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9524 Background: Cutaneous melanoma is characterized by high TMB, which is associated with increased tumor-specific neoantigen expression (Schumacher Science 2015) and an increased response rate to ICI (Yarchoan NEJM 2019). The TMB in tumors that recur/progress after ICI is not well defined. Lifileucel is a one-time, autologous TIL cell therapy under investigation for treatment of patients (pts) with advanced melanoma. We conducted a matched case-control study of prospectively enrolled pts with advanced melanoma treated with lifileucel in the ICI-naïve (IOV-COM-202 trial, Cohort 1A [C1A]) and post-ICI (C-144-01 trial, Cohort 2 [C2]) setting to investigate the potential association between prior ICI therapy, TMB, and response to lifileucel. Methods: All pts had unresectable or metastatic melanoma. Available cases from C1A (ICI-naïve pts receiving lifileucel + pembrolizumab [pembro]) were matched to controls from C2 (pts receiving lifileucel alone after progression on anti–PD-1/PD-L1 therapy); 3 controls per case were matched at least for BRAF status and disease stage at study entry, and if possible, for anatomic site of tumor harvest. Lifileucel regimen was similar in C1A and C2. In C1A, 1 dose of pembro was given after tumor harvest and before nonmyeloablative lymphodepletion and resumed after lifileucel per standard treatment, for up to 2 y. Objective response rate (ORR) was assessed by investigators per RECIST v1.1. TMB of the resected tumor was measured using the ImmunoID NeXT (C1A) or PGDx elio (C2) platform; a validated conversion factor was used to compare TMB between platforms (Vega Ann Oncol 2021). High TMB was defined as ≥10 mut/MB. Results: Seven pts in C1A and 21 in C2 were included in the case-control study and had ORR of 71.4% and 38.1%, respectively. The percentage of pts with high TMB was 57.1% in C1A and 19.0% in C2 ( P = 0.1). ORR in the low and high TMB groups was 66.7% and 75.0%, respectively, in C1A and 41.1% and 25.0% in C2; 60% of responders in C1A and 12.5% in C2 had high TMB. In logistic regression analysis adjusted for cohort, TMB was not associated with response to lifileucel (odds ratio, 1.0; 95% CI, 0.9–1.1; P = 0.8). Data on tumor mutations and neoantigens, T-cell receptor repertoire, and tumor microenvironment profile will be presented. Conclusions: Our preliminary data indicate that the efficacy (ORR) of lifileucel may be independent of TMB, regardless of treatment setting, consistent with its proposed immune checkpoint pathway-independent mechanism of action. The percentage of patients with high TMB tended to be lower in tumors with prior ICI exposure than in those that were ICI-naïve. Clinical trial information: NCT03645928; NCT02360579.

BackgroundImmune checkpoint inhibitors (ICI) are standard-of-care in the treatment of several types of cancer; however, an unmet medical need exists for early-line combination therapies that are able to provide higher response rates, more durable responses, and manageable long-term safety. Lifileucel (LN-144) and LN-145, adoptive cell therapies using tumor-infiltrating lymphocytes (TIL), have demonstrated encouraging efficacy with acceptable safety in patients with advanced cancer that has failed ICI.1–2 To improve efficacy and safety of early-line treatment options, we explored a combination of TIL and pembrolizumab in patients with ICI-naïve melanoma, head and neck squamous cell carcinoma (HNSCC), and cervical cancer.MethodsIOV-COM-202 (NCT03645928) and C-145-04 (NCT03108495) are ongoing Phase 2 multicenter, multicohort, prospective, open-label studies evaluating TIL cell therapy in ICI-naïve patients with solid tumors. We report efficacy and safety from IOV-COM-202 (Cohort 1A: lifileucel and pembrolizumab in patients with unresectable or metastatic melanoma; Cohort 2A: LN-145 and pembrolizumab in patients with advanced, recurrent, or metastatic HNSCC) and C-145-04 (Cohort 3: LN-145 and pembrolizumab in patients with stage 4b, persistent or recurrent cervical cancer who have not received prior systemic therapy). Eligibility across cohorts included ECOG PS ≤1, ≥1 resectable lesion (diameter ≥1.5 cm post-resection) for TIL manufacturing, and ≥1 measurable lesion for response assessment (by investigator per RECIST v1.1). Lifileucel and LN-145 are cryopreserved TIL infusion products generated at central GMP facilities in a 22-day process. Treatment included tumor resection for TIL manufacturing, followed by 1 dose of pembrolizumab, nonmyeloablative lymphodepletion (cyclophosphamide and fludarabine), TIL infusion, ≤6 interleukin-2 doses (600,000 IU/kg IV), and continued pembrolizumab for ≤24 months.ResultsAs of 09July2021, 32 patients received TIL and pembrolizumab (full-analysis set [FAS]; table 1). Across all cohorts, the objective response rate (ORR) in the FAS was 56.3% (Cohort 1A [melanoma], 87.5%; Cohort 2A [HNSCC], 42.9%; Cohort 3 [cervical], 50.0%; figure 1). Among confirmed responders (n=17), 10 responses (58.8%) were ongoing at data cutoff, with a median study follow-up of 9.7 months. The treatment-emergent adverse-event (TEAE) profile was consistent with the underlying diseases and known profiles of pembrolizumab, nonmyeloablative lymphodepletion, and interleukin-2. The most common (≥30%) Grade ≥3 TEAEs were thrombocytopenia (53.1%), anemia (50.0%), neutropenia (46.9%), and febrile neutropenia (43.8%).ConclusionsThe observed efficacy, including ORR and CR rate, and acceptable safety profile are encouraging and warrant continued investigation of the combination of TIL and pembrolizumab in early-line treatment of patients with advanced cancer. Enrollment is ongoing; updated data will be presented.AcknowledgementsThis study and analysis were funded by Iovance Biotherapeutics, Inc. (San Carlos, CA, USA). Writing support was provided by Amanda Kelly (Iovance); graphics support was provided by Cognition Studio (Seattle, WA, USA).Trial RegistrationNCT03645928 and NCT03108495ReferencesSarnaik AA, et al. J Clin Oncol 2021; doi: 10.1200/JCO.21.00612.Jazaeri AA, et al. J Clin Oncol 2019;37 (suppl; abstract 182).Jimeno A, et al. J Immunother Cancer 2020;8 (suppl; abstract 353).Ethics ApprovalThe IOV-COM-202 study was approved by Advarra Institutional Review Board, approval number Pro00035064; the C-145-04 was approved by WIRB Copernicus Group, approval number 7-1425772-1. All study participants provided written consent via signature of the IRB-approved informed consent form.Abstract 492 Table 1Baseline demographic and clinical characteristics and efficacyAbstract 492 Figure 1Best percentage change from baseline in target lesion sum of diameters for efficacy-evaluable set*

BackgroundA majority of patients with advanced NSCLC develop disease progression with first-line immune-checkpoint inhibitors (ICI) ± chemotherapy. In the setting of ICI resistance, effective strategies to provide deep and durable responses are urgently needed. Lifileucel (LN-144) and LN-145 are centrally manufactured (cryopreserved drug-product, 22-day manufacturing process) autologous TIL products that have demonstrated activity in advanced melanoma, cervical cancer, and head and neck carcinoma.1–4 Here, we report the first safety and efficacy data for LN-145 as monotherapy in patients with advanced NSCLC.MethodsIOV-COM-202 (NCT03645928) is a phase 2 multicenter, multicohort, open-label study evaluating autologous TIL cell therapy in patients with solid tumors. We report data from Cohort 3B, investigating LN-145 monotherapy in patients with advanced or metastatic NSCLC. Eligibility required 1–3 prior lines of systemic therapy, including either ICI or oncogene-directed therapy. Treatment included nonmyeloablative lymphodepletion, TIL infusion, and ≤6 interleukin-2 doses. Primary endpoints were safety (incidence of Grade ≥3 treatment-emergent adverse events [TEAEs]) and objective response rate (ORR, investigator-assessed using RECIST v1.1). Exploratory biomarker analyses, including T-cell receptor (TCR) repertoire, were performed.ResultsAs of 24June2021, 28 patients received LN-145 (full-analysis set [FAS]; table 1) and 24 were efficacy-evaluable; all had received prior ICI. TIL were most commonly harvested from lung metastases (57.1%). Safety was consistent with the underlying disease and known TEAE profiles of nonmyeloablative lymphodepletion and interleukin-2. Grade ≥3 TEAEs in ≥30% of patients were thrombocytopenia and anemia. The