McGreivy, Jesse

4540 Background: Patients w/ locally advanced or metastatic urothelial carcinoma (UCC) have a poor prognosis. Prior to atezolizumab’s approval, there were no approved treatments (txs) for pts who progressed after chemotherapy. Even w/ immune checkpoint inhibitors, most pts require additional txs. FGFR3 is frequently overexpressed in UCC and 15-20% of pts w/ advanced disease have tumors w/ FGFR3 gene mutations or fusions. B-701 (formerly R3Mab) is a fully human monoclonal antibody against FGFR3 that blocks activation of the wildtype and genetically activated receptor. NCT02401542 is a phase (ph) 1b/2 study designed to evaluate the safety and efficacy of B-701 plus docetaxel (D) in advanced UCC pts. Methods: The study has a lead-in (n=20 pts) and a randomized ph (n=201). Eligible pts: Stage IV UCC, relapsed/refractory to 1 or 2 prior chemotherapy regimens not including taxanes with ECOG 0-1. Txs: B-701 at 25 mg/kg q3w (+ loading dose on C1D8) and D at 75 mg/m2 q3w. Efficacy assessed by RECIST 1.1. Primary obj: PFS and safety. Secondary obj: overall response rate (ORR); duration of response (DOR); disease control rate (DCR); overall survival (OS). Exploratory obj: association of FGFR3 status w/ efficacy and AEs. Results: As of 20 Jan 2017, 19 pts enrolled to lead-in ph w/median age 66 yrs, ECOG 1 58%, Hgb <10 gm/dL 5%, liver mets 26% and ≥ 2 prior regimens 63%. 17 evaluable for PFS/ORR. 5 pts w/ FGFR3 mut or TACC3-fus. Gr ≥3 AEs occurring in ≥2 pts: decreased neutrophils (26.3%), neutropenia (10.5%), decreased WBCs (10.5%). 2 pts had D dose reductions and 1 pt discontinued tx due to AE (disseminated intravascular coagulation). Conclusions: Preliminary results show that B-701 combines safely and effectively with D in UCC, with the combination being well tolerated and showing promising ORR and PFS in pts w/ FGFR3 mut/fus. The protocol has been amended to add Cohorts 2 (B-701+D) and 3 (B-701) (n=20 pts/cohort) for pts w/ FGFR3 mut/fus+ tumors only. Clinical trial information: NCT02401542. [Table: see text]

LBA7008 Background: Treatment options for CLL/ SLL patients (pts) who fail chemoimmunotherapy are limited. We report interim results from a phase III randomized study of ibrutinib (ibr), a first in class covalent BTK inhibitor, vs ofatumumab (ofa) in R/R CLL/SLL. The Data Monitoring Committee recommended this analysis be considered final, based on meeting the primary and a key secondary endpoint. Methods: R/R CLL/SLL pts who failed ≥1 therapy received 420 mg oral ibr daily until progression or IV ofa 300/2000mg for 12 doses. Primary endpoint was progression-free survival (PFS) assessed by an independent review committee (IRC). Secondary endpoints included overall survival (OS), IRC assessed overall response rate (ORR) and safety. Results: Of 391 pts enrolled (median age 67 years; 40% ≥70 years; 57% Rai stage III/IV disease; 30% del 17p), 195 were randomized to ibr and 196 to ofa. Ibr pts had median 3 prior therapies vs 2 for ofa. Median follow-up was 9.4 months (m). Ibr significantly lengthened PFS (median not reached vs 8.1 m; HR 0.215, CI 0.146–0.317, p<0.0001; 78.5% risk reduction), and significantly improved OS (median not reached; HR 0.434, CI 0.238–0.789, p=0.0049) compared with ofa. ORR was 42.6 vs 4.1% (p<0.0001) and ORR+PR with lymphocytosis was 62.6 vs 4.1% for ibr vs ofa. Similar effects were seen in del17p and purine analog refractory subsets. In each arm 2 pts had confirmed Richter’s transformation. Most frequent adverse events (AE) for ibr vs ofa were diarrhea (47.7 vs 17.8%) fatigue (27.7 vs 29.8%), and nausea (26.2 vs 18.3%). Atrial fibrillation was more frequent with ibr (5.1 vs 0.5%). Major hemorrhages were reported in 1.0 vs 1.6% for ibr vs ofa. Drug discontinuation due to AE was 4.1 vs 3.6% for ibr vs ofa. 86% of ibr pts were continuing treatment. 57 pts randomized to ofa with confirmed PD had initiated ibr at cross-over. Conclusions: Compared with ofa, ibr significantly improved PFS, OS and ORR in pts with R/R CLL/SLL. The safety profile was comparable with that previously reported (Byrd NEJM 2013). These results support ibr as a beneficial therapy for R/R CLL patients irrespective of del 17p or purine analog refractory disease. Clinical trial information: NCT01578707.