Roginolisib a Highly Selective Allosteric Modulator of the Phosphoinositide 3-Kinase Delta (PI3Kδ) in Patients with Refractory/Relapsed Follicular Lymphoma
Authors: Carlo-Stella Carmelo , Lahn Michael , Hammett Tracey , Kaur Paramjit , Zorrilla Rebeca , Di Conza Giusy , van der Veen Lars , Pickering Catherine , Santoro Armando 
Published: December 2023

Introduction
PI3Kδ inhibitors are active in patients (pts) with lymphomas, but their clinical development has been hampered by toxicity (Brown et al, Lancet Oncol 2022). Roginolisib (IOA-244) exerts an allosteric modulation of the PI3Kδ C-terminus and functions as a non-ATP competitive PI3Kδ inhibitor, delivering a selective inhibition without off-target effects typically seen with other PI3K inhibitors (Johnson et al, Cancer Res Commun 2023). Using the recommended phase 2 dose (RP2D) of 80 mg QD established in solid tumors patients, patients with refractory/relapsed (r/r) follicular lymphoma (FL) were treated to investigate its safety profile in pts with hematologic malignancies (NCT04328844).
Methods
In Part A of the FiH dose escalation study, roginolisib was investigated at 20 and 80 mg QD in pts with r/r FL. Primary objective: safety of the RP2D established in solid tumor pts. Secondary objectives: PK; PD (e.g., changes in immune cell subsets in peripheral blood); Lugano-based responses; PFS and OS.
Results
In Part A for pts with r/r FL, there were two cohorts: (a) Cohort 1: 20 mg QD daily (4/4; 2 female, 2 male); (b) Cohort 2: 80 mg QD (4/4; 3 female, 1 male). There were no DLT observed and no dose modifications were needed. The mean time on treatment was 1.9 months (20 mg QD) and 4.3 months (80 mg QD), with one patient at the 80 mg receiving Roginolisib for 9 mo. More than 4 prior lines of treatment were in 3/8 pts. Transient (lasting less than 48 hrs) platelet reduction (G3) and AST/ALT elevation (G3) were observed in 2/8 pts, which improved while pts continued without a treatment intervention, such as dose modification or medical treatment with steroids. Lugano-based PRs were observed in 2/4 pts at the 80 mg QD dose and none at the 20 mg QD. At the 80 mg QD dose a third pt had a clinical response manifested by improvement in night sweats and fever, reduction in cervical palpable lymph nodes and relief from chronic pleural effusion. This clinical improvement lasted less than 5 weeks. While Overall Survival (OS) is still ongoing, the median has not been reached in this study and is currently at 14.3 mo. Subsequent to ending Roginolisib treatment, patients received at least one additional therapy (6/8), one patient was able to undergo autologous transplant with a complete metabolic response (CMR). Biomarker evaluation using flow cytometry showed low counts of T regulatory cells (Treg) in peripheral blood in all 8 r/r FL patients compared to solid tumor patients at baseline and throughout the treatment. Myeloid derived suppressor cells in peripheral blood remained unchanged during the course of treatment with Roginolisib.
Conclusions
The safety profile of roginolisib in pts with r/r FL appears to match that in pts with solid malignancies. In contrast to other PI3Kδ inhibitors, roginolisib is highly selective for binding to PI3Kδ, favoring an inactive confirmation of PI3Kd and functions as a non-ATP competitive inhibitor.