Pliant Therapeutics, Inc. · NASDAQ:PLRX

Pliant Therapeutics — Investor Presentation (September 2026)

24 slides from Pliant Therapeutics's investor presentation, September 2026

1. Slide 1: Advancing Novel, Targeted Integrin-Based Therapies

   ADVANCING NOVEL, TARGETED INTEGRIN-BASED THERAPIES SEPTEMBER 2026 © 2026 PLIANT THERAPEUTICS

2. Slide 2: Disclaimers

   Disclaimers This presentation has been prepared by Pliant Therapeutics, Inc. ("we," "us," "our," "Pliant" or the “Company”). The information set forth herein does not purport to be complete or to contain all of the information you may desire. Statements contained herein are made as of the date of th

3. Slide 3: Near-term Oncology Opportunity with Long-Term Platform Potential

   Near-term Oncology Opportunity with Long-Term Platform Potential PLN-101095: Oral αvβ8 / αvβ1 Inhibitor New Opportunity for Integrin Platform: for Treatment of ICI-resistant Tumors Cell-selective Drug Delivery • 40% clinical response rate (1 CR and 3 PRs [1 • Emerging cell-specific delivery platform

4. Slide 4: Pipeline

   Pipeline Program Indication Preclinical Phase 1a/1b Phase 2 Phase 3 Global Rights PLN-101095 Solid Tumors αvβ8/αvβ1 inhibitor Muscle INTEGRIN DRUG DELIVERY Adipose Tissue PLATFORM Undisclosed © 2026 PLIANT THERAPEUTICS 4

5. Slide 5: Integrins are an Attractive Target Class

   Integrins are an Attractive Target Class Integrins are extracellular Pliant’s integrin library matrix receptors • Cell surface receptors that facilitate cell- • Broad coverage of integrin heterodimers in cell and cell-extracellular matrix adhesion 15,000+ compound library and interaction • SAR under

6. Slide 6: Integrins Regulate TGF-β Signaling in Solid Tumors

   Integrins Regulate TGF-β Signaling in Solid Tumors vβ8 Integrin Activation of TGF-β • αVβ8 binds latent TGF-β and exposes its active domain without TGF- β being released from its latent complex1,2 • The exposed TGF-β active domain activates the TGF-β receptor αVβ8 while still in the latent complex,

7. Slide 7: Integrin Internalization & Recycling Enables Payload Delivery

   Integrin Internalization & Recycling Enables Payload Delivery Homeostatic Ligand Inducible Integrin Recycling Integrin Internalization Unproductive Delivery Productive Delivery Payload Delivery molecule Recycling Endosome Intracellular Endo-lysosomal Pathway Payload Delivery © 2026 PLIANT THERAPEUTI

8. Slide 8: PLN-101095 – αVβ8 / αVβ1 Dual Integrin Inhibitor

   PLN-101095 – αVβ8 / αVβ1 Dual Integrin Inhibitor Clinical Stage Solid Tumor Program © 2026 PLIANT THERAPEUTICS

9. Slide 9: Potential First-in-Class Oral αVβ8/αVβ1 Inhibitor

   Potential First-in-Class Oral αVβ8/αVβ1 Inhibitor Potent dual inhibitor of αVβ8 and αVβ1 • Tumors that overexpress αVβ8 have a poor prognosis • αVβ1 upregulated on cancer-associated fibroblasts Small molecule - Oral administration • High tissue penetration (vs. biologics) improves target coverage to

10. Slide 10: Secondary Refractory Disease is a Large Underserved Post-ICI Segment

    Secondary Refractory Disease is a Large Underserved Post-ICI Segment ICI Refractory Opportunity ICI / ICI- 1° or 2° regimen BOR Refractory CR Target • ICI regimens are now 1L standard across most major solid tumors Patient Pop. • The success of ICI combinations is increasing the secondary PR refract

11. Slide 11: Differentiated Mechanism with Potential to Unlock the Promise of TGF-β Inhibition

    Differentiated Mechanism with Potential to Unlock the Promise of TGF-β Inhibition Across Solid Tumors In response to sustained immune activity, solid tumors utilize αVβ8 and αVβ1 activation of TGF-β to suppress and escape immune control PLN-101095 designed to: • Selectively block αVβ8 and αVβ1 activ

12. Slide 12: Mechanism of Action in Solid Tumors

    Mechanism of Action in Solid Tumors Promotes ICI Responsiveness by Inhibiting TGF-β & Increasing IFN- Expression By inhibiting TGF-β, PLN-101095 shifts solid tumors to a high IFN-γ signature, ICI-responsive state Tumor Gene Expression Change Anti-PD-(L)1 non-responsive After Treatment baseline gene

