Phase IB study of gene-mediated cytotoxic immunotherapy adjuvant to up-front surgery and intensive timing radiation for malignant glioma

Abstract

Purpose: Despite aggressive therapies, median survival for malignant gliomas is less than 15 months. Patients with unmethylated O(6)-methylguanine-DNA methyltransferase (MGMT) fare worse, presumably because of temozolomide resistance. AdV-tk, an adenoviral vector containing the herpes simplex virus thymidine kinase gene, plus prodrug synergizes with surgery and chemoradiotherapy, kills tumor cells, has not shown MGMT dependency, and elicits an antitumor vaccine effect.

Patients and methods: Patients with newly diagnosed malignant glioma received AdV-tk at 3 × 10(10), 1 × 10(11), or 3 × 10(11) vector particles (vp) via tumor bed injection at time of surgery followed by 14 days of valacyclovir. Radiation was initiated within 9 days after AdV-tk injection to overlap with AdV-tk activity. Temozolomide was administered after completing valacyclovir treatment.

Results: Accrual began December 2005 and was completed in 13 months. Thirteen patients were enrolled and 12 completed therapy, three at dose levels 1 and 2 and six at dose level 3. There were no dose-limiting or significant added toxicities. One patient withdrew before completing prodrug because of an unrelated surgical complication. Survival at 2 years was 33% and at 3 years was 25%. Patient-reported quality of life assessed with the Functional Assessment of Cancer Therapy-Brain (FACT-Br) was stable or improved after treatment. A significant CD3(+) T-cell infiltrate was found in four of four tumors analyzed after treatment. Three patients with MGMT unmethylated glioblastoma multiforme survived 6.5, 8.7, and 46.4 months.

Conclusion: AdV-tk plus valacyclovir can be safely delivered with surgery and accelerated radiation in newly diagnosed malignant gliomas. Temozolomide did not prevent immune responses. Although not powered for efficacy, the survival and MGMT independence trends are encouraging. A phase II trial is ongoing.

Conflict of interest statement

Authors' disclosures of potential conflicts of interest and author contributions are found at the end of this article.

Figures

Fig 1.

Study design. An adenoviral vector containing the herpes simplex virus thymidine kinase gene (AdVtk) was injected at the time of surgery in a total volume of 1 mL divided into 10 injection sites in residual tumor in the surgical wall. Valacyclovir was administered at 2 gm three times per day for 14 days starting on days 1 to 3. Radiation was started 4 to 9 days after AdVtk injection to overlap with AdVtk activity and valacyclovir administration. Temozolomide was administered after completing valacyclovir. Differences in the study design compared with other recent studies with adenoviral delivery of herpes simplex virus thymidine kinase to newly diagnosed malignant gliomas include vector delivery: 1 mL in 10 sites versus 10 mL in 30 to 70 injection sites; prodrug: oral valacyclovir versus intravenous ganciclovir over 1 hour twice per day; radiation timing: accelerated radiation targeting within 7 days after surgery versus radiation delayed to 3 to 6 weeks after surgery. Differences highlighted in the figure as follows: (*) vector delivery; (†) prodrug; (‡) radiation timing.

Fig 2.

Kaplan-Meier analysis of overall survival and progression-free survival. The top two curves include all evaluable patients at dose levels 1, 2, and 3, and the bottom two curves include the 10 patients with glioblastoma multiforme.

Fig 3.

Slow resolution of magnetic resonance imaging enhancement; magnetic resonance imaging of patient 1B3 at dose level 1. Before surgery and injection (panel A) imaging shows a glioblastoma multiforme in the left temporal lobe. Postoperative images (panel B) reveal a total resection. Residual ring enhancement is apparent 4 weeks after completion of radiation (panel C), which gradually resolved over the next 6 months. Decreased enhancement 4 months after radiation completion is shown in panel D. Adjuvant temozolomide was stopped after four cycles because of noncompliance. However, the patient did not develop progression until 27 months and survived for 46 months.

Fig 4.

Histologic analysis of re-resected tumors. Re-resection of glioblastoma multiforme at 30 weeks in patient 1B4 with demonstration of intratumoral lymphocytic infiltrate (A) via staining with hematoxylin and eosin, which was found to be CD3+ T cells by immunohistochemistry. (B) Anti-CD3 antibody. Re-resection of glioblastoma multiforme at 36 weeks in patient 2B2 with demonstration of macrophage (C) and cell (D) infiltration. (C) Anti-CD68 antibody. (D) Anti-CD3 antibody. Anti-CD20 staining for B cells was negative (not shown). Arrows point to positive cells.

Fig A1.

Patient-reported outcomes from the Functional Assessment of Cancer Therapy-Brain (FACT-Br) questionnaire before and after treatment. Colored bars show average and black vertical bars show standard deviation for each subscore and the total score for each time period. n, number of patients evaluated in each time period. AC, Additional Concerns section (brain subscale); GE, General Emotional Well-Being; GF, General Functional Well-Being; GP, General Physical Well-Being; GS, General Social/Family Well-Being.