While HIV-1 reverse transcriptase (RT) mutations of M to V at position 184 are commonly observed in the clinic, the double mutation of 65R+74V is rarely seen. It has been demonstrated that rapid R→K reversion occurs at RT codon 65 during replication of HIV-1 in human peripheral blood mononuclear cells containing 65R+74V mutations and that processivity of the RT is reduced relative to wild type. However, clinical studies show that M184V can be detected after several months of therapy interruption, suggesting more effective processivity. Herein, the in vitro RT processivity of genetically engineered M184V and double mutant 65R+74V was compared. Virion-associated RTs of WT pNL4-3, K65R, L74V, M184V and 65R+74V were used to perform RT processivity assays in the presence of trap, poly(rC)-oligo(dG). Both RTs with 184V and 65R+74V mutations exhibited similar processivity when compared with each other and a significantly decreased processivity as compared to WT RT. Both mutant RTs synthesized shorter cDNA molecules (37–42 nt) relative to WT RT, which made longer (65–70 nt) cDNA molecules. Since these surprising biochemical results cannot explain the clinical phenotype, a hypothesis is presented to explain the discrepancy and suggest new approaches for future testing.

Introduction:The depth and durability of response to ibrutinib in patients (pts) with relapsed/refractory (R/R) MCL and high risk CLL is limited. TGR-1202 is a novel oral PI3K-δ specific inhibitor designed to have less toxicity than other PI3K inhibitors. We hypothesized that combined PI3K/BTK blockade with TGR-1202 and ibrutinib would be tolerable and efficacious in R/R MCL and CLL.Methods: This is an ongoing phase I/Ib investigator-initiated trial with primary endpoints of recommended phase 2 dose (RP2D) and safety/ tolerability. Secondary endpoints include ORR and CR rates, PFS, and OS. Pts receive daily ibrutinib (560 mg MCL, 420 mg CLL) and TGR-1202. TGR-1202 doses from 400 mg to 800 mg were evaluated in a standard 3 + 3 design. Pts continue both drugs until progression or unacceptable toxicity. Eligibility criteria: ≥1 prior therapy, ECOG PS ≤2, and adequate hematologic and organ function. Prior PI3K/BTK inhibitors were allowed. Lugano Classification (MCL) and IW-CLL criteria were used to evaluate efficacy.Results: Thirty-three pts have enrolled on study, including 15 MCL and 18 CLL pts. The median age at enrollment was 67 yrs. (range 48-83).The median number of prior therapies was 3 for MCL (range 2-5, including 4 with prior autoSCT) and 2 for CLL (range 1-6). In CLL pts, del(17p) was present in 4/17 (24%), del (11q) in 7/17 (41%), and unmutated IGHV in 11/17 (65%).In phase I, no DLTs occurred in either arm, and the RP2D of TGR-1202 for both MCL and CLL was 800 mg. In a combined safety analysis of both arms (n = 33), hematologic toxicity included neutropenia (36%, 12% gr3/4), thrombocytopenia (21%, 3% gr3), and anemia (21%, 3% gr3). All grade non-hematologic toxicities in >10% of pts included: nausea (36%, all gr1/2), fatigue (33%, all gr1/2), diarrhea (33%, all gr1/2), and dizziness (24%, all gr1). Transaminitis (all gr1) was observed in 7/33 (21%) pts. SAEs included 2 pts each with: gr3/4 lipase elevation, gr3 hypophosphatemia, CNS aspergillus infection, and atrial fibrillation, and 1 pt each with: adrenal insufficiency (gr3), influenza A infection (gr4), C. difficile infection (gr4), and sudden death of uncertain cause. Two pts had dose reduction of TGR-1202 (dizziness, nausea), and 3 pts had dose-reduction of ibrutinib (atrial fibrillation, palpitations, vitreous hemorrhage). In MCL, with a median time on study of 10.9 mo. (range 1.1-19.8 mo.), the ORR is 85% (11/13), including 1 CR. In CLL, with a median time on study of 11 mo. (range 0.1-23.5 mo.), the ORR is 89% (16/ 18), with 1 pt achieving iwCLL CR, and 1 pt with radiographic CR.The 1 year PFS and OS for MCL are 37% and 52%, and for CLL both are 94%. tested for GBV-C RNA by RT-PCR, and those with RNA concentrations <5,000 genome equivalents/ml were confirmed using RT-PCR again. Unconditional logistic regression model was used to estimate odds ratio (ORs) and 95% confidence intervals (CI), adjusted for age and sex.Results: The mean age of cases was 61 years, and 58.2% were male, while the mean age of controls was 63 years, and 51.1% were male; 78...