Third party administrators often cite overutilization and cost as justifications for restrictive proton beam therapy (PBT) coverage policies. We collaborated with a state-wide self-funded employer, The University of Texas System (UTS), to implement a PBT coverage pilot ensuring appropriate access to care without increasing cost. This pilot conducts a value-based assessment of PBT through evaluation of utilization trends and comprehensive charge analysis of medical claims. UTS adopted our institution’s evidence-based treatment guidelines and inclusion criteria which expanded PBT coverage by 5 additional body sites: head and neck (HN), esophagus, breast, thoracic, and prostate (GU). Coverage also included patients on 1 of any 6 NCI/NIH randomized controlled trials. The pilot obtained IRB approval, with all patients enrolled on a prospective research trial. The majority of patients with UTS benefits treated with PBT during this time were approved via the pilot. Patient satisfaction (PROs), safety (grade 4-5 complications), treatment related toxicities, and total billed charges (cost of care) were pilot metrics. The primary endpoint was cost of care, including all claims 1 month pre-treatment, through the PBT course, up to 6 months post-treatment. PBT claims were compared with case-matched (by employer, site, indication, and stage) photon patients who were treated within the same enrollment period. Enrollment initiated April 2016, accruing 32 patients over 3 years, vs. predicted utilization of 120 patients (p<.01). The average pilot prior authorization time was <1 business day, vs. the historical pre-pilot average of 17 business days. Of the 32 pilot patients, 22 (9 HN, 8 GU, 3 breast, 2 thoracic) were treated with PBT with a median follow-up of 20.1 months. There were no Grade 4-5 toxicities. During this timeframe, 25 patients who met pilot eligibility were instead treated with photons. Out of these, 17 were case-matched to 17 PBT pilot patients with ≥6 month follow-up. Median number of fractions was 30 for both groups (p=.96). On analysis, employer costs with PBT were dramatically lower than estimated (initially expecting an increase for PBT), with average billed charges actually 4.4% lower for PBT (p=.84). Percentage of RT charges to total charges was 77% vs. 64% for PBT and photons (p=.09), respectively, with higher ancillary care utilization by the latter. This state-wide insurance coverage pilot demonstrates that appropriate access to PBT does not result in overutilization or increased employer cost. Objective evidence-based treatment guidelines and policies can ensure appropriate patient selection while reducing administrative burden. Collaboration among employers, payers, and providers can improve access to PBT without increasing cost.