Purpose Phosphatidylinositol 3-kinase (PI3K) signaling is critical for the proliferation and survival of malignant B cells. Copanlisib, a pan-class I PI3K inhibitor with predominant activity against PI3K-α and -δ isoforms, has demonstrated efficacy and a manageable safety profile in patients with indolent lymphoma. Patients and Methods In this phase II study, 142 patients with relapsed or refractory indolent lymphoma after two or more lines of therapy were enrolled to receive copanlisib 60 mg intravenously on days 1, 8, and 15 of a 28-day cycle. The primary end point was objective response rate; secondary end points included duration of response, progression-free survival, and overall survival. In addition, safety and gene expression were evaluated. Results Median age was 63 years (range, 25 to 82 years), and patients had received a median of three (range, two to nine) prior regimens. The objective response rate was 59% (84 of 142 patients); 12% of patients achieved a complete response. Median time to response was 53 days. Median duration of response was 22.6 months, median progression-free survival was 11.2 months, and median overall survival had not yet been reached. The most frequent treatment-emergent adverse events were transient hyperglycemia (all grades, 50%; grade 3 or 4, 41%) and transient hypertension (all grades, 30%; grade 3, 24%). Other grade ≥3 events included decreased neutrophil count (24%) and lung infection (15%). High response rates to copanlisib were associated with high expression of PI3K/B-cell receptor signaling pathway genes. Conclusion PI3K-α and -δ inhibition by copanlisib demonstrated significant efficacy and a manageable safety profile in heavily pretreated patients with relapsed or refractory indolent lymphoma.

Acute myeloid leukemia (AML) is a devastating disease, with the majority of patients dying within a year of diagnosis. For patients with relapsed/refractory AML, the prognosis is particularly poor with currently available treatments. Although genetically heterogeneous, AML subtypes share a common differentiation arrest at hematopoietic progenitor stages. Overcoming this differentiation arrest has the potential to improve the long-term survival of patients, as is the case in acute promyelocytic leukemia (APL), which is characterized by a chromosomal translocation involving the retinoic acid receptor alpha gene. Treatment of APL with all-trans retinoic acid (ATRA) induces terminal differentiation and apoptosis of leukemic promyelocytes, resulting in cure rates of over 80%. Unfortunately, similarly efficacious differentiation therapies have, to date, been lacking outside of APL. Inhibition of dihydroorotate dehydrogenase (DHODH), a key enzyme in the de novo pyrimidine synthesis pathway, was recently reported to induce differentiation of diverse AML subtypes. In this report we describe the discovery and characterization of BAY 2402234-a novel, potent, selective and orally bioavailable DHODH inhibitor that shows monotherapy efficacy and differentiation induction across multiple AML subtypes. Herein, we present the preclinical data that led to initiation of a phase I evaluation of this inhibitor in myeloid malignancies.

Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 frequencies, from 15 to 3 breaths/min, before and after beta-adrenergic blockade. We fitted changes of respiratory frequency R-R interval spectral power with a damped oscillator model: frequency-dependent oscillations with a resonant frequency, generated by driving forces and modified by damping influences. beta-Adrenergic blockade enhanced respiratory sinus arrhythmia at all frequencies (at some, fourfold). The damped oscillator model fit experimental data well (39 of 40 ramps; r = 0.86 +/- 0.02). beta-Adrenergic blockade increased respiratory sinus arrhythmia by amplifying respiration-related driving forces (P < 0.05), without altering resonant frequency or damping influences. Both spectral power data and the damped oscillator model indicate that cardiac sympathetic outflow markedly reduces heart period oscillations at all frequencies. This challenges the notion that respiratory sinus arrhythmia is mediated simply by vagal-cardiac nerve activity. These results have important implications for clinical and experimental estimation of human vagal cardiac tone.