Biotech Values

[DewDiligence]

Re: Duration info in Daxi’s FDA label

Daxi’s duration data is likely to reside in the Clinical Studies section of the label rather than the Indications and Usage section at the top. While the Clinical Studies section is less prominent, I don’t think this distinction matters much in the overall scheme of things.

The duration data will almost certainly be presented via one or more Kaplan-Meyer curves derived from RVNC’s SAKURA phase-3 studies. The Clinical Studies section of the label may contain K-M curves showing: 2-point change from baseline; 1-point change from baseline; time retaining “none or mild” status (which is sort of a “1.5-point” metric*); or time to return to baseline, which is a variant on the “none or mild” metric that produces slightly longer readings (because the time is extended to the first observation after return to baseline).

The salient point in all this is that Daxi’s duration of effect is not a single number, but rather a range derived from the K-M curves. The narrative in the label may cite such a range; if so, “approximately 4-6 months” would be sufficient to establish Daxi’s differentiation from all other approved botulinum toxins; anything better than that would be icing on the cake.

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*Retaining “none or mild” status represents a 2-point change from baseline for: a) patients who started with moderate wrinkles and have no wrinkles at the measured time point; and b) patients who started with severe wrinkles and have mild wrinkles at the measured time point. On the other hand, retaining “none or mild” status represents a 1-point change from baseline for patients who started with moderate wrinkles and have mild wrinkles at the measured time point.