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Studies have shown that the prevalence of RAS and BRAF mutations may differ by tumor sidedness among metastatic colorectal cancer (mCRC) patients. Both mutation status and tumor sidedness may impact survival and disease progression and RAS mutation status has been shown to predict response to anti‐epidermal growth factor receptor (EGFR) therapy. A systematic literature review and meta‐analysis were conducted to estimate the pooled prevalence of RAS and BRAF mutations by tumor sidedness in studies of mCRC patients. Forty‐four studies comprising 15 981 mCRC patients tested for RAS and/or BRAF mutations were included in the meta‐analyses. The prevalence of RAS mutations differed significantly by tumor side (32.4% among left‐sided tumors, 41.3% among right‐sided tumors; P = .017), as did the prevalence of KRAS mutations (35.8% among left‐sided tumors, 46.3% among right‐sided tumors; P, A systematic literature review and meta‐analysis were conducted to estimate the prevalence of RAS and BRAF mutations by tumor sidedness in metastatic colorectal cancer (mCRC) patients. RAS, KRAS, and BRAF mutations were found to vary significantly by tumor location, occurring more frequently among right‐sided colon tumors than left‐sided colon tumors. These results inform clinicians and researchers regarding the mCRC patient population and potential targeted patients for anti‐EGFR therapies.

Limited information is available regarding elderly patients experiencing febrile neutropenia (FN). This study evaluated FN-related care among elderly cancer patients who received high/intermediate FN-risk chemotherapy and experienced ≥ 1 FN episodes. We used Medicare data to identify patients aged ≥ 66 years who initiated high/intermediate FN-risk chemotherapy between 1 January 2008 and 31 August 2015 to treat breast cancer (BC), lung cancer (LC), or non-Hodgkin lymphoma (NHL) and had ≥ 1 FN episodes. We identified within-cycle FN episodes for each chemotherapy cycle on Part A inpatient claims or outpatient or Part B claims. We described the FN-related care setting (inpatient hospital, outpatient emergency department [ED], or outpatient non-ED) and reported mean total cost of FN-related care per episode overall and by care setting (adjusted to 2015 US$). We identified 2138, 3521, and 2862 patients with BC, LC, and NHL, respectively, with ≥ 1 FN episodes (total episodes: 2407, 3840, 3587, respectively). Most FN episodes required inpatient care (BC, 88.1%; LC, 93.0%; NHL, 93.2%) with mean hospital length of stay (LOS) 6.2, 6.5, and 6.8 days, respectively. Intensive care unit admission was required for 20.4% of BC, 29.0% of LC, and 25.7% of NHL hospitalizations (mean LOS: 4.7, 4.7, 5.5 days, respectively). The mean total cost of FN care per episode was $11,959 BC, $14,388 LC, and $15,006 NHL, with inpatient admission the costliest care component ($11,826; $14,294; and $14,873; respectively). Among elderly patients with BC, LC, or NHL who experienced FN, most FN episodes required costly hospital care, highlighting the FN burden on healthcare systems.

Two recent evaluations reported that many cancer chemotherapy patients discontinue pegfilgrastim prophylaxis (PP) following the first cycle, and that these patients have a higher subsequent risk of febrile neutropenia (FN). Such evidence is based principally on the experience of younger adults with private healthcare coverage, and the generalizability of results to elderly Medicare patients is unknown.A matched-cohort design and data from the Medicare Claims Research Identifiable Files were employed. The source population comprised cancer patients aged ≥65 years who received chemotherapy with intermediate/high-risk for FN and first-cycle PP. From the source population, beginning with the second cycle, all patients who received PP in all previous cycles were identified. From this sub-set, patients who did not receive PP in the cycle of interest ("comparison patients") were matched to those who received PP in that cycle ("PP patients"); the same process was repeated for subsequent cycles. Odds ratios (OR) for FN (broad and narrow definitions) were estimated using generalized estimating equations.Among 77,616 elderly patients in the source population, 5.3% did not receive second-cycle PP and were matched to those who did. In cycle 2, FN odds were significantly higher among comparison patients vs PP patients when employing the broad definition (OR = 1.9, p .001) and the narrow definition (OR = 2.1, p .001). Results for subsequent cycles (broad definition: OR = 2.0, p .001; narrow definition: OR = 2.1, p .001) and for the last cycle (broad definition: OR = 1.4, p = .060; narrow definition: OR = 1.7, p = .055) were largely comparable.In this large-scale evaluation of elderly Medicare patients who received myelosuppressive chemotherapy and first-cycle PP in recent US clinical practice, FN risk was substantially lower among patients who continued to receive PP in subsequent cycles vs those who discontinued PP.

