Dimerix (ASX:DXB) gets ready for game day

Our sister company Pitt Street Research published a research update on the Melbourne-based drug developer Dimerix (ASX: DXB). Pitt Street Research used to have a valuation range of between 84 cents to $1.07 per share on Dimerix, but with this latest research the new range is $1.65 to $2.17. That’s considerably higher than the 28 November close of 52.5 cents.

Dimerix is in Phase 3 clinical development with DMX-200, for an Orphan kidney disease called Focal Segmental Glomerulosclerosis (FSGS) . If Dimerix gains approval for the drug its brand name will be Qytovra. You may never have heard of FSGS but if Qytovra has the goods in term of improving treatment outcomes there’s probably a $3bn market opportunity. The reason to pay attention to Dimerix right now is the potential for this product to suddenly enter what we call the ‘fast line’.

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Life in the fast line

What do we mean by the fast lane? Well, for one thing, this Phase 3 study, called ‘ACTION3’, is the only one which regulators in the US and the EU have required for Qytovra. Ordinarily two Phase 3s are needed before a drug can gain approval. For another, the endpoints required in ACTION3 have changed in the last year or so, and that might speed up the process of getting Qytovra on the market because the study is nearing one of those endpoints now.

The investigators in ACTION3 have been tracking Qytovra’s performance in two ways. One is ‘proteinuria’ and the other is ‘estimated Glomerular Flow Rate’, or eGFR for short. The kidney is a bean-shaped organ that acts as the body’s filter, removing waste products from the blood and producing urine. When it starts to malfunction, it tends to allow more and more protein to slip into the urine, which is proteinuria, while the rate at which the glomeruli in the kidneys can filter blood each minute -the eGFR – starts to fall. When we start life our kidney’s eGFR is about 120. When kidney failure is getting ready to kill you, you it’s only about 15.

Stage 2 action

In ACTION3 the patients recruited take either 120 mg twice daily of Qytovra or placebo. The study has three stages. Stage 1, which evaluated the first 72 patients at the 35 week mark, was passed in March 2024. Here the investigators were tracking for reduction in proteinuria. An Independent Data Safety Monitoring Board analysed the data and found that Qytovra was, at that time, performing better than placebo in reducing proteinuria, with statistical significance. The data remained blinded to Dimerix.

We’re now in Stage 2, and this is where the ACTION3 story gets interesting. Stage 2 was planned to evaluate the first 144 patients mid-way through the trial for reduction in both proteinuria and eGFR. Dimerix has previously flagged that a statistically significant reduction in proteinuria for the treated patients could potentially allow the FDA to grant accelerated approval. This point was originally planned at 35 weeks, however it’s now at 52 weeks because the FDA subsequently changed its guidance, in a good way. ACTION3’s Stage 3, which concludes the study, will evaluate approximately 286 patients at the 104 week mark for reduction in both proteinuria and eGFR. Dimerix believes it can recruit all 286 patients in the second half of calendar year 2025, so 104-week treatment of the last patient will potentially be reached in late 2027.

Opening the parasol

The reason Stage 2 of ACTION3 is important is because of the ‘PARASOL Initiative’. In May 2023 another FSGS drug candidate called Sparsentan, from Travere Therapeutics (Nasdaq: TVTX), failed at Phase 3 because the drug did not achieve its primary efficacy eGFR endpoint. The PARASOL Initiative was where all the available FSGS data from all the players was pooled, with FDA encouragement, into one big data set. The idea was to evaluate if proteinuria could be validated as an alternative surrogate endpoint for full approval based on changes from baseline proteinuria. This led, in April 2025, to the FDA’s official acceptance of proteinuria as a surrogate endpoint for Qytovra in FSGS.

That changed the game for Dimerix. Before, it had to reach the end of Stage 2 and show efficacy on eGFR. Now, it can potentially show efficacy on proteinuria, albeit at 52 weeks rather than 35, and get the same accelerated approval. That’s encouraging because, when the PARASOL dataset was analysed based on a Dimerix patient population, the result was a correlation in preserving kidney function following reductions in proteinuria over both a 52 and 104 week measurement period. This was announced in October of this year.

A new endpoint

Dimerix has now requested a meeting with the FDA to obtain further guidance on which endpoint would be required for both 52 weeks and 104 weeks. Dimerix has advised that the meeting will happen before the end of calendar 2025. Potentially the FDA could require proteinuria on a 52 week endpoint and eGFR on 104 weeks. Whatever the Agency tells Dimerix in that meeting, the ACTION3 Independent Data Safety Monitoring Board will then look at baseline variability to see if the study has been adequately powered for the selected endpoint.

Now, that may mean more patients are required than the original 286 for proper powering. However, once Dimerix is satisfied that it has adequately powered the study, and the FDA is aligned, it can then proceed to unblind. This can potentially happen early in calendar 2026. That’s right, folks…we are potentially only weeks away from finding out if Qytovra passed the all-important Stage 2. And if the preferred endpoints have been achieved at the 52 week mark, Dimerix can then proceed to file for FDA approval of Qytovra.

The next Neuren?

Now, Dimerix doesn’t have an approved drug right then. The filing has to be accepted by the FDA and then evaluated. However, there could potentially be a PDUFA data in late 2026 or early 2027. A PDUFA data is the data which the Agency has committed to say yes or no to a New Drug Application. So, it could be that Dimerix is only about a year out from having a drug approved in the US.

That other drug we mentioned above, called Sparsentan, now has a PDUFA date of 13 January 2026, with Travere having filed a supplemental New Drug Application for approval of sparsentan based on proteinuria earlier this year. So Qytovra may not get the FSGS field completely to itself. However, approval for Sparsentan next month is arguably good for Dimerix even if Qytovra is later in coming. For one thing, Qytovra and Sparsentan are different products targeting a different treatment pathway. For another, FDA approval of Sparsentan will mean further acceptance of proteinuria as an approvable endpoint. An approval will also support market growth, with physicians diagnosing more patients and differentiating between the different kidney diseases.

It’s not often that an Australian-based drug developer gets this far, but when it does the results can be significant from a share price perspective. Just check out Neuren Pharmaceuticals (ASX: NEU) in 2023 and 2024 when the stock went from under $4.00 to close to $25.00. For more on this opportunity, check out the report from Pitt Street Research.

Disclosure: Pitt Street Research director(s) own shares in Dimerix.