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Purpose: Indolent non-Hodgkin lymphoma (iNHL) remains largely incurable and often requires multiple lines of treatment after becoming refractory to standard therapies. Duvelisib was approved by the Food and Drug Administration for relapsed or refractory (RR) chronic lymphocytic leukemia or small lymphocytic lymphoma (SLL) and RR follicular lymphoma (FL) after two or more prior systemic therapies. On the basis of the activity of duvelisib, a first-in-class oral dual inhibitor of phosphoinositide 3-kinase-δ,-γ, in RR iNHL in a phase I study, the safety and efficacy of duvelisib monotherapy was evaluated in iNHL refractory to rituximab and either chemotherapy or radioimmunotherapy., Patients and Methods: Eligible patients had measurable iNHL (FL, SLL, or marginal zone B-cell lymphoma) double refractory to rituximab (monotherapy or in combination) and to either chemotherapy or radioimmunotherapy. All were treated with duvelisib 25 mg orally twice daily in 28-day cycles until progression, unacceptable toxicity, or death. The primary end point was overall response rate (ORR) using the revised International Working Group criteria for malignant lymphoma., Results: This open-label, global phase II trial enrolled 129 patients (median age, 65 years; median of three prior lines of therapy) with an ORR of 47.3% (SLL, 67.9%; FL, 42.2%; MZL, 38.9%). The estimated median duration of response was 10 months, and the estimated median progression-free survival was 9.5 months. The most frequent any-grade treatment-emergent adverse events (TEAEs) were diarrhea (48.8%), nausea (29.5%), neutropenia (28.7%), fatigue (27.9%), and cough (27.1%). Among the 88.4% of patients with at least one grade 3 or greater TEAE, the most common TEAEs were neutropenia (24.8%), diarrhea (14.7%), anemia (14.7%), and thrombocytopenia (11.6%)., Conclusion: In the DYNAMO study, oral duvelisib monotherapy demonstrated clinically meaningful activity and a manageable safety profile in heavily pretreated, double-refractory iNHL, consistent with previous observations. Duvelisib may provide a new oral treatment option for this patient population of which many are elderly and in need of additional therapies.

Duvelisib (also known as IPI-145) is an oral, dual inhibitor of phosphatidylinositol 3-kinase δ and γ (PI3K-δ,γ) being developed for treatment of hematologic malignancies. PI3K-δ,γ signaling can promote B-cell proliferation and survival in clonal B-cell malignancies, such as chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). In a phase 1 study, duvelisib showed clinically meaningful activity and acceptable safety in CLL/SLL patients. We report here the results of DUO, a global phase 3 randomized study of duvelisib vs ofatumumab monotherapy for patients with relapsed or refractory (RR) CLL/SLL. Patients were randomized 1:1 to oral duvelisib 25 mg twice daily (n = 160) or ofatumumab IV (n = 159). The study met the primary study end point by significantly improving progression-free survival per independent review committee assessment compared with ofatumumab for all patients (median, 13.3 months vs 9.9 months; hazard ratio [HR] = 0.52; P < .0001), including those with high-risk chromosome 17p13.1 deletions [del(17p)] and/or TP53 mutations (HR = 0.40; P = .0002). The overall response rate was significantly higher with duvelisib (74% vs 45%; P < .0001) regardless of del(17p) status. The most common adverse events were diarrhea, neutropenia, pyrexia, nausea, anemia, and cough on the duvelisib arm, and neutropenia and infusion reactions on the ofatumumab arm. The DUO trial data support duvelisib as a potentially effective treatment option for patients with RR CLL/SLL. This trial was registered at www.clinicaltrials.gov as #NCT02004522., (© 2018 by The American Society of Hematology.)

Duvelisib (IPI-145), an oral, dual inhibitor of phosphoinositide-3-kinase (PI3K)-δ and -γ, was evaluated in a Phase 1 study in advanced hematologic malignancies, which included expansion cohorts in relapsed/refractory (RR) chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and treatment-naïve (TN) CLL. Per protocol, TN patients were at least 65 years old or had a del(17p)/TP53 mutation. Duvelisib was administered twice daily (BID) in 28-day cycles at doses of 8-75 mg in RR patients (n = 55) and 25 mg in TN patients (n = 18.) Diarrhea was the most common nonhematologic AE (TN 78%, RR 47%); transaminase elevations the most frequent lab-abnormality AE (TN 33.3%, RR 30.9%); and neutropenia the most common ≥grade 3 AE (RR 44%, TN 33%). The overall response rates were 56.4% for RR patients (1.8% CR, 54.5% PR) and 83.3% for TN patients (all PRs); median response duration was 21.0 months in RR patients but was not reached for TN patients. Based upon phase 1 efficacy, pharmacodynamics, and safety, duvelisib 25 mg BID was selected for further investigation in a phase 3 study in RR CLL/SLL., (© 2018 Wiley Periodicals, Inc.)

