’t require a giant balance sheet.

Aussie companies need to find paths to market that make sense for the amount of risk capital available for late-stage assets.

That is why orphan drugs make sense for ASX-listed companies.

Smaller trials.

Regulatory assistance.

Fee waivers.

Long periods of market exclusivity.

And, in some cases, a voucher you can sell for hundreds of millions of dollars.

The patient population remains tiny.

But the commercial opportunity isn’t.

It is a pathway that small-cap ASX-listed companies can afford to walk AND make big money from.

It’s no surprise that several of our late-stage biotech companies have gone down this path.

Mesoblast.

Alterity.

Dimerix.

And one company that became the blueprint…

The original ASX orphan-drug success story.

The next company in my Biotech 165 Challenge.

Neuren Pharmaceuticals (ASX: NEU).

Neuren has been listed on the ASX for over 20 years.

Its first attempt at bringing a drug to market was for brain injury… Phase 3 showed no treatment effect.

(Results on Christmas Eve in 2008, no less)

The follow-up compound, NNZ-2566, later called trofinetide, then moved into traumatic brain injury.

That failed in the Phase 2 trial around 2016.

But one clinical trial was running in the background and offered some hope.

The “side bet” was a little-known disease called Rett Syndrome.

Rett syndrome is an incredibly rare genetic neurodevelopmental disorder.

There are around 6,000 to 9,000 patients in the United States.

… almost all young girls.

This was the target Neuren decided to pursue.

An orphan drug.

… and it built a $2B business from it.

Orphan Drugs Explained

It’s hard to tell the story of Neuren without talking about orphan drugs first.

Orphan drugs are drugs that are used to treat rare diseases that affect a small number of people.

The term “orphan” dates back to 1963, when Birmingham paediatrician Dr Harry Shirkey called children “therapeutic orphans” because companies were not testing medicines for them.

At the time, money flowed to diseases with large patient groups.

(Big fish like cancer and heart disease)

Which meant that families with children with rare diseases often had no hope.

Therapeutic orphans.

To encourage companies to develop treatments for rare diseases, President Reagan signed the Orphan Drug Act on 4 January 1983.

These are the benefits that orphan drugs can afford:

Orphan drugs also command orphan drug pricing.

Orphan drugs typically sell for around US$200,000 per patient per year.

(For ultra-rare conditions, they can fetch up to US$3M per patient per year).

Insurance companies and government health programs - the ones that pay these costs - can justify it on the basis of paying risk-pooling economics and long-term cost avoidance.

The concept of risk pooling is interesting. 

If an insurance pool has 2 million members, and one member requires a $500,000 orphan drug, that cost translates to just $0.25 per member per year. 

The premiums of the healthy majority easily absorb the high cost for the one sick member.

Neuren’s treatment starts at US$385,000 per year per patient and increases based on the patient's weight.

So this was the path that Neuren took.

The orphan road.

Positive Phase 2 results in March 2017.

18 months later, it had secured a licencing deal to finance the entire pathway to commercialisation.

… and the market hated it.

On 6 August 2018, Neuren licensed North American trofinetide rights to Acadia Pharmaceuticals (NASDAQ: ACAD).

Neuren received US$10 million upfront and up to US$455 million in development and sales milestones,

Escalating double-digit royalties and one-third of any voucher proceeds.

(Which ended up selling for US$150M)

Acadia also agreed to fund and run the Phase 3 trial, the FDA filing and the commercial launch.

The market hated it.

Neuren’s stock fell 43%.

From A$2.67 to A$1.52 the next day, before sliding to A$1.04 by the end of August.

Investors thought the upfront and royalty were too small, and Acadia wasn't the partner they wanted.

I think the market missed the key point that Acadia paid for the entire Phase 3 clinical trial, as well as the FDA filing.

These are key costs for any ASX-listed company.

Looking at some Phase 3 (or Phase 3-ready) companies on the ASX today, they’ve had to find creative ways to finance the trial.

You never want to go into a clinical trial without fully financing it.

But ASX-listed companies don't always have that luxury.

Take a look at Paradigm. 

They financed their Phase 3 clinical trial through a convertible note with Obsidian (which has put downward pressure on the share price every time it converts).

