Revenue decreased by 33.8% year-over-year. How is CStone Pharmaceuticals' investment in the progress of the triple antibody pipeline?

Can AI · CS2009’s triple antibody data become the key to a performance turnaround?

21st Century Business Herald Reporter Han Liming Intern Jiang Yutong

After achieving its first profit in the first half of 2024 and continuously improving its annual financial performance, CStone Pharmaceuticals (2616.HK) saw its 2025 results decline again. The annual report shows that the company achieved revenue of 270 million yuan in 2025, down 33.8% year-on-year; net loss expanded to 437 million yuan, an increase of 346 million yuan compared to a loss of 91 million yuan in 2024.

Against the backdrop of performance pressure, CStone Pharmaceuticals also disclosed the latest development progress and key Phase I/II clinical data of the PD-1/VEGF/CTLA-4 triple-specific antibody CS2009. Dr. Yang Jianxin, CEO, R&D President, and Executive Director of CStone, stated that more Phase I and II data are expected to be announced at this year’s ASCO and/or ESMO conferences. The company is currently in in-depth negotiations with multiple global multinational corporations (MNCs) for cooperation and plans to initiate multiple Phase III MRCT (International Multicenter Clinical Trials) studies before the end of 2026.

Buoyed by the above pipeline progress news, since March 26, CStone’s stock price has shown oscillating upward momentum, with a single-day increase of 20.72% on March 27, closing at HKD 8.33 per share. As of the close on April 1, the stock further rose by 5.29%, closing at HKD 9.16 per share, with a total market value climbing to HKD 13.52 billion.

An industry insider told the 21st Century Business Herald that since 2025, PD-1 (L1)/VEGF dual antibodies have gradually become phenomenon-level products, potentially becoming new cornerstone drugs for tumor immunotherapy. Multiple business development (BD) transactions have helped these products gain global popularity. Under this trend, many pharmaceutical companies are proactively布局 in the triple antibody field, and the market is paying attention to whether PD-(L)1/VEGF triple antibodies can sustain the industry heat.

Image source: CStone Pharmaceuticals 2025 Annual Report

Revenue decline

Currently, CStone Pharmaceuticals has four marketed innovative drugs, including Sugemalimab, Avasitinib, Pritinib, and Efluvirtide.

Among them, on December 21, 2023, CStone reached an agreement with SviYarda to sell exclusive rights for the development, production, and commercialization of Efluvirtide in Greater China and Singapore. According to the agreement, CStone transferred related rights for USD 44 million, and after the transaction transfer, will additionally receive USD 6 million.

This also means that in 2025, CStone’s drug sales revenue mainly came from Avasitinib, Pritinib, and Sugemalimab, totaling 78.3 million yuan. Compared to 2024, when only Avasitinib and Pritinib generated sales of 175.1 million yuan, the decline in drug sales revenue in 2025 is obvious.

CStone explained in its annual report that the significant decline in Pritinib sales was mainly due to the company’s price adjustments in preparation for national medical insurance drug list negotiations, along with related one-time channel compensation payments.

Pritinib is China’s first-in-class translocation/rearrangement (RET) inhibitor and the first RET inhibitor approved for listing in mainland China. Currently, CStone has not disclosed the price adjustment range for Pritinib. However, last year, information revealed that Eli Lilly’s RET inhibitor Caprevecin capsules decreased from 32,833.5 yuan to 18,600 yuan, a 43% price reduction.

Nevertheless, CStone expects that the revenue growth of Pritinib in 2026 and beyond will offset the short-term negative impact caused by the price adjustment in 2025. It is worth noting that, besides the pressure from price reductions, Pritinib will also face increasingly fierce market competition.

Public data shows that Kelun-Biotech’s Fumaric acid Lumbotinib capsules and Sihuan Pharmaceutical’s Sotoritinib tablets received acceptance in September and October 2025, respectively, both for treating RET fusion-positive locally advanced or metastatic non-small cell lung cancer (NSCLC) in adult patients.

Additionally, according to an exclusive agreement signed in November 2023, the exclusive commercialization rights for Pritinib in mainland China were transferred to Shanghai Ailis in the first half of 2024.

