Approaches Based on Immunotherapy to Fight Glioblastoma Multiforme (Part Two)

Here we are at the twelfth episode of Ben Williams’ guide translation project on treatment options for Glioblastoma Multiforme. This is the second and final part of chapter 8 of the guide. In this episode we talk about immunotherapy and in particular about anti-EGFRvIII vaccine, WT1 peptide vaccine, Poly-ICLC, PD-1 and PD-L1 immune check point inhibitors and therapies with CAR T cells targeted at EGFRvIII and IL13Rα2. The advice is yet to use this information to discuss it with the medical team that is taking care of you. You can point them to the references to supporting scientific works.
I ask you once again if it is possible to help the fundraising campaign Glioblastoma.it for CUSP-ND for Emanuele at least by sharing the link in order to spread the word and raise awareness as many people as possible. Enjoy the reading!

Rindopepimut: anti-EGFR variant III vaccine (EGFRvIII)

A very different approach to the development of a therapeutic vaccine, which has the advantage of being usable “off-the-shelf”, without modification for individual patients, aims at a mutation of the epidermal growth factor receptor, known as variant III, occurring in 25-40% of GBMs. One reason EGFR inhibitors like Iressa have not been more effective is that they target the normal EGFR receptor, not this mutated receptor. Variant III of EGFR is also rarely seen in anything other than GBM tumors. To participate in the trial, patients first need to know if they have the mutation.
Disappointing news was provided by Celldex in a press release dated March 7, 2016, when the company announced that the Phase III ACT IV clinical trial using rindopepimut for newly diagnosed glioblastoma patients would be discontinued after a committee independent review found that the study was unlikely to meet its primary endpoint (overall survival improvement). Although survival results were consistent with previous phase II studies, the control arm in this study had better than expected survival outcomes (median overall survival was 20.4 months in the rindopepimut arm and 21.1 months in the control arm, hazard ratio = 0.99).
Rindopepimut was also tested in a randomized phase II trial for recurrent glioblastoma called ReACT, in combination with Avastin. The data presented at the 2015 ASCO meeting showed that the primary objective of the study (progression-free survival of six months) was achieved. PFS-6 was 30% in the rindopepimut + Avastin arm, compared with 12% in the control arm. Additional data (340, IMCT-08 abstract) presented at the same SNO meeting, demonstrated that overall survival was also significantly improved and the 2-year survival was 25% for the rindopepimut arm versus 0% in the control arm. Patients who received rindopepimut also achieved reduced dependence on steroids, as 33% of patients were able to stop steroid treatment for six months or more, compared with no patients in the control group.
Although development of Rintega (rindopepimut) is unlikely to become a first-line treatment for GBM based on these findings, therapy is still promising when combined with Avastin in the recurrent setting, according to the results of the ReACT study.

Wilms Tumor 1 (WT1) peptide vaccine

In March 2015, a Japanese group published the results of a study that tested a peptide vaccine used against Wilms tumor 1 (WT1) in combination with radiation and chemotherapy for newly diagnosed glioblastoma (341). Wilms Tumor 1 (WT1) is an overexpressed protein in various types of solid and liquid tumors, not to be confused with the pediatric cancer from which it takes its name (Wilms’ Tumor). Seven patients were included in the analysis, with four undergoing total tumor resection, two with partial resection and one with only biopsy. None of the tumors were positive for the IDH1 mutation. Patients received up to 24 monthly courses of temozolomide, the standard of care. Surprisingly, five of these seven patients (71%) were still disease free at three years or more. Only one patient had experienced disease progression at the time of the analysis and all were still alive. Median progression-free and overall survival was at least 43.5 months (approximately 3.5 years), which was the median follow-up time at the time of analysis. These impressive results were probably not simply due to the prolonged courses of temozolomide: in the same institution, the median PFS and OS with up to 24 courses of TMZ (thus without the vaccine) is 10.7 and 21 months, respectively.
An abstract (342, IMCT-09 abstract) presented at the 2015 SNO meeting informs that the median progression-free survival for the seven patients is now greater than 48 months (4 years) as five of the seven patients were still progression-free at the time of publication.