ORR in the FAS and efficacy-evaluable set was 21.4% (6/28) and 25.0% (6/24; figure 1), respectively. Median duration of response was not reached and 83% (5/6) of responses were ongoing at last follow-up (median study follow-up, 8.2 months). One patient had a complete metabolic response, ongoing at 20.7 months; 2 responses occurred in patients who were PD-L1–negative. All responders received ≥2 prior lines of systemic therapy. Twenty-six patients had TIL available from the final drug-product for TCR repertoire analysis; mean (min-max) number of unique TCR clones was 13,142 (3093–35,734) and Shannon Entropy index was 7.34 (3.7–12). Updated data will be presented.Abstract 458 Figure 1Best percentage change from baseline in target lesion sum of diameters for efficacy-evaluable setAbstract 458 Table 1Baseline patient demographic and clinical characteristics; efficacy parametersConclusionsLN-145 was successfully manufactured and one-time treatment produced an expected safety profile and durable responses in heavily pretreated patients with NSCLC, regardless of PD-L1 expression. The activity of LN-145 monotherapy is encouraging and warrants further investigation of LN-145 as a single-agent and in combination in patients with NSCLC in ongoing studies IOV-LUN-202 (NCT04614103) and IOV-COM-202 Cohorts 3A and 3C (3B closed to enrollment).AcknowledgementsThis study and analysis were funded by Iovance Biotherapeutics, Inc. (San Carlos, CA, USA). Writing support was provided by Amanda Kelly (Iovance); graphics support was provided by Cognition Studio (Seattle, WA, USA).Trial RegistrationNCT03645928ReferencesSarnaik AA, et al. J Clin Oncol 2021; doi: 10.1200/JCO.21.00612.. Thomas SS, et al. J Clin Oncol 2021;39: (suppl; abstract 9537).Jazaeri A, et al. J Clin Oncol 2019;37: (suppl; abstract 2538).Jimeno A, et al. J Immunother Cancer 2020;8: (suppl; abstract A378).Ethics ApprovalThe study was approved by Advarra Institutional Review Board, approval number Pro00035064 and all study participants provided written consent via signature of the IRB-approved Informed Consent form.

Background Single agent checkpoint inhibitors (CPI) are an approved first or second-line therapy in head and neck squamous cell carcinoma (HNSCC), but their efficacy is limited. Adoptive cell therapy with tumor infiltrating lymphocytes (TIL, LN-145) has demonstrated efficacy in multiple malignancies alone or in combination with CPI. To improve HNSCC therapy, a combination of pembrolizumab and LN-145 was explored. Methods IOV-COM-202 is an ongoing Phase 2 multicenter, multi-cohort, open-label study evaluating LN-145 in multiple settings and indications, and here we report cohort 2A which enrolled CPI naive HNSCC patients who received the combination of LN-145 and pembrolizumab. Key eligibility criteria include up to 3 lines of prior therapy, ECOG Results Nine (N=9) HNSCC patients have received LN-145 plus pembrolizumab, with a median duration of follow up of 6.9 months. Nine and 8 patients were evaluable for safety and efficacy, respectively. Mean number of prior therapies was 1.1 with 89% of the patients having received prior chemotherapy. Four were HPV+, 2 HPV-, 3 unknown. The Treatment Emergent Adverse Event (TEAE) profile was consistent with the underlying advanced disease and the known AE profiles of pembrolizumab, the lymphodepletion and IL-2 regimens. The most common TEAE were chills, hypotension, anemia, thrombocytopenia, pyrexia, fatigue and tachycardia. Four patients had a confirmed, objective response with an ORR of 44% (1 CR, 3 PR, 4 SD, 1 NE) per RECIST 1.1. The disease control rate at data cutoff was 89% in 9 patients, and 7 of the 8 evaluable patients (87.5%) had a reduction in target lesions. Median DOR was not reached. Conclusions LN-145 can be safely combined with pembrolizumab in patients with metastatic HNSCC. LN-145 plus pembrolizumab shows early signs of improved efficacy particularly when compared with literature reports of pembrolizumab alone in a comparable patient population. Enrollment is ongoing and updated data will be presented. Trial Registration NCT03645928 Ethics Approval The study was approved by Advarra Institutional Review Board, under protocol number: Pro00035064.