Take a look at Dimerix.

Before the interim results for its Phase 3 clinical trial in 2023, it ran out of cash and needed an emergency capital raise with a 2-for-2 option.

Getting someone else to drag you across the finish line is a luxury.

Especially in small-cap ASX land.

So while Neuren gave up much of the upside potential, they took out a big portion of the risk.

Now Neuren gets a nice royalty stream and has the capital flywheel to self-fund the next programs.

Neuren and its partner Acadia got two key parts of running the trial for an orphan disease right.

FIRST, it integrated very closely with the Rett Syndrome community.

This helped with patient recruitment, trial design and ultimately commercialisation (Neuren knew all of its potential customers).

SECOND, it secured FDA agreement on the endpoints it wanted.

Endpoints = the “win condition” for the trial.

Acadia proposed the Rett Syndrome Behaviour Questionnaire (RSBQ) as the primary endpoint.

The FDA wanted a second measure showing that any change was clinically meaningful.

So the clinician-rated CGI-I became the co-primary endpoint.

Because Neuren worked so closely with the Rett Syndrome community, it brought in clinicians who work directly with patients to the FDA meetings to discuss which endpoints would matter to them.

This worked..

On 6 December 2021, Neuren announced that its drug trofinetide had met both co-primary endpoints in the 187-patient Phase 3 trial.

The Rett Syndrome Behaviour Questionnaire (RSBQ) score improved by 5.1 points for patients taking trofinetide, compared with 1.7 points on placebo (p=0.0175).

The clinician-rated CGI-I score also favoured trofinetide (p=0.0030).

The effects were modest.

But they were real.

When you are treating a rare disease with no approved options, the regulator can consider the totality of the evidence, the seriousness of the condition and the enormous unmet need.

A modest improvement can still matter when the alternative is nothing.

On 10 March 2023, the FDA approved trofinetide under the brand name DAYBUE, making it the first treatment approved specifically for Rett syndrome.

DAYBUE is an oral treatment taken twice daily, once in the morning and once in the evening.

It was originally launched as a strawberry-flavoured liquid, with the dose based on the patient’s weight.

Neuren’s partner Acadia has since added DAYBUE STIX, a powder formulation designed to make taking and transporting the drug a little easier.

Since the US launch in April 2023, Neuren has received approximately A$525 million from Acadia.

That includes upfront payments, milestone payments, royalties and Neuren’s share of the Priority Review Voucher sale.

For 2026, Neuren is guiding to US$53–56 million in DAYBUE royalties, after Acadia increased its full-year sales guidance to US$480–510 million.

(Largely off the back of the successful launch of the DAYBUE STIX formulation)

Neuren is effectively a royalty-printing machine.

Its partner, Acadia, runs the commercial engine.

Manufacturing.

Marketing.

Reimbursement.

Sales.

Neuren receives a percentage every time Acadia sells the drug.

Cash coming through the door based on sales made by someone else.

Taking lessons from how Acadia ran the clinical trial for Rett Syndrome, Neuren is using some of the capital to finance its next trial.

Phelan-McDermid syndrome.

Another rare disease associated with intellectual disability, absent or badly delayed speech and autism-like features.

The open-label Phase 2 was reported on 18 December 2023.

Ten of 14 efficacy endpoints were statistically significant, and 16 of 18 children improved on the clinician impression scale.

The Koala Phase 3 plans to enrol about 160 children aged 3 to 12 for thirteen weeks in a randomised, double-blind, placebo-controlled study, using co-primary endpoints agreed face-to-face with the FDA.

The first patient was dosed on 6 February 2026, and the trial has also been approved to expand into Canada.

Unlike the Rett Syndrome trial, Neuren is going into this one owning 100% of the asset.

The closer that it gets to a readout, the more value it can secure in licencing and commercial deals.

(and potentially be a takeover target itself one day)

Neuren, the royalty-printing company, isn't that interesting as a takeover target.

Neuren, the royalty-printing company with another late-stage orphan drug…

That’s interesting to big pharma.

Behind Koala, Pitt-Hopkins had positive Phase 2 data in May 2024 but is still working through its next design with the FDA, while Angelman had positive Phase 2 data in August 2024 but no announced Phase 3.

