Citations

4578 Background: Gemcitabine is commonly used in patients with cholangiocarcinoma with a response rate of 20–30% and median overall survival of 6–10 months. Pemetrexed’s mechanism of action and tolerability in patients with hepatic dysfunction makes it a potential agent for cholangiocarcinoma. Methods: Patients with unresectable, previously untreated biliary tract cancers were eligible for participation. Patients received pemetrexed 500 mg/m2 IV over 10 minutes and gemcitabine 800 mg/m2 IV at 10 mg/m2/minute on days 1 and 15 of an every 4 week schedule with vitamin B12 and folate supplementation. The primary end-point is 6-month survival with a planned accrual of 59 patients. Results: 58 eligible patients are included in this analysis. 93% had metastatic disease. Median age was 61 (range: 40 - 81). Median follow-up was 6.5 months (range: 3.3 - 23.2). Median of 3 cycles of treatment was given (range: 1 - 10). Reasons for stopping treatment included disease progression (57%), adverse events (20%), refusal (17%), death on- study (4%), and other medical problems (2%). 6-month survival was 52% (95% CI: 40 - 68%). Median survival was 6.3 months (95% CI: 5.4 - 8.0 months) and median time-to-progression was 3.8 months (2.4 - 5.0). 46 of 58 patients (79%) experienced at least one grade 3+ AE (at least possible attribution), and 26 patients (45%) experienced at least one grade 4 AE (at least possible attribution), most of which were due to grade 4 neutropenia. Conclusions: This study shows similar results to what would be expected with gemcitabine alone. The addition of pemetrexed, as with other agents, has not significantly enhanced the activity of gemcitabine. Supported by NIH Grant CA25224- 18. [Table: see text] No significant financial relationships to disclose.

696 Background: A number of treatments for metastatic renal cell carcinoma (RCC) have been FDA approved since December, 2005. Trials evaluating these agents excluded non-clear cell histologies and therefore the efficacy of these treatments remains unclear in patients (pts) with metastatic non-clear cell RCC (mncRCC). Methods: This is a single arm Phase II study designed to determine the efficacy of pazopanib in mncRCC. Treatment was pazopanib 800 mg by mouth daily until progression or intolerability of treatment. Dose reductions were allowed for toxicity with dose level -1 being 600 mg daily and dose level -2, 400 mg daily. Cycles were every 28 days. Main eligibility criteria included: (1) age ³ 18 years old; (2) histologic confirmation of ncRCC; (3) ECOG Performance Status (PS) 0, 1, or 2; (4) up to one prior treatment for mncRCC (5) measurable or non-measurable metastatic disease per RECIST criteria. The primary endpoint was overall survival rate at 12 months. Secondary endpoints were best tumor response rates after two cycles, PFS, OS and toxicity. Results: 38 pts were enrolled between May 16, 2013 and February 1, 2018. 35 pts were evaluable for primary endpoint. Median age 63 years old and 22/35 (62.9%) were male. Most common histology was papillary RCC, 14/35 (40%), and most common number of metastatic sites was 1. 29/35 (82.9%) had prior nephrectomy and 30/35 (85.7%) had no prior systemic therapy. Median number of cycles was 5. 12-month OS was 65.7% (90% CI, 50.5-78.9%). Best response in first 2 cycles: PR 11%, SD 60%, PD 9%, not evaluated 20%. Median PFS was 7.5 months (90% CI, 5.0-11.0); median OS 18.9 months (90% CI, 13.0-NE). Grade 3 / 4 AEs seen in 25 pts with hypertension, transaminitis and abdominal pain being most common (seen in >10%). Conclusions: There are limited data about the efficacy of available therapies for mncRCC. This study shows that pazopanib has similar efficacy compared to historical data in clinical trials using other TKIs in mncRCC. The safety profile of pazopanib in pts with mncRCC was found to be similar to that found in prior clinical trials studying pazopanib. Our findings warrant further investigation into the utility of pazopanib in metastatic ncRCC. Clinical trial information: NCT01767636.

Background: Adherence to surveillance guidelines in resected colon cancer has significant implications for patient morbidity, cost of care, and healthcare utilization. This study measured the underuse and overuse of imaging for staging and surveillance in stage I–II colon cancer. Methods: The OptumLabs database was queried for administrative claims data on adult patients with stage I–II colon cancer who underwent surgery alone in 2008 through 2016. Use of PET and CT imaging was evaluated during both initial staging (n=6,921) and surveillance for patients with at least 1 year of follow-up (n=5,466). “High use” was defined as >2 CT abdominal/pelvic (CT A/P) or PET scans per year during surveillance. Results: Overall, 27% of patients with stage I–II colon cancer did not have a staging CT A/P or PET scan and 95% did not have a CT chest scan. However, rates of staging CT A/P and CT chest scans increased from 62.0% (2008) to 74.8% (2016) and from 2.3% (2008) to 7.1% (2016), respectively. Staging PET use was overall very low (5.2%). During surveillance, approximately 30% of patients received a CT A/P or PET and 5% received a CT chest scan within the first year after surgery. Of patients who had surveillance CT A/P or PET scans, the proportion receiving >2 scans within the first year (high use) declined from 32.4% (2008) to 9.6% (2016) (P = .01). Conclusions: Although PET use remains appropriately low, many patients with stage I–II colon cancer do not receive appropriate staging and surveillance CT chest scans. Among those who do receive these scans during surveillance, high use has declined significantly over time.