Background TIL (especially CD8+ T cells) in the tumor microenvironment is associated with survival outcomes in many solid tumors, including melanoma (Mel), head and neck squamous cell carcinoma (HNSCC), and non-small cell lung cancer (NSCLC). Lifileucel (LN-144), has shown efficacy with durable responses in advanced melanoma (Mel) (Sarnaik et al., ASCO 2020), metastatic cervical cancer (Jazaeri et al., ASCO 2019), and LN-145 + pembrolizumab in HNSCC (Jimeno et al., SITC 2020). TIL therapy has shown evidence of efficacy in metastatic NSCLC in a Phase 1 study (Creelan et al., ASCO 2020). Methods IOV-COM-202 (NCT03645928) is a Phase 2 global, open-label multi-cohort, non-randomized study designed to evaluate the safety and efficacy of TIL therapy as a single agent or in combination with immune checkpoint inhibitors. All patients receive either, lifileucel, LN-145 or LN-145-S1 (PD-1 select TIL), which is manufactured at centralized GMP facilities generating a cryopreserved infusion product which is shipped to the treatment centers. Cohort 1, 2 and 3 enroll Mel, HNSCC and NSCLC patients, respectively (Table 1). Patients undergo a nonmyeloablative lymphodepletion (NMA-LD) regimen prior to TIL infusion, followed by up to 6 doses of intravenous IL-2. Patients in Cohorts 1A, 2A, and 3A start pembrolizumab following tumor harvest for TIL generation, but prior to NMA-LD. Pembrolizumab is dosed per label. Patients in Cohorts 1B, IC and 3B receive LN-145-S1, lifileucel, and LN-145, respectively. Cohort 3C patients receive a dose of ipilimumab and nivolumab prior to tumor harvest, with nivolumab continuing Q4W for up to 2 years, or until progression or unacceptable toxicity. Key eligibility includes: ≥ 18 years of age; RECIST measurable disease; ≥ 1 lesion(s) available for TIL generation; ECOG PS 0-1. The primary endpoint: ORR per RECIST v1.1. Secondary endpoints: safety, CR rate, DOR, DCR, PFS, and OS. Table 1.IOV-COM-202 Study DesignCohortTIL ManufacturingCohort 1A: Melanoma PD-1/ PD-L1 Naïve LN-144 + Pembrolizumab N=12LN-144: 22-day manufacturingCohort 1B: Melanoma ≥1 prior systemic therapies LN-145-S1 N up to 27LN-145-S1: PD-1 selected TILCohort 1C: Melanoma ≥1 prior systemic therapies LN-144 Gen 3 N up to 27LN-144 Gen 3: 16-day manufacturingCohort 2A: Head and Neck PD-1/ PD-L1 Naïve LN-145 + Pembrolizumab N=19LN-145: 22-day manufacturingCohort 3A: NSCLC PD-1/ PD-L1 Naïve LN-145 + Pembrolizumab N=12LN-145: 22-day manufacturingCohort 3B: NSCLC ≥1 prior systemic therapies LN-145 N=12LN-145: 22-day manufacturingCohort 3C: NSCLC 1 prior systemic therapy TIL + Ipilimumab / Nivolumab N up to 26 Citation Format: Scott Gettinger, Harriet Kluger, Adam Schoenfeld, Allison Betof-Warner, Kai He, Ammar Sukari, Bernard Doger de Speville Uribe, Sylvia Lee, Simon Haefliger, Zelanna Goldberg, Alex Cacovean, Rana Fiaz, Guang Chen, Madan Jagasia, Friedrich Graf Finckenstein, Maria Fardis, Antonio Jimeno. A Phase 2, multicenter study of autologous tumor infiltrating lymphocytes (TIL, LN 144/LN-145/LN-145-S1) in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT235.

