Phase 1/1b open-label, dose-escalation study of fruquintinib in patients with advanced solid tumors in the United States

This open-label, phase 1/1b study was conducted to evaluate the safety, tolerability, and pharmacokinetics (PK) of fruquintinib in United States (U.S.) patients to confirm the recommended phase 2 dose (RP2D) established in China. Patients with advanced solid tumors who had progressed on approved systemic therapy, were enrolled into 2 successive dose escalation cohorts, fruquintinib 3 mg (n = 7) or 5 mg (n = 7), orally, once daily (QD), 3 weeks on and 1 week off (3/1) with a 3 + 3 design followed by a dose expansion cohort at the RP2D 5 mg dose (n = 6). PK samples were collected on Days 1, 14, and 21 (Cycle 1). One of 6 dose-limiting toxicity (DLT)-evaluable patients in the 3 mg cohort had a DLT of grade 4 hypertension; there were no DLTs in the 5 mg cohort. The RP2D was confirmed to be 5 mg QD 3/1. All 20 patients experienced a treatment-emergent adverse event; grade ≥ 3 in 5 (71.4%; 3 mg dose) and 12 (92.3%; 5 mg dose) patients. Two patients had a confirmed partial response. After single and multiple doses, median peak plasma concentrations occurred at 2 h post-dose. Steady-state was achieved after 14 days of QD dosing with systemic exposure four-fold higher than that after a single dose. Fruquintinib was well tolerated, and the safety and PK profile at the 5 mg RP2D in U.S. patients with advanced solid tumors was consistent with dose-finding studies in China. Preliminary anticancer activity was observed. This study is registered at Clinicaltrials.gov NCT03251378.

Eganelisib, a First-in-Class PI3Kγ Inhibitor, in Patients with Advanced Solid Tumors: Results of the Phase 1/1b MARIO-1 Trial

PURPOSE

Eganelisib (IPI-549) is a first-in-class, orally administered, highly selective PI3Kγ inhibitor with antitumor activity alone and in combination with programmed cell death protein 1/ligand 1 (PD-1/PD-L1) inhibitors in preclinical studies. This phase 1/1b first-in-human, MAcrophage Reprogramming in Immuno-Oncology-1 (NCT02637531) study evaluated the safety and tolerability of once-daily eganelisib as monotherapy and in combination with nivolumab in patients with solid tumors.

PATIENTS AND METHODS

Dose-escalation cohorts received eganelisib 10-60 mg as monotherapy (n = 39) and 20-40 mg when combined with nivolumab (n = 180). Primary endpoints included incidence of dose-limiting toxicities (DLT) and adverse events (AE).

RESULTS

The most common treatment-related grade ≥3 toxicities with monotherapy were increased alanine aminotransferase (ALT; 18%), aspartate aminotransferase (AST; 18%), and alkaline phosphatase (5%). No DLTs occurred in the first 28 days; however, toxicities meeting DLT criteria (mostly grade 3 reversible hepatic enzyme elevations) occurred with eganelisib 60 mg in later treatment cycles. In combination, the most common treatment-related grade ≥3 toxicities were increased AST (13%) and increased ALT and rash (10%). Treatment-related serious AEs occurred in 5% of monotherapy patients (grade 4 bilirubin and hepatic enzyme increases in one patient each) and 13% in combination (pyrexia, rash, cytokine release syndrome, and infusion-related reaction in ≥2 patients each). Antitumor activity was observed in combination, including patients who had progressed on PD-1/PD-L1 inhibitors.

CONCLUSIONS

On the basis of the observed safety profile, eganelisib doses of 30 and 40 mg once daily in combination with PD-1/PD-L1 inhibitors were chosen for phase 2 study.

Phase 1/1b trial of fruquintinib in patients with advanced solid tumors: Preliminary results of the dose expansion cohorts in refractory metastatic colorectal cancer

