Prime Gene Therapeutics: Pioneering Topical Innovations to Unlock the Billion-Dollar Immune and Inflammatory Disease Market

As our understanding of disease pathogenesis deepens, we are finding that an increasing number of diseases are linked to the immune system.

Immune-mediated diseases can be broadly categorized into allergic diseases and autoimmune diseases. According to data from Frost & Sullivan, the market size for allergic disease medications in China will reach RMB 64.1 billion in 2025. From 2025 to 2030, this market is projected to grow at a compound annual growth rate (CAGR) of 11.0%, reaching an estimated RMB 108.2 billion. Meanwhile, the autoimmune disease segment represents a similarly promising blue-ocean market, with its drug market size in China expected to reach RMB 58.1 billion in 2025. From 2025 to 2030, this market is forecast to expand at a CAGR of 23.1%, reaching an estimated RMB 164.3 billion.

Despite the existence of a blue-ocean market worth hundreds of billions in the field of immune-mediated diseases, currently approved drugs can address only a small fraction of these conditions.Taking autoimmune diseases as an example, there are currently approximately 100 known autoimmune diseases worldwide, with about 5% of the global population suffering from autoimmune inflammation. However, the major targeted therapies currently on the market cover fewer than 30 indications. Consequently, there is an urgent need for the development and approval of drugs for a vast number of remaining indications, as well as for the treatment of a larger pool of clinical patients.

“The human immune system is intricate and complex; although many diseases can be treated by modulating immunity or controlling inflammation,“Sometimes, when you intend to treat only condition A, you may inadvertently trigger adverse reactions associated with condition B. Therefore, topical administration is a rational choice to minimize the toxic side effects of drugs,” Dr. Du Yunlong, CEO and CMO of PrimeGene, told VCBeat.

PrimeGene, established in 2016, is an innovative pharmaceutical company specializing in the development of topical novel drugs targeting immune and inflammatory diseases, with a strategic focus on niche areas such as dermatology, ophthalmology, and rare diseases.

When asked about his reasons for joining PrimeGene, Dr. Du Yunlong recalled, “In the summer of 2020, I had a discussion with the founding team of PrimeGene. At that time, PrimeGene had already begun to rapidly advance the development of its JAK inhibitor. However, the company had not yet clearly defined its future development path and corporate strategy, particularly regarding whether the product would be administered orally or topically.”However, oral JAK inhibitors may cause many potential serious adverse reactions, including anemia, infection, dyslipidemia, and malignancies, and have been issued a black box warning by the FDA.

“At that time, and even now, China has yet to produce a leading enterprise in innovative topical medications.”“So I proposed to the founding team that we position PrimeGene as an innovative topical pharmaceutical company focused on immune and inflammatory diseases. The idea was well received at the time, and indeed, PrimeGene has been striving in this direction over the past few years,” Dr. Du Yunlong told VCBeat.

Prior to joining PrimeGene, Dr. Du Yunlong had nearly 30 years of experience in the end-to-end management of drug R&D, clinical development, and product commercialization. He is the inventor of 15 patents and the author of 21 publications, with extensive expertise in clinical research, medical affairs, clinical pharmacology, and drug safety management. Dr. Du has broad clinical development experience in the fields of nephrology, dermatology, central nervous system (CNS) disorders, smoking cessation, and allergic rhinitis. He has also played a pivotal role in the drafting, preparation, and submission of New Drug Applications (NDAs), contributing significantly to the clinical development and regulatory approval of multiple novel drugs.

After completing his studies in the United States and finishing his postdoctoral research at Weill Cornell Medicine, Dr. Yunlong Du joined a biotech company in New York, where he was responsible for the research and development of innovative topical drugs as well as scientific affairs, “from early-stage molecular screening and animal studies through to Phase II clinical trials.”

In addition to managing end-to-end drug R&D processes at biotech firms, Dr. Yunlong Du has previously held positions at multiple international pharmaceutical companies, including Pfizer and GlaxoSmithKline, where he led preclinical, early-stage clinical, and Phase III clinical studies.

During his tenure at GSK, Dr. Du Yunlong was deeply impressed by a project that involved transitioning the prescription drug Flonase Allergy Relief nasal spray to over-the-counter status.

“This transition is not merely a matter of switching to an OTC label; it involves numerous issues, including safety and patient market accessibility. In terms of market accessibility alone, over-the-counter (OTC) drugs are typically purchased by patients after they have self-diagnosed their symptoms, which requires that patients possess a thorough understanding of disease symptoms and drug indications. Furthermore, extensive education on the safe use of OTC medications for patients is also essential.”“This project has reshaped my previous understanding of drug development. It means that product development must be patient- and market-driven, rather than being pursued solely from a scientific or mechanistic perspective,” explained Dr. Du Yunlong.

Leveraging his mastery of the entire drug development process and a renewed understanding of product commercialization, Dr. Du Yunlong returned to China in 2017 to join Hua Medicine as Senior Vice President, where he assumed overall responsibility for drug safety and pharmacovigilance, New Drug Application (NDA) submissions, and clinical R&D. He made significant contributions to Hua Medicine’s listing on the Main Board of the Hong Kong Stock Exchange in 2018 and the approval and market launch of its drug, Huatangning®.

Today, Dr. Du Yunlong also aims to leverage his extensive R&D experience and advanced management philosophy, fully capitalizing on his expertise in clinical trials and late-stage development of new drugs. His goal is to help PrimeGene grow into a leading Chinese pharmaceutical enterprise with global competitiveness, possessing full-chain capabilities in the R&D and industrialization of original topical innovative drugs, thereby completing its transformation from a Biotech to a Biopharma.