Background While Bruton's Tyrosine Kinase (BTK) inhibitors approved for CLL/SLL (ibrutinib, acalabrutinib) can mediate durable responses in some patients, relapses are seen primarily as a result of acquired mutations in BTK enzyme and/or phospholipase C gamma 2. Adoptive cell transfer of IOV-2001, a polyclonal and nongenetically modified autologous T-cell infusion product, is being investigated as a therapy option for CLL/SLL patients who are progressing or have progressed on ibrutinib or acalabrutinib. Methods IOV-CLL-01 (NCT04155710) is a First in Patient, Phase 1/2, open-label, multi-cohort, dose-finding study designed to evaluate the safety and efficacy of IOV-2001, in patients with CLL/SLL (Table 1). 50 ml of blood obtained from patients is used to generate Peripheral Blood Lymphocytes (PBLs). PBLs are result of expansion of T-cells in a 9-day manufacturing process at a centralized GMP facility. The product is then cryopreserved and sent back to the treatment center for infusion to the patient. IOV-2001 is a one-time administration cell therapy which involves a preparative regimen of lymphodepleting chemotherapy consisting of cyclophosphamide IV 500 mg/m2 and fludarabine IV 30 mg/m2 for 3 days followed by 2 days of rest. IOV-2001 is administered as a single infusion, followed by up to 6 doses of IL-2. Key eligibility includes diagnosed CLL/SLL patients (18 to 70 years of age) with radiographically measurable disease; and ECOG PS of 0-1, along with specifics per Table 1. The primary objective for Phase 1 is to determine the RP2D, and for Phase 2 is to evaluate the Investigator-assessed efficacy of IOV-2001 at RP2D followed by IL-2. Table 1.Overview of IOV-CLL-2001PhaseStudy PopulationCohort Test Product, Dose Regimen, and Route of AdministrationPhase 1CLL / SLL that has relapsed or is relapsing on ibrutinib or acalabrutinibDose-finding with IOV-2001 dose de-escalation guided by DLT observations:-Cohort 1a: IOV-2001, followed by ≤6 doses of SC low-dose IL-2 (9 MIU) every 8-12 hours-Cohort 1b: IOV-2001, followed by ≤6 doses of IV high-dose (600,000 IU/kg) every 8-12 hoursPhase 2IOV-2001 RP2D dose, followed by ≤6 doses of the selected IL-2 dose:-Cohort 2: with del(17p) and/or TP53 mutation-Cohort 3: without del(17p) and/or TP53 mutation Citation Format: Meixiao Long, Jennifer Woyach, Javier Pinilla-Ibarz, Deborah M. Stephens, Alex Cacovean, Rana Fiaz, Zelanna Goldberg, Madan Jagasia, Friedrich Graf Finckenstein, Maria Fardis, John C. Byrd. A Phase 1/2 study evaluating the safety and efficacy of IOV-2001 in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT244.

9537 Background: Tumor infiltrating lymphocyte (TIL) cell therapy has demonstrated safety and efficacy in advanced melanoma, both in the pre-immune checkpoint inhibitor (ICI) setting (Goff, JCO 2016) and in patients who have failed anti-PD-1/PD-L1 therapy (Sarnaik, 2020). Combination of TIL and pembrolizumab (pembro) in ICI-naïve patients has demonstrated encouraging efficacy data with acceptable safety in head and neck squamous cell carcinoma (Jimeno, 2020). To improve treatment options in early lines, we explore a combination of LN-144 and pembro in patients with ICI-naïve advanced melanoma. Methods: IOV-COM-202 is a Phase 2 multicenter, multi-cohort, open-label study evaluating TIL cell therapy in multiple settings and indications. We report on Cohort 1A enrolling ICI-naïve advanced melanoma (unresectable or metastatic) patients for treatment with a combination of LN-144 and pembro. Key eligibility criteria include ≤ 3 lines of prior therapy, ECOG < 2, one resectable lesion for lifileucel manufacturing, and ≥ 1 measurable lesion for response assessment. Primary endpoints are objective response rate (ORR) per RECIST 1.1 and safety as measured by incidence of Grade ≥3 treatment-emergent adverse events (TEAE). LN-144 is generated at centralized GMP facilities in a 22-day process. A nonmyeloablative lymphodepletion (NMA-LD) using cyclophosphamide and fludarabine is administered preceding a single LN-144 infusion, followed by < 6 doses of IL-2 (600,000 IU/kg). Pembro is administered after tumor harvest but prior to NMA-LD and continues after lifileucel per label. Results: Seven patients have received lifileucel in combination with pembro as of data extraction date (Feb 14, 2021). Five of the 7 treated patients were treatment-naïve, 1 patient had prior BRAFi + MEKi and 1 had received prior chemotherapy; 71% had liver/brain lesions, 43% had LDH > ULN. Mean SOD for the target lesions was 111 mm, with 86% of patients with > 3 target lesions, representing advanced disease at baseline for this patient group. The TEAE profile was consistent with the underlying disease and known AE profiles of pembro, NMA-LD and IL-2. Six patients had a confirmed objective response with an ORR of 86% (1 CR, 5 PR) and 1 best response of SD. Three of the responding patients have remained off pembro due to pembro related AEs for 3, 4 and 13 months (mos), yet maintaining response. All responding patients remain in response with the longest duration of response being 16.8 mos. Conclusions: Lifileucel can be safely combined with pembro in patients with ICI-naïve advanced melanoma. The ORR of 86% is encouraging when compared to pembro alone in a similar patient population, especially considering the disease burden at baseline and persistence of responses in patients off therapy. Enrollment is ongoing and updated data to be presented. Clinical trial information: NCT03645928.

