Citations

BACKGROUNDA prior practice survey revealed variations in the management of patients with sickle cell disease (SCD) and stressed the need for comprehensive guidelines. Here we discuss: 1) common indications for red blood cell exchange (RCE), 2) options for access, 3) how to prepare the red blood cells (RBCs) to be used for RCE, 4) target hemoglobin (Hb) and/or hematocrit (Hct) and HbS level, 5) RBC depletion/RCE, and 6) some complications that may ensue.STUDY DESIGN AND METHODSFifteen physicians actively practicing apheresis from 14 institutions representing different areas within the United States discussed how they manage RCE for patients with SCD.RESULTSSimple transfusion is recommended to treat symptomatic anemia with Hb level of less than 9 g/dL. RCE is indicated to prevent or treat complications arising from the presence of HbS. The most important goals are reduction of HbS while also preventing hyperviscosity. The usual goals are a target HbS level of not more than 30% and Hct level of less than 30%.CONCLUSIONAlthough a consensus as to protocol details may not be possible, there are areas of agreement in the management of these patients, for example, that it is optimal to avoid hyperviscosity and iron overload, that a target Hb S level in the range of 30% is generally desirable, and that RCE as an acute treatment for pain crisis in the absence of other acute or chronic conditions is ordinarily discouraged.

AbstractPositron emission tomography‐computed tomography (PET‐CT) can identify bony lesions, assess disease burden, and detect extramedullary disease (EMD) in patients with multiple myeloma. We retrospectively reviewed records of patients who underwent PET‐CT within 60 days of a new diagnosis (before therapy commenced) to identify the nature and prognostic impact of PET‐CT abnormalities. Patients (N = 313) were seen from April 2005 through June 2017. Of the 234 patients (75%) with focal lesions (FLs), 182 (58%) had at least 3 FLs, 38 (12%) had EMD, and 204 (65%) had documented myelomatous lytic lesions. The median maximum standardized uptake value (SUVmax) for the entire cohort was 5.9 (range 1.5‐48.3). Presence of at least 3 FLs and EMD predicted inferior overall survival (OS); median OS was 57.8 months for patients with 3 or more FLs and 103.6 months for patients with fewer than 3 FLs (P = .003). The median OS was 45.5 and 71.8 months for patients with and without EMD, respectively (P = .004). No clear SUVmax cutoff was predictive of progression‐free survival or OS. PET‐CT is a valuable tool for assessing disease burden and could provide prognostic information about a contemporary cohort of patients with newly diagnosed myeloma who received treatment with novel agents.

11534 Background: To date, there are no validated blood-based biomarkers of predicting response to PD-1 blockade. We previously reported that Bim is a downstream signaling molecule of the PD-1 pathway, and that measurement of Bim levels in circulating T-cells may predict and monitor responses to anti–PD-1 therapy in melanoma. We have identified the existence of sPD-L1 in cancer patients and showed that the sPD-L1 is biologically active and capable of triggering apoptosis in activated T-cells. Here we evaluated T cell Bim and sPD-L1 in the peripheral blood (PB) as biomarkers of response in a cohort of patients with metastatic melanoma and lung cancer undergoing anti-PD1 therapy. Methods: 60 pts treated with anti-PD-1 had PB collected at baseline and at radiographic tumor evaluation. Frequencies of Bim+ T cells and Bim median fluorescence intensity (MFI) were measured by flow cytometry in gated tumor-reactive CD11ahighPD1+ CD8+ T cells. We also measured levels of sPD-L1 at baseline and serially during treatment with sPD-L1 ELISA. Baseline Bim and sPD-L1 levels and percent change in Bim levels in patients (pts) who had a radiographic response (CR/PR) were compared to those who had progressive disease (PD) at 12 wks. Results: Similarly to previously reported preliminary data, pts with objective response (CR/PR, 15/60) after 4 cycles of anti-PD1 therapy had higher frequency of Bim T cells at baseline compared to pts with PD (16/60) (mean 43% vs. 30%, P = 0.0484). The frequencies of Bim+ T cells decreased significantly after the first 3 months of treatment in responders compared with progressors (mean -16% vs. + 40% P = 0.0111). High baseline sPD-L1 were associated with progression on anti-PD1 therapy (mean 2.8 ng/mL vs. 0.7 ng/mL, p = 0.07, n = 13) and the levels increased by the first tumor assessment in patients resistant to anti-PD-1. Conclusions: Measurements of Bim and sPD-L1 levels may help to select patients who are likely to benefit from anti-PD1 monotherapy versus combinatorial strategies, and provide a new non-invasive way to monitor response to anti-PD-1 blockade. A larger validation study is underway.