Monoclonal antibody inhibitors of the epidermal growth factor receptor (EGFR) have been shown to improve outcomes for patients with metastatic colorectal cancer (mCRC) without RAS gene mutations. However, treatment with anti-EGFR agents can be associated with toxicities of the skin, nails, hair, and eyes. Because these dermatologic toxicities can result in treatment discontinuation and affect patient quality of life, their management is an important focus when administering anti-EGFR monoclonal antibodies. The present systematic review describes the current data reporting the nature and incidence of, and management and treatment options for, dermatologic toxicities occurring during anti-EGFR treatment of mCRC. A search of the National Library of Medicine PubMed database from January 1, 2009, to August 18, 2016, identified relevant reports discussing dermatologic toxicity management among patients with mCRC receiving anti-EGFR therapy. The studies were grouped by type and rated by level of evidence using the GRADE approach developed by the Agency for Healthcare Research and Quality. Overall, 269 reports were reviewed (nonrandomized trials, n = 120; randomized trials, n = 31; retrospective studies, n = 15; reviews, n = 39). Dermatologic toxicity of any grade occurs in most patients who receive anti-EGFR therapy; approximately 10% to 20% of patients experienced grade 3/4 toxicity. The most common dermatologic toxicities include papulopustular/acneiform rash, xerosis, and pruritus; however, nail changes, hair abnormalities, and ocular conditions also occur. Guidance for managing these toxicities includes the use of inexpensive emollient ointments and moisturizers, avoidance of sun exposure, avoidance of irritants, and the use of short showers. Several studies also found that preemptive treatment was more effective than reactive treatment at limiting the incidence and severity of skin toxicity. With appropriate treatment, the dermatologic toxicities associated with anti-EGFR monoclonal antibody therapy can be managed, minimizing patient discomfort and the need for therapy interruption and/or discontinuation. Additionally, preemptive treatment can reduce dermatologic toxicity severity, ultimately yielding better quality of life.

Aim: A confirmed wild-type RAS tumor status is commonly required for prescribing anti-EGFR treatment for metastatic colorectal cancer. This noninterventional, observational research project estimated RAS mutation prevalence from real-world sources. Materials & methods: Aggregate RAS mutation data were collected from 12 sources in three regions. Each source was analyzed separately; pooled prevalence estimates were then derived from meta-analyses. Results: The pooled RAS mutation prevalence from 4431 tumor samples tested for RAS mutation status was estimated to be 43.6% (95% CI: 38.8–48.5%); ranging from 33.7% (95% CI: 28.4–39.3%) to 54.1% (95% CI: 51.7–56.5%) between sources. Conclusion: The RAS mutation prevalence estimates varied among sources. The reasons for this are not clear and highlight the need for further research.

Introduction This study aimed to describe medical oncologist’s opinions and perceptions regarding the management of dermatologic toxicities among metastatic colorectal cancer (mCRC) patients who were treated with panitumumab in the USA and assess if there were differences across demographic and clinical characteristics. Methods We developed a survey based on the current literature and expert opinions regarding the management of dermatologic toxicities. The survey was implemented online in September 2016. Eligible oncologists were board certified and had treated at least five new or continuing patients with mCRC in the last 3 months, among whom at least three patients had received or were currently receiving panitumumab. Results A total of 250 oncologists completed the survey. The data suggest that approximately 82% of patients received recommendations for moisturizer, 88% for sunscreen and 67% for ultraviolet (UV)-protective garments prior to or at the time of initiation of panitumumab therapy. There were minor differences in how dermatologic toxicities were managed across specific demographic or clinical groups. The data also suggest that the management associated with panitumumab use among mCRC patients can be greatly improved. Conclusions Our results highlight the urgent need for heightened education regarding dermatologic toxicity management among oncologists who treated mCRC patients with panitumumab. Easily implemented strategies, such as moisturizer, sunscreen, and UV-protective garments should be recommended to all patients. Funding Amgen, Inc. Plain Language Summary Plain language summary available for this article.

