Sanofi's Experimental Transplant Rejection Drug Gets FDA Orphan Tag

Sanofi SNY announced that the FDA has granted orphan drug designation to its investigational drug, riliprubart, for the treatment of antibody-mediated rejection (AMR) in solid organ transplantation.

How Does the Orphan Tag Benefit SNY’s Drug Development?

Orphan drug designation is granted by the FDA to therapies intended for the treatment of rare diseases or conditions affecting fewer than 200,000 people in the United States. The goal is to encourage drug development for rare diseases or conditions by offering incentives such as tax credits for clinical testing, waiver of certain fees and most importantly, seven years of market exclusivity upon approval.

For Sanofi, this designation provides riliprubart with important regulatory and financial advantages as it advances through clinical development for AMR in solid organ transplantation — a serious complication where the immune system attacks the donated organ. Currently, there are no FDA-approved therapies for this condition. The designation may help accelerate progress and reduce the development burden as Sanofi works to address this critical unmet need in transplant medicine.

SNY Stock Price Performance

Shares of Sanofi have outperformed the industry year to date, as seen in the chart below.

More on Sanofi’s Riliprubart

An investigational IgG4 humanized monoclonal antibody, riliprubart is designed to selectively inhibit activated C1s in the classical complement pathway of the innate immune system.

The drug is currently being evaluated in a mid-stage study for AMR in kidney transplant recipients across two patient groups — those at risk of developing rejection and those already experiencing active AMR.

Apart from AMR, Sanofi is also evaluating riliprubart in two late-stage studies — MOBILIZE and VITALIZE — for a rare neurological disorder called chronic inflammatory demyelinating polyneuropathy (CIDP). While the MOBILIZE study targets patients for whom standard-of-care treatments do not work, the VITALIZE study compares the drug against intravenous immunoglobulin (IVIg).

CIDP is a rare disorder affecting the peripheral nervous system, marked by progressive muscle weakness and sensory loss. Notably, riliprubart has also received orphan drug designation in both the United States and EU for its prospective use in CIDP, highlighting its potential across multiple immune-mediated diseases.

SNY’s Zacks Rank

Sanofi currently carries a Zacks Rank #3 (Hold).

Sanofi Price

 

Sanofi price | Sanofi Quote

Key Picks Among Biotech Stocks

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

In the past 60 days, loss per share estimates for Amarin’s 2025 have improved from $5.01 to $2.50. Loss per share estimates for 2026 have narrowed from $3.84 to $1.78 during the same period. AMRN stock has surged nearly 65% year to date.

Amarin’s earnings beat estimates in two of the trailing four quarters, met the mark once and missed in the other, delivering an average surprise of 29.11%.

In the past 60 days, loss per share estimates for Immunocore’s 2025 have improved from $1.50 to 86 cents. Loss per share estimates for 2026 have narrowed from $1.68 to $1.33 during the same period. IMCR stock has gained nearly 9% 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 60 days, Agenus’ bottom-line estimates for 2025 have significantly improved from a loss of $3.46 per share to earnings of $1.56. During the same timeframe, estimates for 2026 loss per share have narrowed from $3.91 to $1.99. AGEN stock has soared 83% 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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