AV-GBM-1 Cancer Vaccine Improves PFS in Newly Diagnosed Glioblastoma

Robert O. Dillman, MD

The personalized cancer vaccine AV-GBM-1, developed by AIVITA Biomedical Inc., significantly improved progression-free survival (PFS) over standard of care (SOC) in patients with newly diagnosed glioblastoma, according to data from a phase 2 trial (NCT03400917).¹

Among 57 patients who had received 8 doses of the vaccine over about 6 months, the median PFS was 10.4 months (95% CI, 8.6-11.7) with AV-GBM-1 vs the 6.9 months (95% CI, 5.8-8.2) that had been observed with radiotherapy plus temozolomide in the landmark STUPP study;² this translated to about a 50% improvement over the established SOC for this population.

At the time of the analysis, patients had completed therapy and had been followed between 10.1 months and 27.6 months from enrollment. The median overall survival (OS) had not yet been reached and will be evaluated after the last patient has had a minimum follow-up of 15 months.

Moreover, AV-GBM-1 was found to be well tolerated, overall, with 54 serious adverse effects reported in 28 patients; however, none of these toxicities were determined to be associated with the vaccine.

“The potential for AV-GBM-1 to significantly improve PFS in [patients with] newly diagnosed glioblastoma over and above current SOC is very encouraging,” Robert O. Dillman, MD, chief medical officer of AIVITA, stated in a press release. “We look forward to confirming this benefit in a randomized phase 3 multicenter trial.”

Standard treatment strategies for patients with primary glioblastoma have been associated with poor survival outcomes. Investigators hypothesized that the use of adjunctive therapy with individualized vaccines could potentially enhance immune response which could improve outcomes.

AV-GBM-1 is an immunotherapy that is comprised of autologous dendritic cells that are full of autologous tumor neoantigens that are derived from self-renewing tumor-initiating cells that are taken from tumors following routine surgical debulking. Patients receive the vaccine via subcutaneous injection. Notably, the approach is pan-antigenic, targeting several antigens from autologous tumor-initiating cells that play a role in tumor growth.

Previously, data with the AV-GBM-1 vaccine were presented during the 2020 SITC Annual Meetingand demonstrated that the vaccine induced a PFS rate of 69% at 7 months, which compared favorably with the historical rate of 50% at this time point.³

Specifically, the median PFS was 10.0 months (95% CI, 8.5-11.5) with the vaccine compared with 6.9 months (95% CI, 5.8-8.2) in the landmark study, which had translated to a 38% reduction in the risk of progression or death at 6.9 months of treatment. Moreover, the 12-month OS rate was 72% with the vaccine vs 61% with the historical control.

For the phase 2 trial, patients were enrolled after they recovered from surgery and before they initiated concurrent treatment with temozolomide and radiation. Patients needed to have a diagnosis of primary glioblastoma, be aged 70 years or younger at the time of resection, have successful cell culture of cancer cells in serum-free media, have acceptable monocyte collection via leukapheresis, and a Karnofsky performance score (KPS) of 70 or greater after surgical recovery.

Interleukin-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were used to produce dendritic cells from peripheral blood monocytes. These cells were created with autologous tumor antigens from the lysate of the cancer cells to create every vaccine that is individualized to the patient. Participants started treatment following recovery of concurrent chemotherapy/radiation, and with each vaccine dose, they were given GM-CSF at 500 mcg at the time of injection (on weeks 1, 2, 3, 8, 12, 16, 20, and 24).

Between August 18, 2018, and January 15, 2020, tumors were collected. Patients were enrolled for treatment between October 3, 2018, and February 27, 2020. Eighty tumors were received; 71 of 73 were found to have successful cell lines. A total of 7 patients withdrew while the cell line was in progress. Sixty-five leukapheresis procedures were done, but 6 patients withdrew before this. A total of 60 patients were enrolled to the intent-to-treat population but 3 withdrew prior to treatment initiation.

The median age of these patients was 59 years and 70% of patients were male. Moreover, 72% were White, 17% were Hispanic, 3% were Black, and 2% were Asian. Fifty-two percent of patients did not have MGMT methylation and 12% had IDH-mutated disease. Additionally, 42% of patients had a KPS of 90, while 28% had a score of 80, 23% had a score of 70, and 7% had a score of 100.

At this time point, the vaccine was also found to have good tolerability, with the most frequently reported effect being local injection site reactions. No patients had discontinued treatment due to toxicities.

“This milestone is an encouraging first step in the fight against glioblastoma, a disease that has devastating impact on patients and their families,” Daniela Bota, MD, PhD, director at the University of California, Irvine (UCI) Alpha Stem Cell Clinical and medical director of UCI Health Comprehensive Brain Tumor Program, added in the press release.

Two ongoing clinical trials are evaluating the vaccine in patients with glioblastoma and melanoma in the United States.

References

1. AIVITA Biomedical’s phase 2 glioblastoma trial shows improved progression free survival. News release. AIVITA Biomedical, Inc. June 8, 2021. Accessed June 8, 2021. https://prn.to/3fZDrd8
2. Stupp R, Mason WP, van den Bent MJ, et al. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med. 2005;352(10):987-996. doi:10.1056/NEJMoa043330
3. Bota DA, Piccioni DE, Duma CM, et al. Phase II trial of active specific immunotherapy in primary glioblastoma: antigens from self-renewing autologous tumor cells presented by autologous dendritic cells. Presented at: 2020 SITC Annual Meeting; November 9-14, 2020; Virtual. Abstract 745.