e16252 Background: Treatment options remain limited for pts newly diagnosed with mPDAC. NCCN and ASCO guidelines both recommend treatment with FOLFIRINOX or gemcitabine plus nab-paclitaxel in the first line (1L) setting for pts with mPDAC and good performance status. Over 80% of randomized clinical trials (RCTs) studying treatments for mPDAC have failed to meet their primary endpoints. Recently published analyses have utilized real-world (RW) data to compare outcomes between pts enrolled in clinical trials and RW pts. This study sought to identify the eligible population of pts with mPDAC treated with FOLFIRINOX in the 1L setting who would meet RCT eligibility criteria for the phase 1/2 study (NCT02551991) evaluating NALIRIFOX for pts with previously untreated locally advanced or mPDAC, and to assess their survival outcomes. Methods: This retrospective observational study utilized the Flatiron Health EHR database. Data were analyzed for adult pts diagnosed with mPDAC between January 2016 and February 2020 who initiated treatment with FOLFIRNOX in 1L within 90 days of their diagnosis for metastatic disease. Eligibility criteria from the phase 1/2 trial were applied to select a population of RW pts who may have been eligible to enter the RCT. Pts meeting the following criteria were included: good performance scores (ECOG 0-1), adequate hematological, hepatic, and renal function, were recovered from the effects of surgery, were untreated in the year prior to initiating 1L, and had no evidence of a different cancer in the last three years. Kaplan-Meier analyses were used to assess the median overall survival (mOS) from the start of 1L FOLFIRNOX treatment. Results: Of the 1,210 pts treated with 1L FOLFIRINOX, 652 pts (53.8%) met less stringent versions of the RCT eligibility criteria in which missing values were deemed to indicate normal function/performance; 244 pts (20.2%) met the more stringent criteria and had complete data. The most restrictive selection criteria were the requirements for adequate hematological, hepatic, and renal function and having received prior therapy. The median age at treatment initiation among the 244 pts was 64 years (IQR: 58 – 70). 153 pts were male (62.7%), 158 were White (64.8%), and ECOG scores of 0 and 1 were split among the cohort 50%/50%. The mOS observed for the 244 pts was 10.1 months (95% CI: 9.1 – 11.3). The reported mOS from the phase 1/2 trial of NALIRIFOX was 12.6 months (8.7 – 18.7). Conclusions: This study demonstrates that RW data may be used to select a comparator cohort for a clinical trial. Initial estimates suggest NALIRIFOX pts from the RCT experienced longer survival than those receiving 1L FOLFIRINOX in the RW setting. Further analysis is necessary to minimize the effects of confounding and the differences in data collection between the RW and the RCT settings.