13. Slide 13: PLN-101095 Updated Phase 1a Data

    PLN-101095 Updated Phase 1a Data © 2026 PLIANT THERAPEUTICS

14. Slide 14: Summary – Phase 1 Interim Analysis in ICI Refractory Solid Tumors

    Summary – Phase 1 Interim Analysis in ICI Refractory Solid Tumors PLN-101095 showed antitumoral activity with pembrolizumab in ICI secondary refractory participants • 4 clinical responders (1 CR and 3 PRs [1 unconfirmed]) in ICI secondary refractory population1 at doses ≥1000 mg BID • Durable respon

15. Slide 15: Phase 1 Trial in Patients Refractory to ICIs

    Phase 1 Trial in Patients Refractory to ICIs Enrollment Complete with All Doses Cleared PRIMARY AND SECONDARY ENDPOINTS PLN-101095 PLN-101095 Monotherapy Combination with Pembrolizumab • TEAEs, serious TEAEs, and DLT events • PK parameters in monotherapy and combination therapy with pembrolizumab Da

16. Slide 16: Demographics and Baseline Characteristics

    Demographics and Baseline Characteristics • Predominantly white (75%), mixed gender (50% male) population • Average [range] age of 60 [34,72] years • Heterogenous group of tumor types enrolled • Cohorts 1-2 (doses < 1000 mg BID): NSCLC, HNSCC and RCC • Cohorts 3-5 (doses ≥ 1000 mg BID): NSCLC (n=2),

17. Slide 17: PLN-101095 Was Generally Well Tolerated

    PLN-101095 Was Generally Well Tolerated Cohort 1 Cohort 2 Cohort 3 Cohort 4 Cohort 5 250 mg BID 500 mg BID 1000 mg BID 1000 mg TID 2000 mg BID Total n (%) (n=1) (n=2) (n=6) (n=4) (n=3) (n=16) Any TRAE 1 (100) 1 (50) 4 (67) 4 (100) 2 (67) 12 (75) Grade 3/4a 0 0 1 (17)c 0 0 1 (6) Serious 1 (100)b 0 1

18. Slide 18: PLN-101095 Monotherapy Demonstrated Dose-Ordered Exposure at Day 14

    PLN-101095 Monotherapy Demonstrated Dose-Ordered Exposure at Day 14 Total PLN-101095 Concentration, ng/mL 250 mg BID (n=1) 500 mg BID (n=1) 10000 1000 mg BID (n=5) • All participants receiving ≥1000 1000 mg TID (n=4) mg BID maintained IC75 coverage 2000 mg BID (n=3) over 24 hours, supporting IC99 co

19. Slide 19: Clinically Significant, Durable Responses Observed in Responders at Doses ≥1000 mg BID

    Clinically Significant, Durable Responses Observed in 3 of 4 iRECIST Responders at Doses ≥1000 mg BID 100 Dose level Tumor type 80 2000 mg BID Cholangiocarcinoma (1) RCC (1) Change From Baseline in Sum 60 1000 mg TID Cholangiocarcinoma (2) RCC (2) of Target Diameters, % 1000 mg BID Cholangiocarcinom

20. Slide 20: Responses Were Observed in Patients With Secondary ICI Resistance

    Responses Were Observed in Patients With Secondary ICI Resistance Dose level 100 2000 mg BID Four iRECIST Baseline in Target Tumor, % 80 1000 mg TID Maximum Change From 60 respondersa 1000 mg BID 1 CR, 2 PRs and 500 mg BID 40 1 unconfirmed PR 250 mg BID 20 Tumor type 0 Cholangiocarcinoma CRC −20 Par

21. Slide 21: Clinical Response Associated With Elevated Plasma IFN-γ and PD-L1 Levels

    Clinical Response to PLN-101095 Is Associated With Elevated Plasma IFN-γ and PD-L1 Levels After 14 Days’ Monotherapy Change in Plasma IFN-γ Change in PD-L1 Week 2 Mean (±SE) change over 10 weeks Monotherapy 75 Mono- Combination Mean (±SE) change over 10 weeks Responder (n=4) iCR therapy * 1200 Mono-

22. Slide 22: Key Findings and Next Steps

    Key Findings and Next Steps PLN-101095 produced anti-tumor activity in multiple tumor types in ICI secondary refractory patients PLN-101095 was well tolerated with a low discontinuation rate across all dose cohorts IFN-γ biomarker data has potential to serve as response predictor Enrolling FORTIFY,

23. Slide 23: A Phase 1b Trial of PLN-101095

    A Phase 1b Trial of PLN-101095 © 2026 PLIANT THERAPEUTICS

24. Slide 24: Part 2 Dose Expansion and Indication Selection

    Part 2 Dose Expansion and Indication Selection Trial of Acquired Resistance to Prior Immune Checkpoint Blockade STUDY POPULATION • Advanced or metastatic tumors Testing Single PLN-101095 Dose Level • Prior exposure to PD-1 therapy with documented disease progression 1000 mg BID • Secondary resistanc

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