Phelan-McDermid, Pitt-Hopkins and Angelman all have Fast Track designation, with orphan and rare paediatric disease designations across the programs.

Neuren has nearly A$300 million in the bank.

More than enough to fund the upcoming clinical trials without going back to shareholders.

I remember listening to Jon Pilcher speak at the Monsoon event earlier this year in February, and the company was talking about a share buyback.

For context…

A week earlier, the CHMP (European regulator) delivered its negative opinion on DAYBUE, sending Neuren’s share price back towards A$11.

THEN, a few months later, the CHMP reversed its decision.

Europe was back in play.

Now the stock trades at $23.

Personally, I have never loved buybacks.

They can feel like something companies do when they have run out of ideas.

But Neuren’s buyback was different.

The company genuinely believed its shares were undervalued at $11.

(Which they were at the time)

Lesson for me = pay attention when companies announce buybacks.

The company paused the buyback in May while it reconsidered its capital-management strategy.

My read?

The stock had recovered to $23… The buyback was no longer needed.

Which brings us to option two…

Dividends.

Neuren has never paid one.

But I had an interesting chat with Jon about this at the Bioshares Summit, and it is something the company has to seriously consider.

Australia’s 50% CGT discount will be replaced by cost-base indexation and a minimum 30% tax rate on capital gains accruing from 1 July 2027.

That could change how Australian investors think about growth assets compared with income-producing assets.

Neuren will always be positioned as a growth stock.

But…

A growth stock paying a franked dividend?

That could command a premium in a market where the tax treatment of capital gains is becoming less attractive, and income matters more.

(I think we are already starting to see this in the growing popularity of yield-focused ETFs.)

Then there is option three…

Buy something.

Neuren has cash.

Regulatory experience.

Rare paediatric neurology expertise.

And a management team that has already taken one drug from the clinic to FDA approval.

Meanwhile, plenty of small rare-disease companies have a promising asset and around 18 months of cash.

For once, Neuren is sitting on the other side of that table.

We have seen something similar in medical imaging.

Pro Medicus provided A$10 million of strategic capital to 4DMedical (ASX: 4DX) in 2025 through a hybrid debt-and-equity structure.

The stock 10-bagged.

It then signed a binding heads of agreement with Echo IQ (ASX: EIQ), establishing the framework for a proposed investment of up to A$20 million and a proposed US reseller relationship.

Days later, EIQ raised approximately A$110 million through an institutional placement.

Those were not random sharemarket punts.

Pro Medicus used its capital, customer network and industry experience to back technologies that could eventually strengthen its own platform.

While making investments that grew significantly in value too.

It had the midus touch.

Neuren could do something similar in rare disease.

Take strategic positions in smaller ASX-listed companies.

Help fund orphan-drug programs.

And use its regulatory experience to help those programs move through the clinic.

In my eyes, this is probably the least likely option.

Neuren has not built its reputation by spraying money around.

BUT…

If the right asset came along…

An acquisition, or even a strategic investment, could turn Neuren from a DAYBUE royalty stock into a genuine rare-disease franchise.

Neuren has written the playbook for other ASX-listed drug developers to follow.

The orphan drug playbook.

While it gave up quite a bit of the upside on the deal to Acadia…

In hindsight, it was a very good deal.

Not many companies get a “free roll” at a Phase 3 clinical trial.

AND a partner who is dedicated to commercialising the drug.

Sometimes the step below big pharma works best.

A drug can get lost in the shuffle of a big business, but for Acadia, DAYBUE is their flagship product.

That means all their attention is on getting it to as many patients as possible.

Neuren gets to enjoy Acadia's relentless attention and execution on DAYBUE.

… but now it can take all the lessons it learned watching Acadia and apply them to its own trial in Phelan-McDermid syndrome.

Neuren is in a luxury position for any ASX-listed biotech.

It has cash.

But it's also thinking about what comes next.

How to build a truly valuable pioneer in the industry.

I love the Neuren story because it gives hope to all ASX-listed drug developers out there that even though we fight scrappy… we can win.

An underdog story, and a true victory for the small-cap biotech industry.

A big thank you to CEO Jon Pilcher for sharing the Neuren story with me.

See you all tomorrow,

The Armchair Analyst.