In fact, CStone has licensed out the commercialization rights of several core products. In 2024, CStone granted Jiangsu Hengrui Medicine exclusive promotion rights for Avasitinib in mainland China, while retaining rights for development, registration, manufacturing, and distribution. Under the agreement, CStone received an upfront payment of 35 million yuan.

Benefiting from multiple collaborations in 2024, CStone achieved licensing fee income of 204 million yuan that year; in 2025, licensing fee income decreased to 168 million yuan, a year-on-year decline. The company explained in its financial report that this was mainly due to the large upfront and milestone payments received in 2024.

For Sugemalimab, CStone also reached strategic commercialization collaborations with SteinCares in 10 Latin American countries; in July of the same year, it also partnered with Gentili for commercialization in 23 Western European countries and the UK. Currently, Sugemalimab has established four partnership relationships.

However, the licensing fee income from Sugemalimab also declined. CStone disclosed that in 2025, this product generated licensing fee income of 23.6 million yuan, compared to 28.1 million yuan in 2024, a year-on-year decrease.

Betting on triple antibodies pipeline?

While performance remains under pressure, CStone has “ignited the market” with the latest clinical data of CS2009.

Public data shows that CS2009 is the world’s first triple antibody targeting the same target to enter clinical stages. In October 2025, CStone disclosed Phase I clinical data: among 72 patients with advanced solid tumors, no dose-limiting toxicities occurred, the maximum tolerated dose was not reached, and the incidence of grade 3 or higher treatment-related adverse events was only 13.9%, far lower than similar dual antibodies. In terms of efficacy, at the provisional Phase II recommended dose and higher doses, the objective response rate (ORR) reached 25.0%; in the NSCLC subgroup with driver gene negativity, ORR was also 25%.

Recently, CStone announced that as of mid-March 2026, 113 patients with advanced solid tumors had been enrolled in the Phase I trial of CS2009, with a ≥3 grade treatment-related adverse event rate of 23%, and no severe toxicity was observed in combination therapy with CTLA-4 and PD-(L)1.

Moreover, in first-line NSCLC (PD-L1 TPS ≥50%) patients with tumor cell positivity, the ORR reached 90%, and disease control rate was 100%. In second-line and later NSCLC patients who had undergone immunotherapy and were driver gene-negative, ORR was 25%.

Guoyuan International’s research report pointed out that (CS2009) triple antibodies show excellent single-agent data in lung cancer, with an ORR of 90% in first-line NSCLC (PD-L1 TPS ≥50%), leading similar products, and with excellent safety. As more clinical data are released, the company is expected to accelerate cooperation with MNCs and speed up multiple pipeline global Phase III clinical trials.

In fact, in May 2025, Sanofi announced a $1.25 billion prepayment and $4.8 billion milestone payments to license the global rights outside China for PD-1/VEGF dual antibody SSGJ-707 to Pfizer, breaking the record for upfront payments for Chinese pharmaceutical product exports, igniting the market enthusiasm for PD-1 (L1)/VEGF dual antibodies, and industry continues to look forward to the next major BD deal.

Building on the rapid development of dual antibodies, triple antibody drugs are gradually entering clinical stages. Besides CStone, on March 3, 2026, Huadong Medicine announced that its subsidiary Zhejiang Daorong Biotech’s injectable DR30206 was approved to enter clinical trials, combined with standard chemotherapy for patients with locally advanced or metastatic NSCLC. It is reported that DR30206 is an antibody fusion protein targeting PD-L1, VEGF, and TGF-β.

For CStone, besides CS2009, it is also advancing the development of several innovative drugs such as CS5001 (ROR1 ADC), CS5005 (SSTR2 ADC), and CS5006 (ITGB4 ADC), with a pipeline of 16 candidate drugs. However, as of the end of 2025, the company’s cash and cash equivalents and time deposits totaled only 919 million yuan.

For innovative drug companies with high R&D costs and long return cycles, balancing R&D investment and cash flow safety is a critical issue CStone currently faces. Moving forward, with continuous clinical data updates, successful BD collaborations, and increased healthcare coverage, whether the company can achieve a performance turnaround remains a key market focus.