On November 16, 2018 Agios Pharmaceuticals, Inc. (NASDAQ:AGIO), a leader in the field of cellular metabolism to treat cancer and rare genetic diseases, reported its updated data from the ongoing Phase 1 study evaluating single agent AG-881 in advanced glioma (Press release, Agios Pharmaceuticals, NOV 16, 2018, View Source [SID1234531460]). The data were featured in an oral presentation at the Society for Neuro-Oncology (SNO) Annual Meeting in New Orleans. AG-881 is an investigational, oral, selective, potent inhibitor of the mutant isocitrate dehydrogenase-1 (IDH1) and IDH2 enzymes and was designed for enhanced brain penetrance for development in IDH-mutant glioma.

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"With additional follow-up, the AG-881 Phase 1 dose-escalation data continue to show a favorable safety profile at the doses selected for the perioperative study. Longer treatment duration and a reduction in tumor growth rates are encouraging signs of clinical activity in low-grade glioma," said Ingo Mellinghoff, M.D., Memorial Sloan Kettering Cancer Center, an investigator for the study. "Ultimately, use of an IDH inhibitor in this difficult-to-treat disease has the potential to improve the current treatment paradigm by delaying the multiple rounds of surgery, radiation and chemotherapy that many patients endure."

"With no curative or approved targeted therapies and a high frequency of IDH1 mutations in low-grade glioma, we are committed to advancing one of our IDH inhibitors to a registrational study in this disease," said Chris Bowden, M.D., chief medical officer at Agios. "We are continuing to collect clinical data for both ivosidenib and AG-881, along with feedback from regulators and the neuro-oncology community, to make an internal decision on our glioma pivotal strategy by the end of this year."

Study Status

AG-881 is being evaluated as a single agent in an ongoing Phase 1 dose-escalation trial in IDH1/2 mutant advanced solid tumors, including glioma. Enrollment was completed in June 2017. Dose escalation data as of March 29, 2018 were presented at the 2018 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting. As of the updated July 20, 2018 data cut-off, study design, enrollment and baseline characteristics of the 52 glioma patients remain unchanged, as reported below.

Forty-eight percent of patients (n=25) had World Health Organization (WHO) classified Grade 2 tumors, 42% (n=22) had Grade 3 tumors, 8% (n=4) had Grade 4 tumors and 2% (n=1) was unknown.
The median age of these patients is 42.5 years (ranging from 16-73 years).
Patients received a median of two prior systemic therapies (ranging from one to six).
Seventy-three percent of patients (n=38) had previously received temozolomide and 58% percent (n=30) had previously received radiotherapy.
Patients received daily doses of AG-881 ranging from 10 mg to 300 mg.
Updated safety and efficacy data on the 52 patients with enhancing and non-enhancing glioma, including an exploratory tumor volume growth rate analysis, are reported below.

Fourteen patients remain on treatment, including 13 patients with non-enhancing disease.
Of the 38 patients who discontinued treatment, 76.3% (n=29) discontinued for disease progression and 5.2% (n=2) discontinued due to an AE.
The median treatment duration was 6.3 months (ranging from 0.2-32 months) for all glioma patients, 15 months (ranging from 1-32 months) for non-enhancing glioma and 3.25 months (ranging from 0.2- 32 months) for patients with enhancing disease.
Thirty-seven percent of patients (n=19, including 15 patients with non-enhancing disease) remained on treatment for ≥1 year.
Safety Data

The safety analysis conducted for all 52 glioma patients as of the data cut-off demonstrated that AG-881 continues to have a favorable safety profile at dose levels below 100 mg.

The majority of adverse events (AEs) reported by investigators were mild to moderate, with the most common (>30%) being increases in alanine aminotransferase (ALT) (n=23), increases in aspartate aminotransferase (AST) (n=21), headache (n=19) and fatigue (n=17).
Grade 3 or higher AEs were observed in 19% of all patients (n=10). AEs occurring in more than one patient included seizure (n=4), ALT increases (n=3) and AST increases (n=2).
As reported in June, dose limiting toxicities (DLTs) of Grade 2 or higher elevated transaminases occurred in five glioma patients at the higher dose levels (≥100 mg) and resolved to Grade ≤1 with dose modification or discontinuation. There were no new DLTs reported as of the new data cut-off or any treatment-related on-treatment deaths.
Doses of 10 mg and 50 mg are under evaluation in an ongoing perioperative study in non-enhancing glioma.
Efficacy Data

Efficacy data from the 52 glioma patients (22 with non-enhancing and 30 with enhancing disease) as of the data cut-off showed:

One patient with non-enhancing disease and a 1p19q co-deletion had a confirmed / sustained partial response according to the investigator by Response Assessment in Neuro-Oncology for low grade glioma (RANO-LGG) and remains on treatment.
One patient with non-enhancing disease and a 1p19q co-deletion had a confirmed / sustained minor response according to the investigator by RANO-LGG and remains on treatment.
Sixty-nine percent of patients (n=36) had a best response of stable disease, including 82% (n=18) patients with non-enhancing disease.
For non-enhancing patients with available data (n=18), the average volumetric six-month tumor growth was 6.8% following treatment with AG-881; pre-treatment volumetric growth rates were not available for these patients. For a similar population of IDHm low-grade glioma patients in the ongoing Natural History study, the average six-month volumetric growth prior to treatment was 24.5%.
Ongoing Glioma Perioperative Study Presented in Trials in Progress Poster
A perioperative ‘window’ trial with ivosidenib and AG-881 (10 mg and 50 mg) in up to 45 IDH1m non-enhancing low-grade glioma patients is ongoing and being presented today as part of a trials in progress poster. The goal of the trial is to confirm CNS penetrance and tumor 2-HG suppression of ivosidenib and AG-881 as part of the strategy to finalize internal pivotal development plans by year-end 2018.

About Glioma
Glioma presents in varying degrees of tumor aggressiveness, ranging from slower growing (low-grade glioma) to rapidly progressing (high-grade glioma-Glioblastoma Multiforme). Common symptoms include seizures, memory disturbance, sensory impairment and neurologic deficits. The long-term prognosis is poor with a five-year survival rate of 33 percent. Approximately 11,000 low-grade glioma patients are diagnosed annually in the U.S. and EU and approximately 80 percent have an IDH1 mutation.