The question is still open. Apart from having a different mechanism of action, we don't have any data (as far as I am aware) that showed reduction in kidney function decline (eGFR) for Dimerix.
Please note that for Sparsentan FSGS: During the phase II DUET study's 84-week OLE trial, Sparsentan showed strong proteinuria reduction over 84 weeks, but this benefit did not translate into eGFR benefit.
And now for their P3 study, they didn't get the approval not coz they couldn't show proteinuria reduction but because it didn't translate in kidney function improvement measured by eGFR.
I have been saying for few weeks, we should pray for Sparsentan to convince FDA to approve their drug based on Protienuria reduction even though it couldn't show any meaningful clear eGFR benefit in the company's FSGS phase 3. This will significantly de risk us but doubt if FDA will accept this sadly.
For their igAN indication, they were given accelerated approval based on interim results but context is important as below:
On Feb 17, 2023, Travere's (NASDAQ:TVTX) sparsentan received FDA approval for reducing proteinuria in adults with primary IgAN at risk of rapid disease progression. The FDA indication specifically states a urine protein-to- creatinine ratio (UPCR) >=1.5 g/g.
This indication is granted under an accelerated approval pathway based on a reduction in proteinuria, and so far, FDA has noted that it did not show a meaningful reduction in kidney function decline (eGFR).
"It has not been established whether FILSPARI slows kidney function decline in patients with IgAN. The continued approval of FILSPARI may be contingent upon confirmation of a clinical benefit in the ongoing Phase 3 PROTECT Study, which is designed to demonstrate whether FILSPARI slows kidney function decline."
Top-line results from the two-year confirmatory endpoints in the PROTECT Study are expected in the fourth quarter of 2023 and are intended to support traditional approval of Filspari.
Below is from Travere MD, typical response without any data (this is for igAN)
Jula Inrig, M.D., chief medical officer of Travere Therapeutics. “These interim results also strengthen our confidence for a potential longer-term benefit on eGFR, which will be further examined at the completion of the 2-year double-blind period of the PROTECT trial later this year. We are thrilled to share this data with all those working to improve outcomes for people living with rare kidney disease.”IgAN is historically a tougher disease to show eGFR benefits compared to FSGS, and lower doses were use in the IgAN disease vs. FSGS trial.
Its probably worthwhile asking this to Nina as to why we believe we have a case of seeing eGFR reduction when Sparsentas wasn't successful. Do note that there are other drugs approved for igAN that were able to demonstrate eGFR improvement e.g. Tarpeyo. So its not like no one was able to show eGFR improvement.
DXB Price at posting:
7.2¢ Sentiment: None Disclosure: Held
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