VRTX VERA Otsuka eGFR possibly suggesting BAFF/APRIL is better, or simply sibeprenlimab worse

Research evidence excerpt

VRTX VERA Otsuka eGFR possibly suggesting BAFF/APRIL is better, or simply sibeprenlimab worse

Biotechnology - Immunology

Genetic Medicines - Market Weight

Immunology - Market Overweight

VRTX VERA Otsuka eGFR possibly suggesting BAFF/ June 5, 2026

APRIL is better, or simply sibeprenlimab worse

The Wolfe Byte

Otsuka showed inferior eGFR data to atacicept, but VERA continues to trade weakly. This magnifies the importance

of successful eGFR data (3Q) for VERA to remove bearish narratives, but investors may be more likely to assign

the value to VRTX.

News Otsuka showed mean eGFR slope with sibeprenlimab at -3.0 mL/min/year (48 week phase 3 analysis). Side-by-

side vs mean eGFR slope with atacicept at -0.6 (96 week Origin 2b analysis). According to large longitudinal studies,

an eGFR decline rate of around -1.0 is considered healthy (more negative is worse; link)

Fundamentally, we view this as a positive for both Vera & Vertex, and more importantly it amplifies Vera's

advantage heading toward full approval (report). For Otsuka's next readout in the summer, rough math suggests that

sibeprenlimab would need to see close to a clinically-implausible +1.0 slope between Wk48-96 in order to reverse

overall eGFR decline to match the -1.0 'healthy' rate. Even if sibeprenlimab leads to a -1.0 rate between Wk48-96,

Otsuka will likely end up with a drug with a -2.0 profile, falling short of expectation on eGFR. While we are not

entirely confident that Vera would be able to exactly replicate the strong -0.6 observed in Origin 2b study, we believe

the clinical advantage of atacicept over sibeprenlimab is significant. Less is known about Vertex's povetacicept, but

we believe Vertex would also be advantaged.

As for why sibeprenlimab posted weak data, three scenarios:

1.