Two recent evaluations reported that risk of febrile neutropenia (FN) may be higher when pegfilgrastim prophylaxis (PP) is administered on same day as chemotherapy rather than per recommendation (1-3 days following chemotherapy). Such evidence is based largely on the experience of younger privately insured adults and may not be generalizable to older patients in US clinical practice.A retrospective cohort design and data from Medicare Claims Research Identifiable Files (January 2008-September 2015) were employed. Patients were aged ≥65 years, had breast cancer or non-Hodgkin's lymphoma, received chemotherapy with intermediate/high risk for FN, and received PP in ≥1 cycle; cycles with PP were stratified based on administration day (same-day ["Day 0"] vs. 1-3 days following chemotherapy ["Days 1-3"]) and were pooled for analyses. Adjusted odds ratios (ORs) for FN during the cycle were estimated for patients who received PP on Day 0 versus Days 1-3.Study population included 65,003 patients who received PP in 261,184 cycles; in 5% of cycles, patients received PP on Day 0. Incidence proportion for FN in cycle 1 was 11.4% for Day 0 versus 8.4% for Days 1-3; adjusted OR was 1.4 (p .001). Incidence proportion for FN when considering all cycles was 7.7% for Day 0 and 6.0% for Days 1-3; adjusted OR was 1.3 (p .001). Adjusted ORs when considering all cycles and only inpatient FN episodes (1.3, p .001) and the narrow definition for FN (1.5, p .001) were similar.Among Medicare patients receiving chemotherapy and PP in US clinical practice, PP was administered before the recommended timing in 5% of cycles and FN incidence was significantly higher in these cycles. Along with prior research, study findings support recently updated US practice guidelines indicating that PP should be administered the day after chemotherapy.

e18933Background: Few population-based studies examine febrile neutropenia (FN)-related care and associated costs in elderly Medicare cancer patients (pts). Methods: Using Medicare 20% sample data,...

681 Background: There is evidence to suggest that tumor biology and pathology differ for right- and left-sided colon tumors which may affect treatment efficacy and clinical outcomes. Therefore, we conducted a systematic review and meta-analysis of the available scientific literature to summarize the prevalence of RAS and BRAF mutations by primary tumor location and to identify potential sources of heterogeneity in mutation prevalence. Methods: This study was conducted in accordance with PRISMA guidelines. Using comprehensive search strings, several medical research databases were queried and relevant variables abstracted including tumor mutation prevalence, study country, metastasis site, tissue source, study design, study dates, median age of the cohort, mutation assessment method, and length of follow-up. Results: Final abstraction was performed on 40 articles, 36 observational studies and 4 randomized trials. Most studies were from Europe (n = 16), followed by Asia (n = 11), USA, (n = 7), Australia (n = 3), and the remaining 3 were conducted in multiple countries. The proportion of males in each study ranged from 37% to 72%, and the mean age ranged from 55 to 76 years. The prevalence of all RAS mutations was significantly higher among right-sided colon tumors than left-sided colon tumors (44%, 95% Confidence Interval [CI]: 38 – 50% vs 34%, 95% CI: 29 – 38%; p = 0.009). BRAF mutation prevalence was also higher in right-sided tumors (16.1%, 95% CI: 13.1 – 19.6% vs 4.4%, 95% CI: 3.4 – 5.8%; p < 0.0001). Conclusions: This systematic review and meta-analysis found that mutation prevalence varied by primary tumor right- or left-sided location among mCRC patients. Some of this variation may be explained by study characteristics such as mutation assessment method, country and length of follow-up. Further research will help to better understand treatment and outcome implications of tumor sidedness and mutation prevalence.

678 Background: We sought to determine the proportion of patients with mCRC in the United States who were tested for KRAS, NRAS, and BRAF mutational status before any 1st line of therapy. Patient demographics that may influence testing, and the turnaround time between key events associated with biomarker testing and utilization of biomarker results were also assessed. Methods: The study utilized the Oncology Services Comprehensive Electronic Records (OSCER) 2.0 dataset, provided by Flatiron Health, which includes mCRC patients from community cancer centers across the United States. Biomarker results are recorded in the Flatiron Electronic Health Record when available. The proportion of patients tested or not tested for KRAS, NRAS, and BRAF mutational status before 1st line of therapy between 2013 and 2017 was calculated, as were the differences in the patient demographics. The median number of days between the date of tissue collection, the date the tissue was received by the laboratory, and the date the oncologist received the test results was calculated. Results: Of the 13,437 patients included in the analysis, the proportion of patients who were tested prior to 1st line of therapy was as follows: KRAS, 30.8%,; NRAS, 9.9%; BRAF, 11.5%. Age, insurance type, race, and presence of liver metastases were all statistically significant factors that influenced testing. Specifically, younger, commercially-insured, Caucasian patients, and those who had liver metastases were more likely to be tested. For KRAS testing, the median time between tissue collection and tissue received by the laboratory was 26 days. Receipt of the results by the oncologist took an additional median number of 27 days. Conclusions: This study found that the testing rate for these key mCRC biomarkers was less than 31% and that the median number of days to assess biomarker results was 26. Further studies conducted in various settings, such as academic cancer clinics, are needed to investigate this low proportion of testing and long time to assess results.

