THE NEXT-GENERATION PAN-RAF INHIBITOR, KIN-2787, IS ACTIVE IN CLASS II AND CLASS III BRAF MUTANT MODELS Aleksandra Franovic, Nichol Miller, Paul Severson, Toufike Kanouni, Noel Timple, Ping Jiang, Eric Murphy, Eric S. Martin Kinnate Biopharma Inc., San Diego, CA JUNE 2021 2 KIN-2787 is a potent and selective pan-RAF inhibitor NTRK 3 EPHB2 FG FR1 NTRK 2 FG FR4 NTRK 1 KDR FLT1 CSF 1 R EPHB1 RO R2 EPHA5 KI T M USK RO R1 RET EPHB3 DDR2 M ERTK EPHA3 AXL FLT4 DDR1 TYRO 3 PDG FRA EPHA4 FLT3 I NSRR PDG FRB IG F1 R EPHA6 ERBB 2 I NSR EG FR YES1 M ET EPHB4 M ST 1 R M AP 3 K 11 SRC RO S 1 M AP 3 K 9 ALK TEK EPHA7 LYN TI E1 LTK ERBB 4 RYK HCK FYN M AP 3 K 21 EPHA8 PTK7 M AP 3 K 10 TNK1 TYK2 TNK2 J AK1 LCK FG R J AK2 ERBB 3 J AK3 EPHA2 BLK RI PK 4 ANKK 1 M AP 3 K 12 ZAP 70 PTK2 B SYK M AP 3 K 13 AATK EPHA1 PTK2 LM TK2 ACVR 1 B RAF 1 I TK TG FBR1 M AP 3 K 20 FRK TEC BRAF EPHB6 KSR1 RI PK 2 KSR2 SRM S TXK PTK6 I RAK 1 LM TK3 ACVR 1 C BTK I RAK 3 LI M K1 ARAF LI M K2 BM PR 1 B BM X EPHA10 TESK1 BM PR 1 A I LK M ATK M AP 3 K 7 TESK2 ACVRL 1 RI PK 3 CSK TNNI 3 K ACVR 1 ABL 2 ACVR 2 A FES I RAK 2 ABL 1 ACVR 2 B RI PK 1 FER TG FBR2 J AK3 • Oncogenic BRAF alterations are observed in ~6% of human M AP 3 K 2 AM HR 2 J AK2 LRRK 1 M AP 3 K 3 LRRK 2 BM PR 2 TYK2 M AP 3 K 5 STYK1 I RAK 4 M AP 3 K 19 NPR1 J AK1 M AP 3 K 15 NPR2 M AP 4 K 5 STK25 MOS STK4 STK3 M AP 4 K 1 M AP 4 K 3 G UCY 2 C STK24 DSTYK W NK1 M AP 3 K 6 M AP 4 K 2 STK26 DYRK 2 W NK3 PBK DYRK 3 M AP 3 K 4 G UCY 2 D W NK2 NRBP 2 M AP 4 K 4 DYRK 1 A NRBP 1 DYRK 4 O XSR1 G UCY 2 F M I NK 1 DYRK 1 B M AP 3 K 1 STK39 TNI K W NK4 NRK M LKL STRADA M YO 3 A EI F 2 AK3 STRADB TEX14 SLK M YO 3 B EI F 2 AK2 HI PK 3 TEX14 STK10 HI PK 1 EI F 2 AK4 cancers and lead to aberrantly activated BRAF monomers TAO K 1 SCYL 3 M AP 3 K 8 TAO K 2 HI PK 2 SCYL 1 M AP 3 K 14 TAO K 3 SCYL 2 PRPF 4 B PAK1 CLK4 EI F 2 AK1 HI PK 4 PAK3 PAK4 STK35 PAK2 CLK1 ERN1 PAK7 CLK2 M AP 2 K 5 PDI K 1 L ERN2 TBCK PAK6 CLK3 M AP 2 K 7 M AP 2 K 1 RNASEL EI F 2 AK4 M AP 2 K 2 TTK STKLD1 SRPK3 UHM K 1 M AP 2 K 3 SRPK2 PKM YT 1 M AP 2 K 4 M AP 2 K 6 SRPK1 CSNK 2 A 1 W EE1 CSNK 1 D M AK PO M K CSNK 2 A 2 CDC7 W EE2 TTBK1 TP53RK I CK CSNK 1 E G SK3 B G SG 2 TTBK2 G SK3 A MOK CSNK 1 A 1 CDKL 3 CSNK 1 A 1 L PI NK 1 PEAK1 CDKL 2 PKDCC VRK3 (Class I), homodimers (Class II) & heterodimers (Class III) CSNK 1 G 2 CDKL 5 M APK 15 CDKL 1 STK31 PRAG 1 CSNK 1 G 1 CDKL 4 M APK 4 PXK SBK3 M APK 6 CSNK 1 G 3 NLK PI K3 R 4 BUB1 SBK2 M APK 7 SBK1 BUB1 B CHUK VRK1 M APK 3 I KBKB PLK4 CDK7 VRK2 I KBKE M APK 1 TBK1 M APK 12 STK16 