11008 Background: SARC028 is the first multicenter Phase II study of P monotherapy in patients (pts) with STS and BS. Designed to detect clinical efficacy signals in multiple histologies, the study collected blood & tissue samples on all pts. We report extended clinical follow-up and in-depth biomarker correlates of response. Methods: The primary endpoint was objective response rate (ORR) by RECIST 1.1. Secondary endpoints were safety, 12 wk progression-free survival (PFS), and overall survival (OS). The STS arm had 10 pts in each of 4 cohorts: undifferentiated pleomorphic sarcoma (UPS), dedifferentiated liposarcoma (DDLPS), synovial sarcoma (SS) and leiomyosarcoma (LMS). The BS arm included 40 pts with osteosarcoma (OS), Ewing sarcoma (ES) or dedifferentiated chondrosarcoma (CS). Pre- and on-P biopsies were required as well as blood at multiple time points. Tumor was assessed for PD-L1 expression (clone 22C3) and immune infiltrates by multi-color IHC (Vectra). Ongoing analyses include circulating cytokine and checkpoint levels and exome (DNA), transcriptome (RNA), and T-cell receptor (TCR) sequencing. Results: 86 pts were enrolled, 80 were evaluable for response. For STS, median follow-up was 14.5 months. The ORR in the overall STS cohort was 18% and the 12-wk PFS 55% [95% CI, 42-71]). Clinical activity was variable by histologic subtype with 40% ORR in UPS (1 CR and 3PR out of 10 evaluable pts), 2 PR/10 were seen in DDLPS, 1PR/10 in SS and 0/10 in LMS. For BS, median follow-up was 12.3 months (ORR 5%; 12-wk PFS 28% [95% CI, 14-41]), with 1PR/22 OS, 1PR/5 CS and 0/13 ES. 70 pre-P tissues were analyzed (11 excluded for insufficiency), with PD-L1+ in 3/70 (4%); all 3 were UPS. Of the 2 evaluable pts, 1 had CR and 1 PR. 2 OS were PD-L1+ on multi-color IHC, 1 had PR. All PD-L1+ samples had CD8+ T-cell infiltration. There were no post-P PD-L1+ samples. Conclusions: P has clinical activity in UPS and LPS, and expansion cohorts in those subtypes are planned. Pre-treatment PD-L1 expression was infrequent, but correlated with T-cell infiltration and response in UPS & OS. Ongoing biomarker analyses that may guide combination strategies are ongoing and will be presented at the meeting. Clinical trial information: NCT02301039.

e21057 Background: BRAF, NRAS, CDKN2A and P53 mutations are commonly observed pathogenic mutations in cutaneous melanoma. The influence of mutations such as BRAF, NRAS, CDKN2A and P53 on treatment response in the PD1 inhibitor era has not been well defined. Methods: This study included patients with melanoma with a cutaneous or unknown primary. All patients had genomic profiling with the Mayo Clinic 50-gene solid tumor mutation panel. Treatment response to first line immunotherapy with PD1, CTLA-4, or combination PD1/CTLA-4 inhibitors were assessed by response rate and time-to-progression (TTP) rate at 12 months. Each patient outcome was stratified by non-mutually exclusive gene mutation status into BRAF, NRAS, P53, CDKN2A, or quadruple negative (N4) groups. Results: Genomic profiling was performed on 208 patients, of whom 102 received first line immunotherapy. Most patients received a PD1 inhibitor (n = 62), followed by CTLA-4 inhibitor (n = 34), and combination therapy (n = 6). A trend towards improved outcomes was observed in CDKN2A and BRAF mutated patients with worse outcomes noted in P53, N4, and NRAS patients. The percent without progression at 12 months were BRAF 52.2%, CDKN2A 58.2%, NRAS 30.5%, P53 37.7%, and N4 26.7% (see table below). Response rates were BRAF 46.4%, CDKN2A 38.5%, NRAS 22.2%, P53 40.0%, and N4 33.3%. Conclusions: There is a trend towards improved outcomes with immunotherapy in BRAF and CDKN2A mutated patients while P53, NRAS and N4 patients have inferior outcomes. [Table: see text]