e15170 Background: Skin toxicity can be a limiting factor for the use of anti-EGFR therapies, such as panitumumab, and there are currently no standard practice guidelines for rash management in the United States (U.S.). This study aimed to evaluate if there were regional or practice setting differences in strategies used among oncologists to manage EGFR rash, including utilization of dermatologic and nursing support. Methods: 250 practicing oncologists who had treated at least three mCRC patients with panitumumab in the last year completed an online survey to report their opinions and perceptions regarding skin toxicity management strategies. Participants reported if they were affiliated with an academic/university or a community-based practice. Participants were stratified into years of practice post-fellowship ( < 10 and > 10 years) and geographic region of primary practice (West, Midwest, Northeast, Southern U.S.). Results: Oncologists surveyed did not consistently utilize dermatology support. 40% (n = 99) of practicing oncologists surveyed reported consulting a dermatologist “occasionally.” Less than 5% reported “always” consulting dermatology and 6% reported “never” utilizing dermatology support. Utilization of dermatology support varied significantly by region. In the Southern US more oncologists reported “never” consulting dermatology while in the Midwest more oncologists reported “always” utilizing dermatology support (p = 0.05). While dermatology was inconsistently utilized, oncologists frequently utilized nursing support to minimize and manage anti-EGFR skin toxicity. 73% (n = 182) of oncologists engaged nursing support to “monitor skin toxicity during treatment” and 70% (n = 175) of oncologists had nursing support to “educate on skin toxicity prior to starting treatment.” Conclusions: While nursing support is consistently utilized by oncologists in the management of EGFR rash in mCRC patients treated with panitumumab, use of dermatology support was inconsistent and varied significantly by region. This lack of consistency in toxicity management strategies highlights the need for increased physician education.

e15169 Background: The Skin Toxicity Evaluation Protocol with Panitumumab (STEPP) and the Japan Skin Toxicity Evaluation Protocol with Panitumumab (J-STEPP) were open-label, randomized trials that were designed to evaluate differences in preemptive versus reactive management of dermatologic toxicities associated with panitumumab among patients with mCRC. The objective of this study was to evaluate if there were differences in the knowledge and application of STEPP and J-STEPP among oncologists who self-identified as primarily managing EGFR rash preemptively or reactively. Methods: A total of 250 practicing oncologists who had treated at least three new or continuing mCRC patients with panitumumab in the last year completed an online survey to report their opinions and perceptions regarding the management strategies for mCRC patients who are treated with panitumumab. Preemptive treatment was described in the survey as beginning treatment “prior to the appearance of rash” and reactive treatment was defined as beginning treatment “after signs of rash.” Results: Of the 250 oncologists who participated in this study, n = 58 (23%) reported treating 100% of their patients preemptively and n = 38 (15%) reported treating 100% of their patients reactively. A significantly higher proportion of preemptive treaters than reactive treaters reported following the skin management strategies from STEPP or J-STEPP when managing panitumumab-related skin toxicity (31% vs 13%, p = 0.02). When asked if skin moisturizer, sunscreen, over-the-counter topical steroids, prescription topical steroids, oral antibiotics, topical antibiotics, or UV protective garments were most critical in the preemptive management of panitumumab-related skin toxicity, preemptive treaters more likely to report using oral antibiotics and reactive treaters more like to report using sunscreen (p = 0.05). Conclusions: The results of this survey highlight the wide variability in the management of EGFR-related rash among mCRC patients who are treated with panitumumab and they highlight the need for heighted education among oncologists who treat mCRC patients with panitumumab.