CDK11B M APK 8 TLK2 M APK 13 M APK 9 G AK PLK3 M APK 10 CDK10 AAK1 TLK1 ULK3 M APK 11 CAM KK 1 CDK8 PLK1 PLK2 CDK19 M APK 14 CDK4 CDK20 ADRBK 1 BM P 2 K CAM KK 2 G RK1 CDK6 ULK1 ADRBK 2 STK36 G RK5 G RK7 CDK15 ULK2 ULK4 G RK6 G RK4 CDK14 CDK9 NEK6 RPS 6 KC1 NEK7 NEK10 CDK17 PASK NEK8 STK40 PDPK1 RPS 6 KA1 RPS 6 KA5 RPS 6 KL 1 NEK9 STK11 RPS 6 KA4 CDK18 CDK12 RPS 6 KA3 CDK5 CDK13 CDK16 RPS 6 KA6 NEK2 CHEK 1 RPS 6 KA2 RPS 6 KB1 AKT 2 AKT 1 NEK11 AURKA RPS 6 KB2 AKT 3 CDK1 NEK4 CDK3 SG K1 AURKB CDK2 PKN1 TRI B 3 PI M 1 SG K2 SG K3 PI M 2 AURKC LATS1 PRKG 2 NEK3 PKN2 PI M 3 LATS2 PRKG 1 TRI B 2 PKN3 STK38 NEK5 O BSCN PRKY STK38L TRI B 1 STK32A PRKX SPEG PRKCH NEK1 M AST 3 O BSCN M ASTL PRKCE PRKCZ STK33 STK32B PRKCI PRKCD SPEG STK32C PRKCQ PRKACG PRKCG PRKACA TTN M AST 2 PRKACB TRI O • Approved BRAF inhibitors benefit patients with Class I BRAF M YLK KALRN RO CK 1 PRKCA CHEK 2 TSSK4 HUNK RO CK 2 > 90% inhibition PRKCB M YLK2 SNRK DM PK M AST 4 M AST 1 TSSK6 CI T STK17B NI M 1 K PRKD 2 TSSK3 STK17A DCLK 3 DCLK 1 CDC42BPG M YLK4 TSSK1 B DCLK 2 PRKD 1 TSSK2 M YLK3 M ELK PRKD 3 CASK DAPK 3 CDC42BPB DAPK 2 CAM KV PHKG 1 DAPK 1 M APKAPK 5 CDC42BPA PSKH1 M KNK 1 PHKG 2 PRKAA 2 PSKH2 M KNK 2 M APKAPK 2 CAM K 2 G PRKAA 1 CAM K 2 A CAM K 2 B CAM K 2 D > 75% inhibition BRSK 2 M APKAPK 3 CAM K 4 mutation-driven cancers (i.e., BRAF V600) but are not BRSK 1 RPS 6 KA6 NUAK 2 RPS 6 KA1 NUAK 1 RPS 6 KA5 RPS 6 KA4 PNCK SI K3 RPS 6 KA3 RPS 6 KA2 CAM K 1 G SI K1 SI K2 CAM K 1 CAM K 1 D > 50% inhibition M ARK 4 M ARK 3 M ARK 1 effective in patients with Class II or III BRAF alterations M ARK 2 Biochemical Assay KIN-2787 IC50 (nM) • KIN-2787 is an orally-available, potent and selective small ARAF 2.41 molecule pan-RAF inhibitor that inhibits Class II & III dimers, BRAF 3.46 in addition to Class I BRAF mutants BRAFV600E 1.53 RAF1 0.573 Kinase selectivity for KIN-2787 at 1000 nM across 653 kinases was established in single dose, duplicate measurements in a radiometric kinase • The activity of KIN-2787 was assessed in vitro and in vivo in assay (Reaction Biology Corp.). Percent inhibition is relative to DMSO control. IC50 values for RAF family kinases and selected off-targets were determined various BRAF-driven cancer models using a 4-parameter fit model from a 10-point dose response curve performed with 3 replicates at each drug concentration. Aleksandra Franovic, Ph.D. Director, Translational Medicine | Kinnate Biopharma Inc. 3 Single agent activity of KIN-2787 in BRAF-mutant cell lines pERK EC50 (nM) Tumor Cell Line Lineage