Vaccine adjuvants: Poly-ICLC

A generalized immunostimulant with minimal toxicity is Poly-ICLC, a double-stranded RNA, which was initially developed to induce the body to produce its own interferon, but is now believed to have a variety of immune-enhancing effects. including the deactivation of an as yet unknown tumor suppressor mechanism of the immune system. These latter effects apparently occur only at low doses and are suppressed by high doses of Poly-ICLC. Initial results for AA-III tumors were outstanding: the initial clinical trial with Poly-ICLC (in combination with CCNU for approximately 1/2 of the patients) reported that all but one of the AA-III tumor patients were alive to a median follow-up time of 54 months (145). Poly-ICLC was less effective on glioblastomas, with a median survival time of 19 months (which however is longer than standard treatment). There were minimal side effects with the exception of a mild fever at the start of treatment (145). However, a more recent multicenter clinical trial with recurrent AA-III tumors yielded less impressive results (146), as the group of treated patients had a PFS-6 value of only 23%. Note, however, that the latter study involved patients with recurrent tumors while the previous study involved patients after the initial diagnosis.
Two studies have recently been reported using Poly-ICLC on patients with newly diagnosed glioblastoma. In the first, Poly-ICLC was administered in combination with standard radiation, followed by its use as a single agent (147). No chemotherapy was given. One-year survival was 69% and median survival was 65 weeks (approximately 15 months). Both values ​​are superior to historical studies that used only radiation without chemotherapy. In the second study with 83 patients with newly diagnosed glioblastoma (148), Poly-ICLC was combined with the standard temozolomide and radiation protocol. For 97 patients, the median survival was 18.3 months with a 2-year survival rate of 32%. Therefore, the addition of Poly-ICLC increases survival by several months, compared to the standard protocol, with minimal additional toxicity.
The fact that immunological treatments have produced at least some degree of success is encouraging and underlines the need to strengthen the patient’s immune function as much as possible. The effects of melatonin and mushroom extracts such as PSK presumably contribute at least in part to that strengthening, and therefore should generally be beneficial.

Immune checkpoint inhibitors (drugs targeting CTLA-4, PD-1, PD-L1 etc.)

Another immunotherapy approach involves the combination of two new immunological agents, ipilimubab (Yervoy) and nivolumab (Opdivo), which have produced unprecedented clinical efficacy in the treatment of metastatic melanoma, one of the most intractable of malignant tumors. For patients who used the combination at the highest dose, 53% had tumor regression, all with a reduction of 80% or more (176). This treatment protocol is now being tested with multiple different forms of cancer, including glioblastoma.
At the 2015 ASCO Annual Meeting, the results of 20 recurrent GBM patients treated with nivolumab (3 mg / kg) or nivolumab (1 mg / kg) plus ipilimumab (3 mg / kg) were reported. In the nivolumab arm, no patients discontinued due to toxicity, while in the combined arm, 3 out of 10 patients discontinued due to drug toxicity.
Further information on this research was produced concurrently with the 2016 ASCO Annual Meeting. These are the characteristics of the three groups: the first received nivolumab only (n = 10), the second nivolumab 1 mg / kg plus ipilimumab 3 mg / kg ( n = 10) and a third previously unreported group who received nivolumab 3 mg / kg plus ipilimumab 1 mg / kg (n = 20). Stable disease or positive response was achieved in 6/10 (60%) of patients in the nivolumab-only group, in 4/10 (40%) of patients who received nivolumab plus ipilimumab (1 and 3 mg / kg) and in 9/20 (45%) of patients who received nivolumab plus ipilimumab (3 and 1 mg / kg). The 12-month overall survival rate for these same 3 groups was 40%, 30%, and 25%. According to the press release, the median survival for the three groups was 10.5, 9.3, and 7.3 months. Based on these results, it can be inferred that adding ipilimumab to nivolumab therapy does not improve response and increases patient toxicity.
In early April 2017 Bristol-Myers Squibb, the manufacturer of nivolumab, announced that their Phase 3 Checkmate-143 study failed to meet its primary endpoint, which was improvement in overall survival with nivolumab. compared to bevacizumab monotherapy (Avastin). A research summary published for the May 2017 World Meeting of Neuro-Oncology Societies provided further details. In this trial, 182 patients with recurrent glioblastoma received nivolumab treatment and 165 received Avastin. Median overall survival from study entry was 9.8 months with nivolumab compared to 10 months with Avastin and the 12-month survival rate was 42% in both arms. Median progression-free survival was 1.5 months with nivolumab compared with 3.5 months with Avastin. The response rate was 8% for nivolumab compared to 23% for Avastin. However, for responding patients, responses were more durable with nivolumab – a median of 11.1 months compared with 5.3 months for Avastin. While disappointing, these findings are perhaps not surprising given previous reports of low response rates (1 in 10 patients responded to nivoluamb alone at an earlier stage of the same NCT02658279 study) and suggest that these therapies need to be administered in conjunction with other agents, rather than as monotherapy.

