On August 27, Rongchang Biopharma announced that its independently developed world's first BLyS/APRIL dual-target fusion protein innovative drug Taitasip (trade name: Tai Ai®) for the treatment of primary immunoglobulin A (IgA) nephropathy reached the primary study endpoint of Phase A in the domestic Phase III clinical study.

Study results showed that compared with the placebo group, patients in the tetasip group experienced a 55% reduction in 24-hour urine protein-to-creatinine ratio (UPCR) at week 39 of treatment (P<0.0001), demonstrating good tolerability and safety. Rongchang Biopharma stated that it will submit a marketing application to the National Medical Products Administration (NMPA) as soon as possible, and detailed data will be presented at a major international academic conference.

This multicenter, randomized, double-blind, placebo-controlled Phase III clinical trial enrolled 318 adult patients with IgA nephropathy receiving standard treatment. Tetasipir was administered at a dose of 240 mg subcutaneously once weekly. The study aimed to evaluate the efficacy and safety of Tetasipir in the treatment of IgA nephropathy through two phases, A and B. Phase A evaluated the change from baseline in 24-hour UPCR before and after 39 weeks of treatment with Tetasipir or placebo to verify the efficacy and safety of Tetasipir in reducing proteinuria.

IgA nephropathy is one of the most common primary glomerular diseases worldwide and a leading cause of chronic kidney disease and renal failure. According to Frost & Sullivan, the number of IgA nephropathy patients worldwide is expected to reach 10.16 million by 2030, including 2.37 million in my country. IgA nephropathy patients in my country account for approximately 54.3% of all renal biopsy cases, and 30%-40% of these patients will progress to end-stage renal disease (ESRD), resulting in a significant disease burden.

In traditional treatment options, glucocorticoids and immunosuppressants are the mainstays of IgA nephropathy treatment. However, long-term use of glucocorticoids is associated with numerous adverse reactions, such as increased risk of infection, osteoporosis, and moon facies. Immunosuppressants also have numerous side effects. For example, cyclophosphamide may cause bone marrow suppression and hemorrhagic cystitis, and are generally not used clinically for mild cases of renal disease.

In recent years, with the deepening of research on the pathogenesis of IgA nephropathy, some targeted drugs have begun to emerge.

Currently, tetasip is the only drug that can simultaneously inhibit B lymphocyte stimulator (BLyS) and proliferation-inducing ligand (APRIL). These two cytokines, which are significantly higher in patients with IgA nephropathy than in the healthy population, are key drivers of the disease. By inhibiting these two factors, tetasip can reduce B cell proliferation, plasma cell numbers, and abnormal immunoglobulin production, blocking immune complex deposition at the source and alleviating renal immune inflammatory responses.

In addition to IgA nephropathy, tetasip is also being developed for the treatment of a variety of other autoimmune diseases. In 2021, the drug was approved for the treatment of systemic lupus erythematosus, and in 2024 for rheumatoid arthritis. In May of this year, it was approved for the blockbuster indication of myasthenia gravis (MG).

In addition, earlier this month, the Phase III clinical study of tetasip for the treatment of Sjögren's syndrome (pSS) also achieved the primary study endpoint: it can sustainably and effectively improve the clinical symptoms of patients with Sjögren's syndrome and show good efficacy and safety.

On the BD side, in June of this year, Rongchang Biopharma and Vor Bio reached a collaboration, under which Vor Bio will obtain exclusive rights to develop, manufacture, and commercialize tadalafil globally, excluding Greater China. Rongchang Biopharma received $125 million in cash and warrants from Vor Bio (including a $45 million down payment and an $80 million warrant, representing approximately 23% of Vor Bio's enlarged issued and outstanding share capital), as well as milestone payments of up to $4.105 billion, for a total of $4.23 billion. In addition, Rongchang Biopharma will receive high-single-digit to double-digit sales royalties.

Currently, Tetasip has received Fast Track Designation (FTD) from the US FDA and Orphan Drug Designation (ODD) from both the US and EU regulatory agencies for the treatment of MG. In August 2024, the first patient was successfully enrolled in an overseas Phase III clinical study, and enrollment is ongoing.

Conclusion: According to Rongchang Biopharma's latest financial report, Taitasip achieved sales revenue of 650 million yuan in the first half of this year. With the promotion of the newly approved gMG indication and the success of more blockbuster indications, the drug is expected to achieve accelerated sales growth in the future and become the core driving force for the company's long-term growth.