Appleman, Leonard J.

364 Background: Flavopiridol + FOLFOX showed activity in refractory GCT pts in a phase I trial (Rathkopf, Clin Cancer Res, 2009). This phase II study assessed the efficacy of this regimen in refractory GCT and the necessity of including 5-FU/LV. Methods: Previously treated pts with progressive GCT were eligible if they had received or were not candidates for high-dose chemotherapy (HDCT). Pts on Arm A received flavopiridol 70mg/m2 plus oxaliplatin 85mg/m2. Arm B (flavopiridol + FOLFOX) tested identical doses of flavopiridol and oxaliplatin plus 5-FU (400mg/m2 bolus, then 1800mg/m2 over 48 hours) and LV 400mg/m2. Treatment was every 2 weeks in 6-week cycles. The primary endpoint was response rate (RR) by RECIST. An identical Simon 2-stage design was used for each arm to differentiate between a RR ≥40% vs. ≤20%, with arm B opening only if arm A was ineffective. With ≥3 responses among the first 12 pts, another 13 pts would be enrolled with responses in ≥8/25 pts needed to show efficacy. Tumor biopsies pre-, during, and post-treatment were assessed by IHC for p53, p21, and cleaved caspase-3. Results: Of 36 pts (7 arm A, 29 arm B), 33 had nonseminoma. Primary site was testis in 27 and mediastinum in 7; 22 pts had received prior HDCT and 13 had LR (>2 years), including 2 on arm A and 11 on arm B. Arm A closed early after 0/7 pts responded (2 SD). Of 25 evaluable pts on arm B, 6 achieved a PR, 9 had SD, and 10 had PD. Notably, 5/10 evaluable LR pts on Arm B had a PR, including 1 pathologic CR, 1 PR-negative markers who received radiation (RT) to a residual bone metastasis, and 1 PR-positive markers who received RT to a residual nodal mass. These 3 pts remain disease-free ≥19 months (m) post-chemotherapy and ≥17m post-RT or surgery. Median PFS and OS were 2.3m and 7.3m for all pts and 3.2m and 11.2m for arm B pts. There was 1 treatment-related death due to sepsis. Conclusions: Although neither arm met the prespecified endpoint, flavopiridol plus FOLFOX (arm B) was particularly active in LR pts, with a 50% overall RR, including several durable responses. Further study of FOLFOX with or without flavopiridol is warranted in LR pts. Correlative data will be presented. Clinical trial information: NCT00957905.

617 Background: Over the past decade, seven agents were approved for metastatic renal cell carcinoma (mRCC) leading to a rapidly evolving clinical landscape. Clinical trials addressing treatment efficacy, sequencing, and other questions may continue to impact management decisions. Furthermore, our prior retrospective experience indicates a significant proportion of pts may not receive systemic therapy in the first year after diagnosis with metastatic disease. This analysis describes contemporary patterns of care in the first 109 real world pts enrolled in a multicenter, prospective, observational registry. Methods: MaRCC Registry will enroll 500 pts from up to 60 US academic (ACAD) and community (COMM) sites with ~2 years of recruitment and ≥ 3 years of follow-up. Key inclusion criteria are age ≥ 18 years and diagnosis of mRCC with no prior systemic therapy (STx) for mRCC at study entry. Pts currently not on STx but who are being observed are permitted. Key endpoints include descriptive characteristics of treatments (e.g. treatment agents, sequence, duration, reasons for therapy choice and discontinuation), treatment effectiveness (e.g. overall response rate, progression free survival, overall survival), quality of life (PROs), medication adherence, and health resource utilization. Results: At data cutoff, 105 pts have been accrued with known STx status; median age 64 (Q1-3 range, 56-70); 66% male; 75% ACAD; 87% clear cell histology; and 31% stage IV at diagnosis. Initial management strategies are shown in the table. The initial management decision after accrual was to defer systemic therapy (Def STx) in 40% (N=44). In ACAD and COMM sites, Def STx percentages were 38% and 48% respectively. Baseline demographics and clinical characteristics were not notably different between Def STx pts and those treated with STx. Conclusions: In our prospective registry, we have identified a large percentage of pts who initially received Def STx. In the context of contemporary pts undergoing investigational and standard of care STx, we will describe the management and outcomes of the Def STx population. [Table: see text]