Hyperprogression following anti PD-1 / PD-L1 therapy

At the end of 2016, a somewhat disturbing study appeared (358) showing that in a minority of patients treated with antibodies directed against PD-1 or PD-L1 immune checkpoints, treatments can lead to accelerated disease progression, defined such as an increase in tumor growth at a rate of at least 2 times that of the pretreatment period. This study included all patients treated at the Gustave Roussy Institute in the phase 1 studies that tested monotherapy with antibodies to PD-1 or PD-L1, between December 2011 and January 2014. Of the 131 patients evaluated, 12 (9% ) have had hyperprogressive disease following therapy. For the twelve patients who responded to PD-1 or PD-LI antibodies with hyperprogressive disease, the tumor growth rate increased by a median of 20.7-fold.
Several months after the publication of the Gustave Roussy Institute, another group published a report attempting to identify genomic alterations associated with the hyperprogression response to immune checkpoint inhibitors (antibodies to CTLA-4, PD-1 or PD-L1). This study included 155 patients with stage IV cancers treated with checkpoint inhibitors. It is significant that four out of five patients (80%) with MDM2-amplified tumors exhibited hyperprogression after anti-PD-1 or PD-L1 monotherapy. Two out of ten patients (20%) with EGFR alterations (presumably amplification or mutation) had hyperprogression and the EGFR alterations were independently associated with early treatment failure on checkpoint inhibitors. Eight out of 10 patients with EGFR alterations decreed treatment failure (TTF) in less than 2 months.
The authors concluded with the observation that patients for whom anti-PD1 / PDL1 monotherapy is planned must carry out genomic tests to determine if their tumors harbor specific alterations associated with hyperprogression. In particular, those who find themselves having MDM2 amplification in their tumors must avoid these therapies.

T cell therapies

Therapy of chimeric antigen receptor T cells

Chimeric antigen receptor (CAR) T cells are T cells that have been genetically engineered, commonly through the use of a retroviral vector, to express artificial receptors specifically targeted to a tumor-specific or tumor-associated antigen. CD19-directed CAR T cells have been used with impressive success for B-cell acute lymphoblastic leukemia (ALL) and tisagenlecleucel, an anti-CD19 CAR T cell therapy was approved for this indication on August 30, 2017. glioblastoma, CAR T cell phase 1 studies are currently active, with preliminary results now published for two of these studies, as discussed below.

CAR T cells directed by EGFRvIII

In 2014, a phase 1 safety and feasibility study began recruiting at the University of Pennsylvania to test treatment with autologous CAR T cells redirected to the EGFRvIII mutant protein for patients with EGFRvIII-positive recurrent glioblastoma. Of the 369 patients with glioblastoma, 21% tested positive for the EGFRvIII mutation. Fourteen patients underwent leukapheresis to obtain T cells and 10 were eventually infused with EGFRvIII CAR T cells. The findings and observations based on these 10 cases are described in a July 2017 publication (359).
Due to the uncertainty of the interpretation of MRI images in the context of immunotherapy, the study focused on the trafficking of CAR T cells in tumors and their effects, rather than on response rates based on MRI imaging. Without the ability to directly visualize CAR T cells in the brain, the study was based on examining the resected tumor tissue of seven of the ten patients. Four of these patients had early progression before T-cell infusion and underwent surgical resection of the tumor within 14 days of T-cell infusion. Three more patients underwent ‘late’ surgery from 34 to 104 days after T cell infusion, due to suspected relapses based on MRI imaging. Therefore, early and late time points were available for the analysis of CAR T cell trafficking in the tumor.
The study met the primary endpoint of safety and feasibility, as successful production of the target CAR T cell dose and successful engraftment in peripheral blood was achieved for all patients, despite having been heavily pretreated with prior chemotherapy. . No dose-limiting toxicities were observed, although two patients were treated with the anti-IL-6 antibody siltuximab due to suspected release of intracranial cytokines.
In the four patients who underwent early resection within two weeks of CAR T cell infusion, CAR T cells were detected in tumor tissue, with a significantly increased prevalence in tumor compared to blood in two of the patients (concentrations 3 and 100 times higher). elevated in the brain compared to peripheral blood). In the three patients with late resections (from one to three months) after infusion of T cells, CAR T cells were detected only in one case, at lower levels than in the blood. Five of the seven post-infusion resected tumor samples showed a mean decrease in EGFRvIII expression compared to paired pre-infusion samples.
Some tumor samples showed robust infiltration of T and CAR T cells after infusion, with multiple activated CD8 cytotoxic T cells, although in all tumors with detectable CAR T cells, the infiltration was irregular and inconsistent.
Unsurprisingly, the tumors have adapted to CAR T cell therapy causing the upregulation of immunosuppressive mechanisms and proteins such as IDO1, PD-L1 and the infiltration of immunosuppressive regulatory T cells.
In terms of clinical results, three of the ten patients were still alive about 100 days, 200 days and 18 months after the infusion. The latter patient was still progression-free for the entire duration of the study. According to the Kaplan-Meier estimate, the median survival of the 10 patients from infusion was 251 days (just over 8 months), which is perhaps better than expected considering that eight of the 10 patients were on the third or fourth line of treatment. (at second or third relapse), and nine of the 10 patients had multifocal disease, with the remaining patient having deep midbrain / thalamic tumor. This cohort was therefore composed of patients with a rather poor prognosis at the base. Particularly impressive is the only case with progression-free survival of more than 18 months.
The authors rightly concluded that due to the heterogeneous expression of EGFRvIII by tumors and the increasingly immunosuppressive microenvironment created by tumors after CAR T infusion, future therapies and trials will require targeting more antigens to prevent escape. antigen and combined therapies to counteract the increased expression of immunosuppressive molecules. Combined therapies could include the use of drugs targeting IDO1 and / or PD-1 / PD-L1 antibodies.