Duvelisib (IPI-145) is an oral dual inhibitor of phosphoinositide-3-kinase (PI3K)-δ and -γ in clinical development for the treatment of hematologic malignancies, including indolent non-Hodgkin lymphoma (iNHL). In a Phase 1, open-label study to determine the maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, clinical activity, and safety of duvelisib monotherapy in patients with advanced hematologic malignancies, duvelisib was administered at eight dose levels (8-100 mg BID) in a dose-escalation phase (n = 31 evaluable patients). Two dose-limiting toxicities (DLTs), Grade 3 transaminase elevations and Grade 3 rash, occurred at 100 mg BID, and the MTD was determined to be 75 mg BID. Across all doses, 58.1% of iNHL patients had a response (19.4% complete, 35.5% partial, and 3.2% minor); median time to response was 1.84 months and duration of response was 16.9 months. Median progression-free survival was 14.7 months, and the probability of overall survival at 24 months was 71.7%. Severe (Grade ≥ 3) adverse events included elevated liver enzymes (38.7%), diarrhea (25.8%), and neutropenia (29.0%). Three patients, all in the 75 mg BID cohort, experienced fatal AEs: E. coli sepsis, acute respiratory failure, and fungal pneumonia. No iNHL patients experienced Pneumocystis pneumonia. Duvelisib demonstrated favorable clinical activity and an acceptable safety profile in these high-risk, heavily pretreated, relapsed/refractory iNHL patients, with 25 mg BID selected for further clinical development., (© 2018 The Authors. American Journal of Hematology published by Wiley Periodicals, Inc.)

Duvelisib (IPI-145) is an oral inhibitor of phosphatidylinositol 3-kinase (PI3K)-δ/γ isoforms currently in clinical development. PI3K-δ/γ inhibition may directly inhibit malignant T-cell growth, making duvelisib a promising candidate for patients with peripheral (PTCL) or cutaneous (CTCL) T-cell lymphoma. Inhibition of either isoform may also contribute to clinical responses by modulating nonmalignant immune cells. We investigated these dual effects in a TCL cohort from a phase 1, open-label study of duvelisib in patients with relapsed or refractory PTCL (n = 16) and CTCL (n = 19), along with in vitro and in vivo models of TCL. The overall response rates in patients with PTCL and CTCL were 50.0% and 31.6%, respectively ( P = .32). There were 3 complete responses, all among patients with PTCL. Activity was seen across a wide spectrum of subtypes. The most frequently observed grade 3 and 4 adverse events were transaminase increases (40% alanine aminotransferase, 17% aspartate aminotransferase), maculopapular rash (17%), and neutropenia (17%). Responders and nonresponders had markedly different changes in serum cytokine profiles induced by duvelisib. In vitro, duvelisib potently killed 3 of 4 TCL lines with constitutive phospho-AKT (pAKT) vs 0 of 7 lines lacking pAKT ( P = .024) and exceeded cell killing by the PI3K-δ-specific inhibitor idelalisib. Administration of duvelisib to mice engrafted with a PTCL patient-derived xenograft resulted in a shift among tumor-associated macrophages from the immunosuppressive M2-like phenotype to the inflammatory M1-like phenotype. In summary, duvelisib demonstrated promising clinical activity and an acceptable safety profile in relapsed/refractory TCL, as well as preclinical evidence of both tumor cell-autonomous and immune-mediated effects. This trial was registered at www.clinicaltrials.gov as #NCT01476657., (© 2018 by The American Society of Hematology.)

Duvelisib is an oral dual inhibitor of phosphoinositide 3-kinase-δ (PI3K-δ) and PI3K-γ in late-stage clinical development for hematologic malignancy treatment. This phase 1 study evaluated maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics (PD), efficacy, and safety of duvelisib in 210 patients with advanced hematologic malignancies. In the dose escalation phase (n = 31), duvelisib 8 to 100 mg twice daily was administered, with MTD determined as 75 mg twice daily. In the expansion phase (n = 179), patients with indolent non-Hodgkin lymphoma (iNHL), chronic lymphocytic leukemia (CLL), or T-cell lymphoma (TCL) were treated with 25 or 75 mg duvelisib twice daily continuously. Single-dose duvelisib was rapidly absorbed (time to maximum concentration, 1-2 hours), with a half-life of 5.2 to 10.9 hours. PD results showed inhibition of phospho-AKT (S473) in CLL tumor cells following a single dose and near-complete inhibition of CLL proliferation (Ki-67) by cycle 2. Clinical responses were seen across a range of doses and disease subtypes: iNHL overall response rate, 58% (n = 31) with 6 complete responses (CRs); relapsed/refractory CLL, 56% (n = 55) with 1 CR; peripheral TCL, 50% (n = 16) with 3 CR; and cutaneous TCL, 32% (n = 19). Median time to response was ∼1.8 months. Severe (grade ≥3) adverse events occurred in 84% of patients: neutropenia (32%), alanine transaminase increase (20%), aspartate transaminase increase (15%), anemia and thrombocytopenia (each 14%), diarrhea (11%), and pneumonia (10%). These data support further investigation of duvelisib in phase 2 and 3 studies. This trial was registered at clinicaltrials.gov as #NCT01476657., (© 2018 by The American Society of Hematology.)