e21054 Background: Up to 50% of patients undergoing resection for advanced melanoma experience recurrence. Identification of preoperative prognostic biomarkers is needed to ascertain risk of relapse and guide postoperative management. Lactate dehydrogenase (LDH) represents a strong prognostic factor in unresectable metastatic (stage IV) melanoma, but its relevance in patients with resected stage III or IV disease remains unknown. Methods: We retrospectively analyzed data from patients with stage III and IV melanoma who had undergone complete resection of disease and received follow-up treatment at Mayo Clinic, Rochester between January 1, 2000 and January 31, 2012. Clinical data were collected from electronic records. Survival data were estimated using the Kaplan-Meier method. Associations of preoperative LDH with time to relapse and death were evaluated using Cox proportional hazards regression models and summarized with hazard ratios and 95% confidence intervals. Results: A total of 154 subjects with resectable stage III or IV melanoma were included in the study. Median age at the time of resection was 58; 54 (35.1%) were female. One-hundred sixteen (75.3%) patients were classified as stage III and 38 (24.7%) stage IV. Adjuvant systemic treatment was administered in 75 (48.7%) patients and adjuvant radiation in 32 (20.7%). Median duration of follow-up was 4.0 years. Sixteen (10.3%) patients had preoperative LDH above the upper limit of normal. Each 50-unit increase in LDH was associated with a 15% increased risk of relapse (HR 1.15; p = 0.040) and 23% increased risk of death (HR 1.23; p = 0.001). After adjusting for age, gender, stage, number of sites, adjuvant systemic treatment, and adjuvant radiation, preoperative LDH remained associated with time to death (HR 1.25; p = 0.002). Preoperative LDH greater than the upper limit of normal was associated with increased hazard of death, both with univariate (HR 2.44; p = 0.005) and multivariate (HR 2.17; p = 0.017) analyses. Conclusions: This study supports the role of elevated preoperative LDH as a predictor of inferior outcomes in patients with advanced melanoma. Further study to correlate LDH to outcomes in the era of adjuvant immunotherapy is required.

7516 Background: PCNSL is a diffuse large B cell lymphoma confined to the CNS. Pomalidomide (POM) is a novel immunomodulatory agent with excellent CNS penetration (~40%) based on CNS PK analysis in rats and pre-clinical therapeutic activity against CNS lymphoma. Methods: A Phase I clinical trial was undertaken to determine the maximal tolerated dose (MTD) of POM, safety profile and overall response rate (ORR). Treatment consists of POM daily for 21 days every 28 days in combination with dexamethasone 40 mg PO weekly for two cycles followed by POM alone in subsequent cycles until progression or intolerance. 4 dose escalation levels of POM (3mg, 5mg, 7mg, and 10 mg) were planned. Thromboprophylaxis with oral anticoagulant or aspirin was required. MTD determination has been completed and expansion of the MTD cohort is ongoing. Therapeutic responses were evaluated per the international PCNSL collaborative group (IPCG) criteria after 2 cycles of treatment. The trial is registered with ClinicalTrials.gov (#NCT01722305). Results: 21 of 25 patients accrued were eligible for assessment. The MTD was determined to be 5 mg qd for 21 days every 28 days. Two DLTs were seen at dose level 3 (Grade 3 dyspnea and grade 4 thrombocytopenia). One DLT was seen in the expanded MTD cohort (Grade 4 neutropenia and lymphocytopenia). ORR for the study (9/21) was 43% (95% CI- 22%, 66%) with 4 CR, 1 CRu and 4 PR. 3 responders completed 2, 4, and 6 cycles before progression. 6 responders have completed 4, 5, 6, 10, 12, and 32 cycles and remain on treatment. ORR for the MTD dose level was (5/12) 42% (95% CI- 15%, 72%) with 3 CR and 2 PR. 2 patients had stable disease (SD). Pseudo-progression was seen in 1 patient. Overall, grade 3/4 toxicity was hematologic (neutropenia, anemia, and thrombocytopenia) in 38.1% and non-hematologic in 33.3% (fatigue, pneumonia, sepsis, syncope, dyspnea, hypoxia, respiratory failure and maculo-papular rash). Percent CSF/blood ratio of POM was determined to be 19% in 1 patient. Conclusions: Pomalidomide treatment is feasible with therapeutic activity against relapsed/refractory PCNSL and should be further developed. Clinical trial information: NCT01722305.