S48 Poster abstracts of the 18th Annual BTOG / Lung Cancer 139S1 (2020) S1–S102 (n=385), 188 (48.8%) received chemotherapy, 123 (31.9%) received IO therapy, and 74 (19.2%) received TT. For the subgroup who initiated 1L chemotherapy or IO therapy, chemotherapy was the most commonly used 2L treatment, whereas most patients receiving TT in 1L (89.2%) continued TT in 2L (Table 1). Conclusion: As a percentage of total 1L treatment, IO therapy usage has increased in recent years. However, the majority of the patients with aNSCLC were treated with 1L chemotherapy regimens. Among patients who received 2L treatment, most received chemotherapy or IO therapy. Future analyses should focus on evaluating clinical outcomes in patients with aNSCLC by choice of 1L treatment and treatment sequencing. Disclosure: J. Lester: honoraria, sponsorship, advisory board participation from Roche, AstraZeneca, Pfizer, Boehringer- Ingelheim, MSD, BMS, and Lilly; S. Khan and J. Brock: no relevant conflict of interest to declare; C. Powell: received sponsorship to conferences from Boehringer-Ingelheim and Roche and honoraria for talks/session chairing from Boehringer-Ingelheim and Bristol- Myers-Squibb (but not within the last 12 months); C. Escriu: travel grants from MSD, Roche, AstraZeneca and Boehringer-Ingelheim, consultancy fees from MSD, AstraZeneca and Boehringer-Ingelheim, lecturer fees from Pfizer, AstraZeneca and Roche; E. Hudson: Advisory Board work for Roche and Tesaro; A. Conn: educational grants from Lilly, AstraZeneca, Boehringer-Ingelheim; T. Mansy: honorarium and congress travel funding from: MSD, Bristol- Myers-Squibb, PharmaMar, AstraZeneca, Roche, Tesaro, Amgen; S. Chan: honoraria for presentation from Bristol-Myers-Squibb; X. Zhuo: employee of Merck KgaA employee when the analysis was conducted; A. Durand: employee of Merck Serono Limited; X. Zhang and V. Pawar: employee of EMD Serono Inc. 110 An audit of thyroid dysfunction evaluation in patients in with non-small cell lung cancer, treated with immune checkpoint inhibition D. McMahon 1 , C. Buckley 1 , G. Watson 2 , A. Hogan 2 , S. Blazkova 3 1 Mater Misericordiae University Hospital, Dublin, Ireland, 2 Galway University Hospital, Galway, Ireland, 3 University Hospital Galway, Galway, Ireland Introduction: Immunotherapy has revolutionized the management of Non-Small Cell Lung Cancer (NSCLC), however, it is increasingly recognized that it can be associated with unique toxicities. Thyroid dysfunction is one of the most common adverse effects and monitoring of thyroid function tests (TFTs) is recommended prior to and during immune checkpoint inhibition (ICI). We aimed to audit our compliance with European Society for Medical Oncology (ESMO) recommendation for TFTs monitoring of those treated with ICI. Methods: We identified a group of 50 patients with NSCLC who were treated with ICI in a single cancer centre in Ireland between 2015 and 2018. A total of 21 patients received nivolumab, 20 pembrolizumab, 7 durvalumab and 2 received atezolizumab. We retrospectively reviewed laboratory results of these patients and recorded whether TFTs were checked on day 1 of treatment and in compliance with guidelines on subsequent cycles. ESMO recommendations for anti- PD-1 and PDL-1 ICI for were used as comparison standard. Results: A total of 35 patients (70%) did not have their TFTs monitored in compliance with ESMO guidelines during treatment. 14 patients (28%) had their TFTs checked prior to initiation of treatment, with 36 (72%) not having TFTs on initiation of ICI therapy. 43 patients (86%) had recorded at least one non-compliance, either at the start of ICI therapy or during treatment. A total of 11 patients (22%) developed immune-related thyroid dysfunction, with 8 developing hypothyroidism and 3 developing hyperthyroidism. Conclusion: The surveillance of thyroid function while on ICI therapy, both before and during treatment, was inconsistent and not in line with ESMO recommended standards. A quality improvement project involving education of clinical staff was carried out, with a formal re-audit planned. Disclosure: All authors have declared no conflicts of interest. 111 The use of atezolizumab combination therapy in the EGFR + metastatic non-squamous NSCLC setting: practical guidance based on early clinical experience T. Geldart 1 , P. Belitei 2 , T. Benepal 3 , A. Mehta 4 , S. Baijal 5 , A. Denton 6 , C. Escriu 7 , M. Chitnis 8 , M. Bennett 9 , S. Popat 10 1 Royal Bournemouth and Christchurch Hospitals National Health Service Trust, Bournemouth, United Kingdom, 2 New Cross Hospital, Wolverhampton, United Kingdom, 3 St George’s Hospital NHS Trust, London, United Kingdom, 4 Royal Surrey Hospital, Guildford, United Kingdom, 5 Heartlands Hospital, Birmingham, United Kingdom, 6 Mount Vernon Cancer Centre and London North West University Healthcare NHS Trust, Northwood, United Kingdom, 7 The Clatterbridge Cancer Centre, Birkenhead, United Kingdom, 8 Oxford University Hospitals, Oxford, United Kingdom, 9 Roche Products Limited, Hertfordshire, United Kingdom, 10 The Royal Marsden NHS Foundation Trust, London, United Kingdom Introduction: Prognosis for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor gene (EGFR) mutations post tyrosine kinase inhibitor (TKI) failure is poor; more efficacious treatments are therefore needed. The Phase III IMpower150 study (NCT02366143) showed that atezolizumab in combination with bevacizumab, carboplatin and paclitaxel improved progression-free survival and overall survival in chemotherapy- naive patients with metastatic non-squamous NSCLC, including those with EGFR mutations who failed TKI therapy. Methods: From December 2018 to March 2019, the IMpower150 regimen was made available via an Early Access to Medicines Scheme (EAMS) in eligible patients with metastatic non-squamous NSCLC with EGFR activating mutations after failure of appropriate targeted therapies (programme AL40901). We highlight important practical guidance based on the EAMS experience of seven UK oncologists. Results: Three key clinical issues were identified: patient selection, apprehension/practicalities around implementing a four-drug Table 1 (abstract 109) Patient pathway sequences by treatment per line Line 1 (N=1113) Line 2 (n=385) Line 3 (n=94) Treatment n % of line 1 n % of line 2 Treatment n % of cohort n % of line 3 Treatment n % of cohort Chemotherapy 814 73.1 314 81.6 Chemotherapy 152 48.4 79 84.0 Chemotherapy 34 43.0 IO therapy 121 38.5 IO therapy 26 32.9 TT 41 13.1 TT 19 24.1 IO therapy 186 16.7 34 8.8 Chemotherapy 32 94.1 8 8.5 Chemotherapy 8 100.0 IO therapy 2 5.9 TT (ALK and 113 10.2 37 9.6 Chemotherapy 4 10.8 7 7.4 Chemotherapy 2 28.6 EGFR inhibitors) TT 33 89.2 IO therapy 1 14.3 TT 4 57.1