Glioblastoma vaccine yields promising interim survival results in Phase III trial

Interim blinded survival data has been released from the Phase III clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma patients; early findings from the 11-year study involving more than 300 individuals worldwide demonstrates promising survival results.

In this study, patients were randomized to receive temozolomide plus DCVax®-L (an autologous tumor lysate-pulsed dendritic cell vaccine) or temozolomide and placebo. The data that has been recently published in the Journal of Translational Medicine is blinded aggregate data, which includes patients from both arms of the trial combined.

The trial is ongoing while the data continues to mature, and the company, the investigators and patients all remain blinded.

Once the patients experienced tumor recurrence, all patients from both arms were allowed to cross over and start receiving DCVax-L, but without being unblinded as to what they had received before tumor recurrence.  This resulted in approximately 90%, of the total 331 patients, in the trial receiving DCVax-L treatment.

The median survival, for all 331 patients (both arms of the trial combined), was 23.1 months from surgery. In comparison, median survival for newly diagnosed glioblastoma patients with the standard of care (surgery, radiation and chemotherapy) is 15–17 months.

Meanwhile for patients with a methylated MGMT gene status median survival was 34.7 months from surgery; with standard of care median survival for this cohort of patients reported to be 21.7 months. Patients with an unmethlyated MGMT status also experienced survival benefit of 19.8 months in comparison to 12.7 months with standard of care.

“These are just interim data, and the data may get either better or worse as they continue to mature,” commented Linda Powers from Northwest Biotherapeutics (MD, USA). “However, the survival times we are seeing are encouraging, especially in light of how little progress has been made in decades in treatments for glioblastoma.”

Of particular importance, the “long tail” of the survival curve for patients in this DCVax-L trial was promising; patients who survived past certain time points have continued onwards to substantially extended survival. For example, 223 patients were ≥30 months past their surgery date as of this analysis; 30% of these patients have lived ≥30 months and these patients have Kaplan-Meier -derived median survival estimate of 46.5 months.

Furthermore, as of this analysis, 182 patients were ≥36 months past their surgery date; 24.2% have lived ≥36 months and these patients have Kaplan-Meier -derived median survival estimate of 88.2 months.

In addition, DCVax-L has demonstrated an excellent safety profile in the trial; it has been administered over 2000 times, and only 7 of the 331 patients (2.1%) have experienced a serious adverse event that was deemed at least possibly related to the treatment. The rate of total adverse events (including non-serious events) was comparable to the rate of adverse events with standard of care alone.

Sources: Liau LM, Ashkan K, Tran DD et al. First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma J. Transl. Med. doi:10.1186/s12967-018-1507-6 (2018) (Epub ahead of print); www.nwbio.com/nwbio-announces-scientific-publication-interim-survival-data-phase-3-trial-dcvax-l-glioblastoma-brain-cancer/