Mayer, Jiřı́

LBA7006 Background: PAC is a potent JAK2 inhibitor without significant JAK1 inhibition with minimal myelosuppression in early-phase studies in MF. Methods: The efficacy and safety of daily oral PAC was compared to BAT (2:1 randomization stratified for risk and platelet count). The 10 endpoint was the proportion of ITT patients (pts) achieving ≥ 35% spleen volume reduction (SVR) at week (wk) 24 by centrally reviewed MRI or CT. Secondary endpoints included the proportion achieving ≥ 50% reduction in total symptom score (TSS) at wk 24 using the MPN Symptom Assessment Form. Results: Patients:327 were enrolled (PAC:220, BAT:107), 62% with 10 MF. Median time from diagnosis was 1.12 years (PAC 0.99, BAT 1.60): 32% and 15% had a platelet counts < 100,000/µL or <50,000/ µL; 75% were JAK2V617F positive. Efficacy: The median duration of treatment was 16.2 months PAC and 5.9 months BAT. Sixty-two percent of BAT patients received active disease directed therapy. The SVR rates at week 24 were 19.1% for PAC vs. 4.7% for BAT (p=0.0003) in ITT and 25% vs. 5.9% (p=0.0001) in the evaluable population. 79% of BAT patients crossed over to PAC; 21% had achieved a >35% reduction in spleen volume at data cutoff. TSS composite V1 + V2 response rates were 24.5%for PAC vs. 6.5% for BAT (p<0.0001) by ITT, and were 40.9% vs. 9.9% in evaluable pts (p<0.0001). Efficacy with baseline cytopenias: In pts with <100,000 and <50,000 platelets/μ/L, the SVR rates were 16.7% for PAC vs. 0% for BAT (p=0.009), and 22.9% vs. 0% (p=0.045) by ITT and 23.5% vs. 0% (p=0.007) and 33.3% vs. 0% (p=0.037) in evaluable pts. In RBC transfusion dependent pts, 25.7% of PAC pts became RBC independent vs. 0% of BAT pts (p=0.043). Safety: The most common adverse events (AE) for PAC were diarrhea, nausea, and vomiting; (grade 3 were <5%, <1%, <1% respectively). Hematologic AEs were similar between PAC and BAT. Conclusions: This study demonstrated PAC was well tolerated and induced significant and sustained SVR and symptom control even in patients with severe thrombocytopenia. PAC therapy resulted in RBC transfusion independence in a significant proportion of pts. Clinical trial information: NCT01773187.

LBA7005 Background: The phase III HELIOS study evaluated the first-in-class, oral covalent BTK inhibitor ibrutinib in combination with BR (BR+ibr) vs BR plus placebo (BR+plb) in patients (pts) with previously treated CLL/SLL. The preplanned interim analysis reported here showed that the primary end point was met, upon which the IDMC recommended unblinding the study. Methods: Pts received BR ( ≤ 6 cycles) and were randomized 1:1 to ibr (420 mg daily) or plb. Purine analog refractoriness was a stratification factor. Pts with del17p ( > 20% of cells) were excluded. Primary end point was independent review committee (IRC)-assessed progression-free survival (PFS). Secondary end points included overall survival (OS) and overall response rate (ORR) per IRC. Results: 578 pts were randomized (289 per arm); median age 64 yrs; 38% Rai Stage III/IV; median 2 prior therapies. 6 cycles of BR were completed in 83% and 78% of pts in the ibr and plb arms, respectively. At a median follow-up of 17.2 months, IRC-assessed PFS was significantly longer with BR+ibr vs BR+plb (median not reached vs 13.3 months; HR: 0.203, 95% CI: 0.150-0.276, P< 0.0001); PFS results were consistent across high-risk subgroups. ORR and CR/CRi rates were 82.7% vs 67.8% (P< 0.0001) and 10.4% vs 2.8%. Median OS was not reached. 90 pts (31%) in the BR+plb arm with confirmed PD crossed over to receive ibr, as permitted per the protocol. Incidence of most AEs was similar between arms. The most common all-grade AEs with BR+ibr and BR+plb were neutropenia (58.2% vs 54.7%) and nausea (36.9% vs 35.2%); most common grade 3/4 AEs were neutropenia (53.7% vs 50.5%) and thrombocytopenia (15.0% each arm). Rates of grade 3/4 atrial fibrillation were 2.8% and 0.7%, and major hemorrhage were 2.1% and 1.7%. Fatigue (FACIT-Fatigue) was improved with BR+ibr vs BR+plb. Conclusions: The addition of ibr to BR reduced the risk of progression or death by 80% compared with BR+plb. ORR was also significantly improved. Safety of BR+ibr was consistent with the known profiles for BR and ibr. The data further support ibr as an important treatment option for pts with previously treated CLL/SLL. Clinical trial information: EudraCT No. 2012-000600-15; UTN No. U1111-1135-3745.