639 Background: Dermatologic toxicity can be a limiting factor for the use of anti-EGFR therapy such as panitumumab. There is a paucity of real world data regarding the management of dermatologic toxicity among metastatic colorectal cancer (mCRC) patients treated with panitumumab in the United States (U.S.). The objective of this study is to describe oncologist's opinions regarding timing of skin rash management in relation to the initiation of treatment and perceptions regarding rash management strategies. Methods: A total of 125 oncologists were recruited from a national database via a third independent party. Eligible oncologists (i.e.: licensed and practicing oncologist who had treated at least three new or continuing mCRC patients with panitumumab in the last year) completed an online survey to report their opinions regarding the grade and type of dermatologic toxicities seen and their perceptions about management strategies for mCRC patients who are treated with panitumumab. The timing of rash management initiation was defined as pre-emptive (prior to the appearance of the rash) or reactive (after any signs of skin rash). Results: Based upon their collective experience, oncologists expect that 44% of patients will develop acneiform rash while on treatment. More than half (58%) of the oncologists reported they did not follow any practice guidelines regarding the management of dermatologic toxicities. The oncologists reported that they pre-emptively initiated the management of dermatologic toxicities in 53% of their patients. Skin moisturizer and sunscreen were reported to be the most critical preemptive management approach, while skin moisturizer, over-the-counter topical steroids, and oral antibiotics were reported to be the most critical reactive management tools for Grades 1, 2, and 3, respectively. Conclusions: Despite evidence from randomized controlled trials, a majority of oncologists do not follow guidelines for dermatologic management of EGFR-I rash. There is a clear need for better physician education and awareness of mitigation strategies for skin toxicity management in mCRC patients treated with panitumumab.

638 Background: Our objective was to use real world data to evaluate of the treatment continuum of bevacizumab (Bmab), cetuximab (Cmab), panitumumab (Pmab) or no biologics across 1st, 2nd, and 3rd lines among metastatic colorectal cancer (mCRC) patients who were treated at community cancer centers in the United States. This objective was applied separately to patients with confirmed KRAS, NRAS, or BRAF wild-type (WT) or mutation (MUT) status, as well as patient who did not receive biomarker testing (UNK). Methods: This descriptive study utilized data from the Oncology Services Comprehensive Electronic Records (OSCER) database. It included 5,446 (2,064 WT, 1,807 MUT, and 1,575 UNK) patients diagnosed with mCRC between 1/1/2011 and 8/31/2015. Patients were stratified into the following mutually-exclusive categories in 1st, 2nd line, and 3rd line: Pmab only, Cmab only, Bmab only, or no biologic. Patients who survived and continued therapy were followed through the lines of therapy. Results: 23.8% of WT, 36.3% of MUT and 49.5% of UNK patients did not receive a biologic in 1st line. There were 1,003 WT patients who were treated with Bmab in 1st. Of those, n=587 (58.5%) survived and elected to continue treatment in 2nd line as follows: n=221 (37.6%) continued with Bmab, n=216 (36.8%) initiated Cmab, n=65 (11.1%) initiated Pmab, and n=85 (14.5%) received no biologic in 2nd line. Of the 221 WT patients who received Bmab in 1st and 2nd line, n=129 (58.4%) survived and initiated 3rd line treatment, of which n=20 (15.5%) received Bmab in 3rd line. There were 127/2,604 (4.9%) WT patients who were treated with Pmab in 1st line. Of those 127 patients, n=46 (36.2%) survived and elected to continue treatment in 2nd line as follows: n=11 (29.3%) continued treatment with Pmab in 2nd line, while n=14 (30.4%) initiated treatment with Bmab, n=4 (8.7%) initiated treatment with Cmab, and n=16 (36.4%) did not receive a biologic in 2nd line. Conclusions: A small proportion of patients continued treatment with the same biologic throughout subsequent lines of therapy. Many patients were not treated with a biologic in any line, even if they were confirmed WT.

