Southwest Securities has released a research report stating that PD-(L)1 inhibitors are undergoing a critical transition from "widespread adoption" to "post-treatment iteration." In the post-PD-1 era, innovative drug developers are focusing on three major R&D strategies: novel combination therapies, new technologies, and new targets. The primary investment themes for the industry in 2026 will revolve around three types of assets: cytokine fusion proteins and novel checkpoint platforms with First-in-Class/Best-in-Class potential; leading PD-(L)1 bispecific/multispecific antibody developers that have entered the registration/commercialization realization phase; and Antibody-Drug Conjugates (ADCs) demonstrating clear efficacy inflection points in post-IO treatment lines. The main views of Southwest Securities are as follows:
PD-(L)1 Market Not Yet Peaking, Undergoing Key Transition from Widespread Adoption to Post-Treatment Iteration
Global PD-(L)1 market sales reached $56.7 billion in 2025, with a CAGR of approximately 44% from 2015 to 2025, marking a decade-long leap from an emerging therapy to a cornerstone of first-line oncology treatment. As the clinical application of PD-(L)1 monoclonal antibodies becomes increasingly widespread, the industry's core challenges are gradually shifting from the early "validation of efficacy" to three key issues: "addressing primary/acquired resistance, overcoming challenges in 'cold' tumors, and extending survival benefits for patients in later lines of therapy." Post-PD-1 treatment resistance is poised to become a high-demand, cost-effective "blue ocean" indication. 1) The existing patient base is large and continues to grow: 80% of patients do not benefit from PD-(L)1 monotherapy, and patients receiving first-line IO therapy will eventually experience disease progression. 2) Resistance mechanisms are complex, and treatment options for later lines remain unclear: The efficacy of re-challenging with immunotherapy post-IO treatment declines significantly, with an Objective Response Rate (ORR) of less than 20%.
New Drug Strategies in the Post-PD-1 Era: Novel Combinations, New Technologies, New Targets
When patients experience disease progression after chemotherapy combined with immunotherapy, the standard second-line regimen is a return to chemotherapy, such as docetaxel with or without anti-angiogenic agents. While returning to chemotherapy alone is effective, its benefits are limited, and toxicity cannot be ignored. Globally, there remains a long-term lack of high-level, large-sample, targeted evidence-based medical data, meaning the market pain point of post-PD-1 treatment resistance remains unresolved. In the post-PD-1 era, innovative drug developers are focusing on three major R&D strategies: novel combination therapies, new technologies, and new targets. Among these, combination therapies (e.g., PD-(L)1 + chemotherapy/CTLA-4/LAG-3/TIGIT/VEGF) represent improvements to the tumor microenvironment; bispecific antibodies represent the upgrade from PD-1 monoclonal antibodies to "PD-(L)1 2.0"; and ADCs represent the precise replacement for chemotherapy. Currently, Akeso Inc.'s AK104 combined with plozalizumab (a VEGFR2 mAb) has achieved the longest Overall Survival (OS) among the disclosed research data for IO-treated lung cancer, with a median OS (mOS) of 16.7 months.
2026: A Pivotal Year for Transitioning from Proof-of-Concept to Valuation Realization, with Highly Concentrated Catalysts
The primary investment themes for the industry in 2026 will revolve around three types of assets: cytokine fusion proteins and novel checkpoint platforms with First-in-Class/Best-in-Class potential; leading PD-(L)1 bispecific/multispecific antibody developers that have entered the registration/commercialization realization phase; and Antibody-Drug Conjugates (ADCs) demonstrating clear efficacy inflection points in post-IO treatment lines. 1) Akeso Inc.: The mOS data for ivonescimab (HARMONi) is not yet mature. Based on positive results from the Phase III HARMONi study in second-line EGFR-mutant Non-Small Cell Lung Cancer (NSCLC), Summit announced on January 12, 2026, the formal submission of a Biologics License Application (BLA) to the FDA for ivonescimab combined with chemotherapy, with a PDUFA date response expected by November 14 at the latest. Partial data for cadonilimab was presented at ELCC 2026, with full data expected to be disclosed subsequently. 2) CStone Pharmaceuticals: Partial Phase I clinical data for CS2009 in post-treatment resistant lines was presented at ASCO 2026 (May 29 - June 2), with further readouts expected at ESMO 2026 (October 23-27). 3) Innovent Biologics, Inc.: Phase I data for IBI363 and IBI343 in IO-treated patients were both presented at the ASCO 2026 conference. 4) Kelun-Biotech Pharmaceutical Co., Ltd.: Full data from the Phase III TroFuse-005 study for Sac-TMT was presented at the ASCO 2026 conference. Additionally, Phase I/II data for PM8002 (Pumiss) combined with a HER3 ADC for second-line solid tumor treatment, Phase III data for Pfizer's ITG86 ADC, among others, are expected to be read out in 2026.
Recommended companies to watch include: Akeso Inc., Kelun-Biotech Pharmaceutical Co., Ltd., 3SBio Inc., Innovent Biologics, Inc., and CStone Pharmaceuticals.
Risk warnings include: risks of R&D progress falling short of expectations, risks of worsening competitive landscape, risks of market promotion underperformance, and policy risks.
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