Vertex Pharmaceuticals presented updates on its kidney disease programs at the American Society of Nephrology (ASN) Kidney Week Congress, highlighting the potential of its investigational therapies for IgA nephropathy (IgAN), primary membranous nephropathy (pMN), and APOL1-mediated kidney disease (AMKD).
Povetacicept Shows Promise in IgAN and pMN
New data on povetacicept, a dual inhibitor of the BAFF and APRIL pathways, were presented for both IgAN and pMN. In IgAN patients treated with povetacicept 80 mg subcutaneously every four weeks, a mean reduction of 66% in urine protein to creatinine ratio (UPCR) from baseline was observed at 48 weeks (n=8). This was associated with stable renal function, as assessed by estimated glomerular filtration rate (eGFR). Furthermore, 63% of participants achieved clinical remission, defined as UPCR <0.5 g/g, negative hematuria, and stable renal function.
Similar improvements in proteinuria and stable renal function were observed with a 240 mg dose. The drug was well-tolerated, with most adverse events being mild to moderate and no serious adverse events related to the treatment.
In pMN, early data showed that povetacicept 80 mg administered subcutaneously every four weeks led to a mean 62% reduction from baseline in UPCR at 24 weeks. 67% of study participants achieved partial clinical remission, defined as UPCR <3.5 g/g and >50% reduction in UPCR from baseline. Anti-PLA2R1 autoantibodies, a marker of disease activity, decreased by a mean of 87% at week 20. Povetacicept was also well-tolerated in pMN patients.
Phase 3 Trial of Povetacicept in IgAN Initiated
Vertex has initiated RAINIER, a global Phase 3 clinical trial evaluating povetacicept 80 mg in approximately 480 patients with IgAN. The study includes a pre-planned interim analysis to assess UPCR, potentially serving as the basis for accelerated approval in the U.S. The primary endpoint of the final analysis, conducted after two years of treatment, will be the total eGFR slope through Week 104.
Inaxaplin Development for AMKD Progresses
Vertex is also developing inaxaplin, an oral small molecule inhibitor of APOL1, to target the underlying cause of AMKD. Enrollment and dosing are ongoing in the Phase 3 portion of the AMPLITUDE clinical trial.
"We are very pleased with the broadening of our innovative pipeline in renal medicine which now spans programs in AMKD, IgAN, pMN and polycystic kidney disease," said Carmen Bozic, M.D., Executive Vice President, Global Medicines Development and Medical Affairs, and Chief Medical Officer at Vertex. "The new data in IgAN and pMN we shared at this year’s ASN congress continue to reinforce povetacicept as a potential best-in-class therapy and demonstrate its potential as a pipeline-in-a-product."