Objective To investigate whether anterior choroidal artery (AChA) territory sparing or AChA infarction restricted to the medial temporal lobe (MT), implying good collateral status, predicts good outcome, defined as modified Rankin Scale 0–2, at discharge in acute internal carotid artery (ICA) occlusion. Methods The authors studied consecutive patients with acute ICA occlusion admitted to an academic medical centre between January 2002 and August 2010, who underwent MRI followed by conventional angiography. The pattern of AChA involvement on initial diffusion-weighted imaging was dichotomised as spared or MT only versus other partial or full. The association of AChA infarct patterns and good outcome at discharge was calculated by multivariate logistic regression with adjustment. Results For the 60 patients meeting entry criteria, mean age was 68.3 years and median admission NIH Stroke Scale score was 19. AChA territory was spared or restricted to the MT in 27 patients and other partially involved or fully involved in 33 patients. AChA territory spared or ischaemia restricted to MT only, compared with other partial infarct patterns or full infarct, was independently associated with good discharge outcome (44.4% vs 12.1%, OR 7.24, 95% CI 1.32 to 39.89, p=0.023). Conclusion In acute ICA occlusion, the absence of AChA infarction or restriction to the MT is an independent predictor of good discharge outcome. Analysis of AChA infarct patterns may improve early prognostication and decision-making.

Background and Purpose— The purpose of this study was to evaluate the potential clinical value of arterial spin-labeled (ASL) perfusion MRI in acute ischemic stroke (AIS) through comparison with dynamic susceptibility contrast (DSC) enhanced perfusion MRI. Methods— Pseudocontinuous ASL with 3-dimensional background-suppressed gradient and spin echo readout was applied with DSC perfusion MRI on 26 patients with AIS. ASL cerebral blood flow and multiparametric DSC perfusion maps were rated for image quality and lesion severity/conspicuity. Mean ASL cerebral blood flow and DSC perfusion values were obtained in main vascular territories. Kendall coefficient of concordance was calculated to evaluate the reliability of ratings. Spearman correlation coefficients were calculated to compare ratings and quantitative perfusion values between ASL and DSC perfusion maps. Results— ASL cerebral blood flow and DSC perfusion maps provided largely consistent results in delineating hypoperfused brain regions in AIS. Hyperemic lesions, which also appeared frequently in the AIS cases studied, were more conspicuous on ASL cerebral blood flow than on DSC cerebral blood flow, mean transit time and time to the maximum of the tissue residual function maps. Conclusions— As a rapid, noninvasive, and quantitative technique, ASL has clinical use in detecting blood flow abnormalities in patients with AIS.

Background: Availability of 4G cellular network and video cellphone handsets may allow mobile videophone assessment to be employed in prehospital stroke care. The California Brief Stroke Scale (CABSS) is a 4 item scale designed as a mobile videophone test to evaluate a prehospital telemedicine instrument to rate stroke severity. Potential uses include identifying patients who are likely harboring persisting large vessel occlusions and to characterize baseline deficits prior to enrollment in prehospital trials. Methods: One bedside and one remote CABSS score were independently obtained on 15 ischemic stroke patients with persistent neurologic deficits. The bedside examination was performed by a stroke neurologist. The remote examination was performed by a second stroke neurologist through mobile video phone. A CABSS score of 1 or higher (scale 0-7) was an index of global stroke deficit severity. Kappa coefficients were calculated for concordance between bedside and remote scores. Results: The median National Institutes of Health Stroke Scale score was 6 (interquartile range IQR 4-10). On average the CABSS score evaluation took 25 seconds to perform. The median video CABSS was 2, (IQR1-3) and median bedside CABSS was 3, (IQR 1-3). Based on weighted K coefficients, cortical findings (aphasia, gaze deviation/hemineglect) displayed excellent agreement κ=1 (95% CI 1.0) and non-cortical findings (facial droop, arm drift) displayed substantial agreement κ =0.7 (95% CI 0.4-1.0). There was substantial agreement between bedside and remote methods for the total CABSS κ 0.68 (95% CI 0.44-0.92). The CABSS scores obtained by bedside and remote methods were strongly correlated (r= 0.85, P Conclusion: Our prospective study found that mobile videocell phone evaluation using CABSS is a feasible and reliable means of examining hyperacute stroke patients in the field. A physician can rapidly perform an audiovideo examination to increase the accuracy of prehospital identification of patients harboring persisting large vessel occlusions and characterize baseline deficits prior to enrollment in prehospital clinical trials to a clinically important degree.