Biogen Begins Phase III Felzartamab Study for Third Kidney Disease

Biogen BIIB initiated dosing in a global, late-stage study of its investigational candidate, felzartamab, for treating adult patients with primary membranous nephropathy (PMN). Top-line data readout is expected in 2029.

Felzartamab is an anti-CD38 antibody with a unique mechanism of action that is particularly relevant in PMN treatment. Currently, no approved therapies exist for PMN, and treatment typically relies on immunosuppressants or chemotherapy.

Felzartamab was added to Biogen’s pipeline with the acquisition of Human Immunology Biosciences (HI-Bio) last year. The candidate was originally developed by MorphoSys AG (acquired by Novartis), which out-licensed exclusive rights to develop and commercialize felzartamab to HI-Bio across all indications in all countries and territories, excluding China and certain other geographies.

BIIB’s Phase III PMN Study Design for Felzartamab

Biogen’s global phase III PROMINENT study will evaluate the efficacy and safety of felzartamab compared to an immunosuppressive drug, tacrolimus, in moderate-to-high-risk PMN patients in achieving complete remission of proteinuria (high levels of protein in the urine). The patient pool will include both newly diagnosed and relapsed cases.

Year to date, BIIB shares have plunged 17.9% compared with the industry’s decline of 3.6%.

Biogen expects to enroll approximately 180 PMN patients in the PROMINENT study who will be randomized to receive either felzartamab or tacrolimus, with the primary endpoint being the percentage of patients who achieve complete remissions at week 104. The study will evaluate patients with and without a certain antibody (called anti-PLA2R) linked to PMN. Patients will be grouped based on how much of this antibody they have. As secondary endpoints, BIIB will also evaluate the effect of felzartamab on serum aPLA2R antibodies and patient-reported outcomes.

PMN is a serious kidney disease that can lead to kidney failure and affects about 36,000 people in the United States. It causes severe swelling, fatigue and infection risk. There are no approved treatments, and current options like immunosuppressants or chemotherapy fail in about one-third of patients, representing a serious unmet medical need.

In 2025, Biogen has also initiated dosing patients with felzartamab in two other phase III studies, TRANSCEND for late antibody-mediated rejection in adult kidney transplant recipients and PREVAIL for IgA nephropathy.

BIIB’s Felzartamab Shows Promise in Prior Studies

Biogen previously evaluated felzartamab in two phase II studies, M-PLACE and NewPLACE, focusing on patients with aPLA2R-positive PMN. In M-PLACE, most patients showed a significant drop in aPLA2R antibody levels within a week (median reduction of 45%), with most achieving more than 50% reduction by six months. The treatment also led to improvements in protein levels in urine and blood.

In both studies, side effects were primarily mild to moderate in severity and aligned with the candidate’s expected safety profile. The most common adverse event was infusion-related reactions following the first dose.

Biogen Inc. Price and Consensus

Biogen Inc. price-consensus-chart | Biogen Inc. Quote

BIIB’s Zacks Rank & Stocks to Consider

Biogen currently carries a Zacks Rank #4 (Sell).

Some better-ranked stocks in the biotech sector are Immunocore IMCR, Verona Pharma VRNA and Agenus AGEN. While IMCR and VRNA sport a Zacks Rank #1 (Strong Buy) each, AGEN carries a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

In the past 90 days, loss per share estimates for Immunocore’s 2025 have improved from $1.57 to 86 cents. Loss per share estimates for 2026 have narrowed from $1.80 to $1.33 during the same period. IMCR stock has gained 6.4% year to date.

Immunocore’s earnings beat estimates in three of the trailing four quarters and missed the mark once, delivering an average surprise of 76.18%.

In the past 90 days, Verona Pharma’s bottom-line estimates for 2025 have significantly improved from a loss of 7 cents per share to earnings of 22 cents. During the same timeframe, estimates for 2026 earnings per share have improved from $2.21 to $2.88. VRNA stock has surged 103.7% so far this year.

Verona Pharma’s earnings beat estimates in one of the trailing four quarters and missed the mark on the other three occasions, delivering an average negative surprise of 6.76%.

In the past 90 days, Agenus’ bottom-line estimates for 2025 have significantly improved from a loss of $4.66 per share to earnings of $1.56. During the same timeframe, estimates for 2026 loss per share have narrowed from $5.02 to $1.99. AGEN stock has soared 66.8% so far this year.

Agenus’ earnings beat estimates in two of the trailing four quarters and missed the mark on the other two occasions, delivering an average negative surprise of 22.71%.

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