563 Background: Clinical trials mRCC pts are different from real world pts, resulting in bias in the literature. The MaRCC Registry is designed to survey questions not asked in tri als, such as why physicians make certain management decisions. This analysis describes reasons for physician treatment (tx) selection in the first 109 real world pts enrolled in a multicenter, prospective, observational registry. Methods: MaRCC Registry will enroll 500 pts from up to 60 US academic (ACAD) and community (COMM) sites with ~2 years of recruitment and ≥ 3 years of follow-up. Key inclusion criteria are age ≥ 18 years and diagnosis of mRCC with no prior systemic therapy (STx) for mRCC at study entry. Pts currently not on STx but who are being observed are permitted. Key endpoints include descriptive characteristics of txs, tx and patient outcomes, medication adherence, and health resource utilization. Results: At data cutoff, 105 pts have been accrued with known STx status; median age 64 (Q1-3 range, 56-70); 66% male; 75% ACAD; 87% clear cell histology; and 31% stage IV at diagnosis. Initial management decision was: 40% deferred systemic therapy (DSTx), 22% pazopanib, 18% clinical trial, 10% sunitinib, and 6% other. Among STx pts (N = 61), the most common categories for therapy choice as selected by providers were likelihood of clinical benefit (41%) followed by pt characteristics (30%). Within the clinical benefit category, the most common reason was OS/PFS (31%). Within the pt characteristic category the most common reasons included performance status/frailty (12%) or prognostic factors (12%). Common reasons for DSTx pts (N = 44) were active surveillance (AS) with disease present (39%), AS without disease present following a procedure (11%), or local therapy (7%). ACAD sites had higher percentages of pts with DSTx undergoing AS with disease present and local therapy. Conclusions: This is the first report describing factors driving physician decision making in management of mRCC. Management choices are not captured in other prospective or retrospective studies. Early experience suggests that clinical benefit and pt characteristics were common reasons for initial STx. Side effect profile rarely determined initial STx selection.

Abstract Purpose: High-dose aldesleukin (HD IL2) received FDA approval for the treatment of metastatic renal cell carcinoma (MRCC) in 1992, producing a 14% objective response rate (ORR) and durable remissions. Retrospective studies suggested that clinical and pathologic features could predict for benefit. The Cytokine Working Group conducted this prospective trial to validate proposed predictive markers of response to HD IL2. Experimental Design: Standard HD IL2 was administered to prospectively evaluate whether the ORR of patients with mRCC with “good” predictive pathologic features based on an “integrated selection” model [ISM (e.g., clear-cell histology subclassification and carbonic anhydrase-9 (CA-9) IHC staining] was significantly higher than the ORR of a historical, unselected population. Archived tumor was collected for pathologic analysis including tumor programmed death-ligand 1 (PD-L1) expression. Results: One hundred and twenty eligible patients were enrolled between June 11 and September 7; 70% were Memorial Sloan Kettering Cancer Center (New York, NY) intermediate risk, 96% had clear cell RCC, and 99% had prior nephrectomy. The independently assessed ORR was 25% (30/120, 95% CI, 17.5%–33.7%, P = 0.0014; 3 complete responses, 27 partial responses) and was higher than a historical ORR. Thirteen patients (11%) remained progression free at 3 years and the median overall survival was 42.8 months. ORR was not statistically different by ISM classification (“good-risk” 23% vs. “poor-risk” 30%; P = 0.39). ORR was positively associated with tumor PD-L1 expression (P = 0.01) by IHC. Conclusions: In this prospective, biomarker validation study, HD IL2 produced durable remissions and prolonged survival in both “good” and “poor-risk” patients. The proposed ISM was unable to improve the selection criteria. Novel markers (e.g., tumor PD L1 expression) appeared useful, but require independent validation. Clin Cancer Res; 21(3); 561–8. ©2014 AACR.