Abstract Introduction: The role of surveillance imaging in diffuse large B-cell lymphoma (DLBCL) after treatment with curative intent is debated. In 2013, the American Society of Hematology (ASH) Choosing Wisely® campaign (Hicks LK, et al. Blood 2013) released a recommendation to "limit surveillance CT scans in asymptomatic patients following curative-intent treatment for aggressive lymphoma." This was based on previous studies demonstrating a lack of survival benefit as well as a significant impact on the patient in terms of cost, anxiety, incidental findings and radiation exposure. Similar findings have been described regarding the use of PET imaging, especially in low risk patients. We aimed to study the changes in practice patterns of surveillance imaging for DLBCL survivors treated with curative intent before and after the publication of the ASH Choosing Wisely® campaign. Methods: Administrative claims data from a large U.S commercial insurance database (OptumLabs Data Warehouse) were used to retrospectively identify adult patients with an incident diagnosis of DLBCL between 2008 and 2016 and at least one year of follow-up. We excluded those who did not receive treatment with curative intent: RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) x 6 cycles or RCHOP x 3-5 cycles plus radiation. Patients were also excluded if they had a co-existing or second cancer, or if they received any chemotherapy/radiation during their surveillance period, as to exclude anyone with a recurrence of their lymphoma. The surveillance period started 90 days after the last chemotherapy or radiation and continued for the duration of follow-up. Surveillance imaging was defined as any PET, PET-CT, CT chest, CT abdomen, and/or CT pelvis. To examine trends over time, three time periods were defined: 2008-2010, 2011-2013 and 2014-2016. The Cochran Armitage test was used to test the trend hypothesis. Results: A total of 1,472 patients were included. Cohort characteristics by time period are described in Table 1. Surveillance imaging frequency decreased from 84% in Year 1 of surveillance to 43% in Year 5 (Figure 1). Overall, surveillance imaging during the first 3 surveillance years significantly decreased over the three time periods (Figure 2) (P<0.01 for Years 1 and 2, P=0.04 for Year 3). Imaging surveillance for the first two years of surveillance did not significantly decrease from 2008-2010 to 2011-2013 (P>0.05), but significantly decreased from 2011-2013 to 2014-2016 (P<0.01). Of the groups that received imaging surveillance during year 1, the median number of scans during the first year was 2 (inter-quartile range, 1-2) and did not significantly change over time. In addition, PET/PET-CT surveillance decreased from 49% in Year 1 to <10% in Year 5. PET/PET-CT also decreased over the three time periods, from 62% (2008-2010) to 48% (2011-2013) to 43% (2014-2016) during the first year of surveillance and 40% to 31% to 25% during the second year. Younger age (<65 years versus ≥65 years) was associated with higher imaging utilization (86% versus 81%, respectively), and specifically PET/PET-CT utilization (55% versus 43%, respectively), during the first year of surveillance. However, race (white versus non-white) did not significantly affect imaging (85% versus 83%) or PET utilization (50% versus 47%) during the first year of surveillance. Conclusions: Our study demonstrates that the rate of surveillance CT and PET imaging in DLBCL patients treated with curative intent decreased significantly in the years after the publication of the ASH Choosing Wisely® campaign. However, over half of the DLBCL patients diagnosed in 2014-2016 continued to undergo surveillance imaging, indicating either incomplete guideline dissemination or ongoing debate regarding optimal surveillance practice. Future studies are necessary to determine whether such a decline in surveillance imaging is sustained and to examine factors (patient, provider, and payer) associated with surveillance imaging in DLBCL. Disclosures No relevant conflicts of interest to declare.