Currently, most domestic companies developing JAK inhibitors are focused on the oral drug segment for conditions such as rheumatoid arthritis, ulcerative colitis, systemic lupus erythematosus, psoriasis, alopecia areata, and moderate-to-severe atopic dermatitis.Due to the FDA's black box warning for JAK inhibitors, the development of oral medications for these diseases has become significantly more challenging, and competition is intense.

Facing such fierce competition, Dr. Du Yunlong said, “A storm is coming; we should think about how to take shelter from the rain, rather than be knocked down by the storm.”

Looking back now, three years ago PrimeGene decided to focus on innovative topical drugs in the field of immune and inflammatory diseases,“This decision was highly prudent, as it carved out a distinctly differentiated path and enabled early entry into a blue ocean market.”

PrimeGene utilizes topical formulations, such as gels, nasal sprays, and eye drops, to avoid the systemic exposure risks associated with conventional oral JAK inhibitors, thereby maintaining clinical compliance, reducing toxic side effects, and making them suitable for long-term use.

Amid dynamic market competition and clinical demands, PrimeGene has established a comprehensive Quality Management System (QMS) for innovative drug R&D and industrialization, structured in accordance with Biopharma standards. This system encompasses biology, medicinal chemistry, pharmacology and toxicology, synthetic process development, pharmaceutical formulation, drug analysis, regulatory affairs, clinical medicine, clinical operations, pharmacovigilance, project management, quality assurance, and commercial operations.

In addition to the advantages of its comprehensive and advanced end-to-end system, PrimeGene has established a new drug design and discovery technology platform, a topical formulation R&D platform, and a clinical translational medicine platform for immune and inflammatory diseases.

Based on the aforementioned system and platform,PrimeGene holds differentiated advantages in the development of topical formulations and the design of topical drug compounds.Formulation technology plays a crucial role in drug absorption. In recent years, PrimeGene has independently developed various dosage forms with penetration-enhancing and solubility-promoting functions, including gels, latexes, creams, ointments, and suspensions. Furthermore, unlike other innovative pharmaceutical companies founded on a biotechnology background, PrimeGene was established as a company with a chemistry background. Therefore, it possesses certain advantages in compound design and synthesis, enabling the development of source-innovative compounds based on specific targets.

Regarding source innovation in drug development, Dr. Du Yunlong believes it has two layers of meaning. One refers to the discovery and innovation of targets or mechanisms that are more oriented toward scientific research; this is typically not an area where pharmaceutical companies excel, and not all innovative targets or mechanisms are suitable for translation. The innovation at which pharmaceutical companies excel lies in rapidly designing compounds or other drugs and therapies based on these targets and mechanisms. ““Pharmaceutical companies engage in application-oriented innovation, developing related products based on a specific ‘point.’”

“I often say that we are fixing the car while driving it, and yet we must drive it as fast as possible,” Dr. Du Yunlong remarked with a smile.

"Under the premise of striving for both speed and stability, PrimeGene has rapidly established a pipeline of seven projects covering therapeutic areas including dermatology, ophthalmology, and respiratory diseases, with multiple indications currently in clinical stages."

PrimeGene’s core investigational compound is PG-011 (pumecitinib), a selective JAK1/2 small-molecule inhibitor. In addition to its broad-spectrum and potent immunosuppressive and anti-inflammatory activities, it also exhibits strong effects on targets associated with skin repair, making it the first JAK multi-functional small-molecule compound to enter clinical trials that integrates anti-inflammatory, immunomodulatory, and tissue-repair properties.

In terms of R&D pipeline progress, PrimeGene’s topical PG-011 gel is among the leading candidates in the Chinese market. The Phase IIb clinical trial for treating mild-to-moderate atopic dermatitis (AD) has been completed, with results demonstrating that PG-011 gel significantly improves AD symptoms while exhibiting minimal systemic absorption, thereby indicating an excellent safety profile. PrimeGene is expected to initiate Phase III clinical trials for the treatment of mild-to-moderate atopic dermatitis in early next year.

According to Frost & Sullivan data, the market for atopic dermatitis (AD) drugs in China is projected to reach approximately RMB 12.63 billion in 2025. Despite this substantial blue-ocean market, currently available innovative drugs in China are primarily indicated for patients with moderate-to-severe AD, leaving few innovative topical options for those with mild-to-moderate disease. Mainstream topical therapies—including corticosteroids, calcineurin inhibitors, and PDE4 inhibitors—each have their own limitations. A novel, non-hormonal topical JAK inhibitor with a new mechanism of action, high safety profile, and strong efficacy would provide a better therapeutic option for AD patients.

In addition to treating mild-to-moderate atopic dermatitis (AD), PrimeGene has currently undertaken R&D efforts for the PG-011 molecule across multiple formulations and indications. The Phase II clinical trial of PG-011 gel for the treatment of prurigo nodularis has been completed, and the Phase II clinical trial of PG-011 nasal spray for seasonal allergic rhinitis is scheduled to launch in the near future. Other clinical pipeline programs centered on PG-011 for conditions such as solar dermatitis, radiation dermatitis, vitiligo, and rare diseases are also advancing rapidly. In terms of pipeline development, while adopting a “Fast Follower” strategy to mitigate R&D risks, PrimeGene has also selected certain “First-in-Class” targets to enhance innovation and lay the foundation for its future global expansion.

Regarding the company’s future development, Dr. Du Yunlong summarized,“PrimeGene has already completed its listing on the New Third Board and is expected to initiate its IPO filing next year. In two to three years, we anticipate submitting multiple NDAs and commencing commercial production of our products.” 

From selecting the innovative topical drug sector, to continuously advancing R&D progress, and then to preparing for commercialization, as a company focused on developing clinically valuable innovative topical medications and committed to benefiting patients worldwide, we look forward to PrimeGene continuing to blaze new trails in its R&D and future commercialization journey, bringing forth a path blooming with success.