T cells of the chimeric antigen receptor targeted at IL13Rα2 (CAR T cells)

A remarkable case study of a 50-year-old patient with recurrent glioblastoma treated with chimeric antigen receptor (CAR) T cells targeting interleukin 13 alpha 2 (IL13Rα2) was published in late 2016 by researchers from City of Hope (360). This patient suffered from aggressively recurrent GBM, with multifocal leptomeningeal metastases, thus with a markedly poor prognosis. The patient was enrolled in the CAR IL13Rα2 T cell study and received 6 infusions of T cells into the resection cavity after resection of three of the five intracranial tumors. With these weekly intracavitary infusions, the primary tumor site remained stable, while several new tumors appeared, including two in the spine, and the unresected tumors continued to progress. At this point the patient was enrolled in a compassionate use protocol to receive intraventricular infusions of CAR-T lymphocytes, on the grounds that such infusions would reduce the traffic of T cells to distant sites of multifocal disease. After treatment with five intraventricular infusions, all tumors had decreased from 77% to 100%, and after 10 infusions no tumors were detectable by MRI or PET scan, including metastatic spinal tumors.

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(145) Salazar, A. M., et al. Long-term treatment of malignant gliomas with intramuscularly administered polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose: an open pilot study. Neurosurgery, 1996, Vol. 38, pp. 1096-1103.
(146) Chang, S.M., et al. Phase II study of POLY-ICLC in recurrent anaplastic glioma – A North American Brain Tumor Consortium Study. J. of Clin Oncology, 2006, 24, No. 18A Abstract No. 1550. 
(147) Butowski, N., et al. A phase II clinical trial of poly-ICLC with radiation for adult patients with newly diagnosed supratentorial glioblastoma: a North American Brain Tumor Consortium (NABTC 01-05). J. Neurooncol., 2009, 91: 175-182. 
(148) Rosenfeld, M. R., Chamberlain, M. C., Grossman, S. A., et al. A multiinstitutional phase II study of poly-ICLC and radiotherapy with concurrent and adjuvant temozolomide in adults with newly diagnosed glioblastoma. Neuro Oncol, 2010 Jul 8 (Epub ahead of print). 
(176) Wolchok, J. D., Kluger H., Callahan, M.K., et al. Nivolumab plus ipilimumab in advanced melanoma. New England Journal of Medicine, 2013, 369(2), 122-33. 
(340) Reardon, David A et al. “ReACT: long-term survival from a. randomized phase II study of rindopepimut (CDX-110) plus bevacizumab in relapsed. glioblastoma.” Neuro Oncol 17.suppl 5 (2015): v109. 
(341) Hashimoto, Naoya et al. “Wilms tumor 1 peptide vaccination combined with temozolomide against newly diagnosed glioblastoma: safety and impact on immunological response.” Cancer Immunology, Immunotherapy 64.6 (2015): 707-716. 
(342) Hashimoto, Naoya et al. “IMCT-09 WT1 peptide vaccination for gliomas; survivals, biomarkers and response assessment.” Neuro-Oncology 17.suppl 5 (2015): v109-v109. 
(358) Kato, Shumei, et al. “Hyperprogressors after Immunotherapy: Analysis of Genomic Alterations Associated with Accelerated Growth Rate.” Clinical Cancer Research, vol. 23, no. 15, 2017, pp. 4242–4250., doi:10.1158/1078-0432.ccr-16-3133. 
(359) O’Rourke, Donald M., et al. “A single dose of peripherally infused EGFRvIII-Directed CAR T cells mediates antigen loss and induces adaptive resistance in patients with recurrent glioblastoma.” Science Translational Medicine, vol. 9, no. 399, 2017, doi:10.1126/scitranslmed.aaa0984. 
(360) Brown, C. E., et al. “Bioactivity and Safety of IL13R 2-Redirected Chimeric Antigen Receptor CD8 T Cells in Patients with Recurrent Glioblastoma.” Clinical Cancer Research, vol. 21, no. 18, Sept. 2015, pp. 4062–4072., doi:10.1158/1078-0432.ccr-15-0428.

Fine! I hope you enjoyed reading, I was as faithful as possible. Soon the next chapter! See you soon!