BRAF Status MAPK Pathway Alteration(s) Binimetinib KIN-2787 A-375 Melanoma BRAFV600E 8 67 Class I Colo800 Melanoma BRAFV600E 5 112 BxPC-3 Pancreatic BRAFindel(VTAPTP) 3 51 OV-90 Ovarian Class II BRAFindel(NVTAP) 4 26 NCI-H2405 NSCLC BRAFindel(LNVTAP) 6 10 WM3629 Melanoma BRAFD594G, NRASG12D 5 9 Class III CAL-12T NSCLC BRAFG466V 3 18 MIA PaCa-2 Pancreatic KRASG12C 3 685 NCI-H358 NSCLC Wild type KRASG12C 1 351 CHL-1 NSCLC Wild type 5 580 For the evaluation of cellular potency, cells were treated with the indicated compounds for 1 hour and ERK phosphorylation (pERK) was measured in cell lysates using a homogenous time-resolved fluorescence assay. The compounds were run in 10-point, 3-fold serial dilutions starting at 10,000 nM to establish EC50 values using a 4-parameter fit model. All samples were run in triplicate and represent an average of 2 or more independent experiments. Aleksandra Franovic, Ph.D. Director, Translational Medicine | Kinnate Biopharma Inc. 4 KIN-2787 is efficacious in Class II and Class III BRAF-mutant human xenograft models BxPC3 Class II BRAF-mutant Pancreatic Cancer WM3629 Class III BRAF-mutant Melanoma TGI 109% TGI 101% TGI 118% TGI 101% 30% 30% Aleksandra Franovic, Ph.D. Director, Translational Medicine | Kinnate Biopharma Inc. 5 KIN-2787 suppresses MAPK pathway expression in vivo WM3629 Class III BRAF-mutant Melanoma – 3-day PK/PD Analysis Time- and exposure-dependent PD Reduction in MAPK target gene Reduction in pMEK and MAPK biomarker (pERK) inhibition RNA expression target gene protein levels 10 mg/kg 20 mg/kg Vehicle BID QD pMEK GAPDH 1 h MEK GAPDH EphA2 GAPDH 7 h DUSP6 GAPDH Time (Hours) Time (Hours) 1Wagle (Huang) et al. 2018 NPJ Precis. Oncol. Aleksandra Franovic, Ph.D. Director, Translational Medicine | Kinnate Biopharma Inc. 6 Conclusions • KIN-2787 has pronounced in vitro and in vivo activity against human cancers driven by Class I, Class II and Class III BRAF mutations • Time- and exposure-dependent inhibition of MEK-ERK phosphorylation was achieved and accompanied by suppression of MAPK transcriptional targets at the RNA and protein level • Twice daily (BID) dosing was well-tolerated, led to prolonged target coverage / inhibition and a trend towards more frequent and deeper tumor responses in vivo • A phase 1 dose escalation and expansion clinical trial evaluating the pharmacokinetics, safety and efficacy of KIN-2787 monotherapy in patients with advanced or metastatic solid tumors with BRAF gene alterations is expected to initiate in 2021 Aleksandra Franovic, Ph.D.