Patil, Sujata

5017 Background: HDCT/ASCT represents a curative salvage treatment for patients with GCT but is rarely used for other solid tumors. Patients undergoing HDCT/ASCT for hematologic neoplasms require revaccination for their childhood immunizations. Whether this is necessary in patients with GCT is unknown. Methods: In this prospective longitudinal study, patients with GCT undergoing HDCT-ASCT from 11/2010 to 5/2018 had serologies for Measles, Mumps, Rubella, Diphtheria, Tetanus, Polio, and Varicella Zoster measured before HDCT and at 3, 6, and in a subset, 12+ months after the last HDCT with results at these timepoints compared using descriptive statistics. In addition, titer levels at ≥6 months post-transplant were matched 1:1 for age and gender with HL patients who underwent HDCT/ASCT during the same time period. Immunity was compared between cohorts using the Cochran-Mantel-Haenszel test. Results: Of 80 patients with GCT (median age 30, 84% nonseminoma), 91% received 3 sequential transplants and 68 had repeat titers at ≥6 months. Immunity at baseline was >95% for Diphtheria, Tetanus and Polio and 89% for Varicella Zoster but lower for Measles (74%), Mumps (85%), and Rubella (83%) (Table). Compared to baseline, proportional immunity for all infections was similar at 3, 6, and 12 months post-transplant in the GCT population (≥6 months shown in Table). Matching resulted in 58 GCT-HL pairs. One-year immunity was numerically lower for most infections in the HL vs. GCT patients and significantly decreased for Measles and Rubella (Table). Conclusions: To our knowledge, this is the first study to assess vaccine titers following HDCT/ASCT for GCT. We demonstrate that HDCT/ASCT does not result in loss of immunity to childhood vaccines and that GCT patients retain protective titers more frequently than those with HL. However, 15-31% of GCT patients lack MMR immunity at baseline and at 1-year post-ASCT. Therefore, we recommend checking MMR titers at 1-year post-ASCT with revaccination of those lacking immunity. Titer evaluation and revaccination is not necessary for other childhood immunizations.[Table: see text]

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.