e16559 Background: ARVs that develop early during treatment with abiraterone acetate/ prednisone (AA/P) may play a role in treatment resistance. We evaluated metastatic site and whole blood mRNA expression of full-length AR (AR-FL) and ARVs to characterize treatment-emergent ARVs (TE-ARVs) from men with mCRPC pre- and post- 12 weeks of AA/P collected in a prospective clinical trial (NCT#01953640). Methods: RNAseq performed on paired metastatic site biopsy (n = 40) and whole blood (n = 25) passed quality control. Reads were aligned to the GRCh38 reference genome with the spliced-alignment TopHat2 package. AR-FL or ARVs were detected if ≥ 2 splice reads aligned to unique splice junctions for AR-FL, AR-8, AR-45, AR-23, AR-V3, AR-V5V6, AR-V7, AR-V8, AR-V9, AR-V10, AR-V12, AR-V13, and AR-V14, and normalized to splice reads per million (SRPM). Cox proportional hazard regression analysis was performed on AR-FL and AR-Vs with ≥1 SRPM for association with time to treatment change (TTTC). Results: In metastatic site biopsies post-AA/P, the average number of splice reads was 27,376,541 (range 7,753,998 to 62,456,773). The median number of ARVs detected was 2 (range 0-8), with a total of total of 110 ARVs identified (Table). Dynamic shifts in ARV profiles were observed post-AAP, with 41 TE-ARVs identified in 17 unique patients. The most common TE-ARV was AR-8 (n = 8), followed by AR-45 (n = 5), AR-23 (n = 5), and AR-V7 (n = 4). The presence of AR-V7 post-AAP was adversely associated with TTTC (hazard ratio 2.46, p = 0.013). The identification of early TE- ARV was not associated with TTTC. In whole blood samples, post-AA/P detection of AR-FL was low (n = 3) and no ARVs were detected. Conclusions: No specific patterns were observed in ARV profiles obtained in the metastatic biopsies after 12 weeks of treatment with AA/P. Clinical trial information: 01953640. [Table: see text]

5029 Background: Pembro had activity as monotherapy in pretreated advanced mCRPC. Data are presented here from cohort B (pembro + docetaxel/prednisone) of KEYNOTE-365 (NCT02861573), a phase 1b/2 umbrella study to test combinations in mCRPC. Methods: Pts who progressed on or became intolerant to ≥4 wk of abi or enza in the prechemotherapy mCRPC state and progressed within 6 mo before screening were eligible. Pts received pembro 200 mg IV with docetaxel 75 mg/m2 IV Q3W plus prednisone 5 mg orally twice daily. The primary end points were safety and PSA response rate (confirmed PSA decrease ≥50%). Key secondary end points were investigator-determined ORR (RECIST v1.1), disease control rate (DCR: CR+PR+SD ≥6 mo), time to PSA progression, rPFS, and OS. Results: 72 pts (median age, 68 y; visceral disease, 36%; measurable disease, 50%) began pembro + docetaxel. Median (95% CI) follow-up was 10 (8-12) mo. Efficacy is outlined in the table. Treatment-related AEs occurred in 69 (96%) pts; most frequent (≥30%) were alopecia (43%), fatigue (40%), and diarrhea (39%). Grade 3-5 treatment-related AEs occurred in 27 (38%) pts, including 2 deaths from treatment-related AEs (pneumonitis). Most commonly reported immune-mediated AEs were infusion-related reactions (11%) and colitis (10%). Conclusions: Pembro + docetaxel/prednisone has activity in pts with mCRPC who previously progressed on second-generation hormone therapy. AEs were considered mild for the treatment combination. Clinical trial information: NCT02861573. [Table: see text]

170 Background: Pembro had antitumor activity as monotherapy in pretreated advanced mCRPC (KEYNOTE-028; KEYNOTE-199). KEYNOTE-365 (NCT02861573) is a phase 1b/2 umbrella study testing combinations in mCRPC; we report early results from cohort B combining pembro + docetaxel in mCRPC. Methods: Pts who failed or became intolerant to ≥4 weeks of abi or enza in the pre-chemotherapy mCRPC state received pembro 200 mg IV with docetaxel 75 mg/m2 IV Q3W plus prednisone 5 mg orally twice daily. Pts also progressed within 6 months prior to screening as determined by either PSA progression or radiologic progression in bone or soft tissue. Response was evaluated by PSA levels Q3W and imaging Q9W for first year and Q12W thereafter. Primary end points: safety and PSA response rate (confirmed PSA decline ≥50%). Key secondary end points: investigator-determined ORR (RECIST v1.1), disease control rate (DCR: CR+PR+SD ≥6 mo), time to PSA progression, rPFS, and OS. Results: 72 pts (median age 68 years; PD-L1+ 29%; visceral disease 36%; measurable disease 50%) initiated pembro + docetaxel. Median (95% CI) follow-up was 10 (8-12) mo. Efficacy is outlined in table below. Treatment-related AEs occurred in 69 (96%) pts; most frequent (≥30%) were alopecia (43%), fatigue (40%), and diarrhea (39%). Grade 3-5 treatment-related AEs occurred in 27 (38%) pts, including 2 deaths due to treatment-related AEs (pneumonitis). Conclusions: Combination of pembro + docetaxel/prednisone has activity in pts with mCRPC previously failing anti-hormonal therapy. Observed safety profile for the combination was consistent with known safety profile of each component. Clinical trial information: NCT02861573. [Table: see text]