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Background: Fruquintinib (F) is a highly selective, novel, oral tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFR) -1, -2, and -3. The phase (Ph) 3 FRESCO study (NCT02314819) that investigated F (5mg daily, 3 weeks (wks) on 1 wk off) showed improved median overall survival in patients (pts) with metastatic colorectal cancer (mCRC) in third line and beyond when compared to placebo (9.3 vs. 6.6 months); hazard ratio 0.65 (P < 0.001) and led to its approval in China. Methods: This is an ongoing Ph 1/1b open-label, dose escalation/expansion study conducted in the US. Here we present the preliminary safety and antitumor efficacy data from pts with refractory mCRC in Cohort (Coh) B (progressed on all standard therapies including TAS-102 [TAS] and/or regorafenib [R]) and in Coh C (did not receive TAS or R). Results: As of data cutoff on 27 July 2021, 81 mCRC pts had been treated (41 in Coh B and 40 in Coh C); median age of 57 years (range: 34─77), Caucasian (81.5%), female (44.4%), and ECOG PS 1 (59.3%). In Coh B, the median number of prior therapies was 5 (range: 3-9), 8 pts (19.5%) received R, 19 (46.3%) received TAS and 14 (34.1%) received both R and TAS. In Coh C, the median number of prior therapies was 4 (range: 1-10). Five pts remain on treatment; reasons for treatment discontinuation included: 56 pts (69.1%) due to progressive disease or death, 8 pts (9.9%) due to adverse events (AE), and 12 pts (14.8%) due to withdrawal of consent or physician decision. The median duration of F treatment was 4.4 months (range: 0.7– 20.0) in Coh B and 3.7 months (range: 0.02-14.3) in Coh C. The most frequently reported AEs of any grade in Coh B were fatigue (53.7%), proteinuria (51.2%), and hypertension (HTN; 48.8%). In Coh C the most frequently reported AEs of any grade were HTN (75.0%), proteinuria (40.0%), and myalgia (32.5%). Hand-foot syndrome (HFS) was reported in 29.3% of Coh B pts and 22.5% of Coh C pts. The disease control rate [DCR] was 68.3% in Coh B (1 partial response [PR] and 27 stable disease [SD]) and 59.5% for the 37 patients with at least one post-baseline tumor assessment in Coh C (2 PRs and 20 SDs). Conclusions: F is generally well-tolerated in heavily-pretreated pts with refractory mCRC. Evidence of antitumor activity was observed in cohorts B and C. The multi-cohort dose expansion is ongoing. F is being further investigated in refractory mCRC in a global Ph 3 study (NCT04322539). Clinical trial information: NCT03251378.

Bortezomib treatment causes remission in a Ph+ALL patient and reveals FoxO as a theranostic marker

BCR-ABL is a key mediator in the pathogenesis of all cases of chronic myelogenous leukemia (CML) and a subset of precursor B-acute lymphoblastic leukemia (Ph+ALL). Previous animal and cell-based studies have shown that the expression of members of the Forkhead family of tumor suppressors, including FoxO3, is suppressed in BCR-ABL-expressing cells. Furthermore, it has been reported that the proteasomal degradation pathway plays an important role in suppression of FoxO expression in BCR-ABL-transformed cells. In this study, a patient diagnosed with Ph+ALL and refractory to standard therapies was treated with a proteasome inhibitor (bortezomib)-based chemotherapy regimen. This treatment resulted in complete hematologic, cytogenetic and molecular remission with excellent performance status for > 4 years since her initial diagnosis. FoxO3 was not detectable within the blasts of this patient at diagnosis and was 'rescued' following treatment with bortezomib therapy, leading to her recovery. As a next step, in the attempt to propose FoXO3 as a therapeutic target and a theranostic marker, we further validated FoxO3 expression in human bone marrow biopsy samples. Human core biopsy samples of Ph+ALL and Ph-negative-negative ALL, along with uninvolved controls, revealed that FoxO3 down-regulation was specific to Ph+ALL. This study provides support that FoxO3 is a good biomarker for BCR-ABL-mediated leukemogenesis. Additionally, proteasomal inhibition by bortezomib may be a promising therapeutic option in Philadelphia-positive ALL, where FoxO3 is downregulated.

Proteasome inhibition causes regression of leukemia and abrogates BCR-ABL-induced evasion of apoptosis in part through regulation of forkhead tumor suppressors

BCR-ABL plays an essential role in the pathogenesis of chronic myeloid leukemia (CML) and some cases of acute lymphocytic leukemia (ALL). Although ABL kinase inhibitors have shown great promise in the treatment of CML, the persistence of residual disease and the occurrence of resistance have prompted investigations into the molecular effectors of BCR-ABL. Here, we show that BCR-ABL stimulates the proteasome-dependent degradation of members of the forkhead family of tumor suppressors in vitro, in an in vivo animal model, and in samples from patients with BCR-ABL-positive CML or ALL. As several downstream mediators of BCR-ABL are regulated by the proteasome degradation pathway, we also show that inhibition of this pathway, using bortezomib, causes regression of CML-like disease. Bortezomib treatment led to inhibition of BCR-ABL-induced suppression of FoxO proteins and their proapoptotic targets, tumor necrosis factor-related apoptosis-inducing ligand and BIM, thereby providing novel insights into the molecular effects of proteasome inhibitor therapy. We additionally show sensitivity of imatinib-resistant BCR-ABL T315I cells to bortezomib. Our data delineate the involvement of FoxO proteins in BCR-ABL-induced evasion of apoptosis and provide evidence that bortezomib is a candidate therapeutic in the treatment of BCR-ABL-induced leukemia.