663 Background: There is limited observational data on the use of RAS test results and treatment patterns with chemotherapy and biologics among metastatic colorectal cancer (mCRC) patients. Our objective was to use real world data to evaluate the treatment sequences of mCRC patients who have wild-type RAS (KRAS, NRAS), or BRAF and who are treated at community cancer clinics within the United States (U.S.). Methods: The sample included 536 patients in the Oncology Services Comprehensive Electronic Records (OSCER) database who were diagnosed with mCRC between 1/1/2011 and 8/31/2015. All patients had available treatment data and were confirmed to have wild-type RAS or BRAF. Patients were stratified into mutually-exclusive categories based on 1st line treatment with chemotherapy in combination with either bevacizumab (Bmab), cetuximab (Cmab), panitumumab (Pmab), a combination of Pmab, Cmab or Bmab, or no biologics. Descriptive statistics were used to summarize the data. Results: The demographics of the sample were as follows: mean age 67 years (standard deviation = 12), 55% male, 70% White, and 50% with ECOG value of zero. The use of Bmab, Cmab, or Pmab in combination with chemotherapy in 1st line treatment was follows: Bmab only (n = 270, 50%), Cmab only (n = 81, 15%), Pmab only (n = 28, 5%), and a combination of either Bmab, Cmab and/or Pmab (n = 6, 1%). No biologics were administered to 151 (28%) of the sample in 1st line. There were no statistically significant differences in age, gender, race, insurance type, region of the U.S. or ECOG status at mCRC diagnosis across the 1st line treatment categories. Of the 385 patients who received a biologic in 1st line, 94 (24%) of those who survived and selected to continue treatment received a biologic in 2nd line. Of these 94 patients, 25 (27%) of those who survived and selected to continue treatment also received a biologic in 3rd line. Conclusions: Bmab was the most commonly-used biologic among mCRC patients with wild-type RAS or BRAF in this descriptive study. Future research is needed to better understand what factors impact treatment decisions among mCRC patients.

598 Background: Anti-EGFR therapies are recommended for metastatic colorectal cancer (mCRC) patients with confirmed wild-type RAS (exons 2, 3, 4 of KRAS and NRAS) status. There is limited published information on the prevalence of RAS mutations using real world data. The objective of this study was estimate the prevalence of RAS and BRAF mutations among patients with mCRC in the Middle East and Northern Africa (MENA) in an effort to inform the rationale for biomarker testing and treatment choice. Methods: The study included 1,669 patients from August 2013 to July 2015 with mCRC from Algeria, Bahrain, Egypt, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Qatar, Saudi Arabia, and the United Arab Emeritus. Information on RAS mutation status was obtained from one pathology lab using High Resolution Melting Analysis. Extended RAS analysis was conducted in a subset of patients, including: overall RAS (exon 2, 3, 4 of KRAS and NRAS; n = 750), KRAS exon 2 (n = 750), KRAS exon 3 and 4 (n = 507), NRAS exon 2, 3, and 4 (n = 507), and BRAF exon 15 (n = 78). The proportion of patients with each mutation was summarized. Results: The overall RAS mutation in the full sample was 35.3% (n = 589/1669). The observed mutation for KRAS exon 2 in a subset of patients with extended RAS analysis (n = 750) was 32.4% (243/750). Out of the subjects with wild-type exon 2 (n = 507), the observed mutations rates were as follows: KRAS exon 4 (20/507 = 3.9%), KRAS exon 3 (13/507 = 2.6%), NRAS exon 2 (7/507 = 1.4%), NRAS exon 3 (6/507 = 1.2%), and NRAS exon 4 (0%). The prevalence of BRAF exon 15 was 3.8% (3/78). The most robust data on specific RAS mutations was obtained from Algeria, Egypt, and Saudi Arabia. The prevalence of KRAS exon 2 mutations in these countries was as follows: Algeria (n = 33/86 = 38.4%), Egypt (n = 83/303 = 27.4%), Saudi Arabia (n = 85/245 = 34.7%). Conclusions: To our knowledge, this is the first study to evaluate the prevalence of RAS and BRAF mutations in the Middle East using real world data. The results of this descriptive study illustrate that there is variation in the prevalence of RAS and BRAF mutations in MENA.