Add-on bevacizumab can prevent early clinical deterioration and prolong survival in newly diagnosed partially resected glioblastoma patients with a poor performance status

Abstract

Purpose

The AVAglio trial established the beneficial effect of add-on bevacizumab (BEV) for the treatment of newly diagnosed glioblastomas (nd-GBMs) that led to the approval of BEV for the treatment of these patients in Japan. However, the rationality of using BEV as a first-line treatment for nd-GBMs remains controversial. The purpose of this study was to analyze the outcomes of a case series of nd-GBM patients.

Patients and methods

The outcomes of 69 nd-GBM patients treated after 2006 were retrospectively analyzed. Clinical and genetic analyses were performed, and estimates of progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan–Meier method. Since add-on BEV therapy was only used for partially resected GBMs (pr-GBMs) after its approval in 2013, the patients were subdivided into 3 treatment groups: Type I, partial removal with temozolomide (TMZ)/BEV and concurrent radiotherapy (CCRT); Type II, partial removal with TMZ and CCRT; and Type III, gross total removal with TMZ and CCRT.

Results

The PFS rate of Type I patients was significantly higher than that of Type II patients (P=0.014), but comparable to that of Type III patients. Differences in OS rates between Type I and Type II patients were less apparent (P=0.075), although the median OS of Type I patients was ~8 months higher than that of Type II patients (17.4 vs 9.8 months, respectively). The clinical deterioration rate during initial treatment was significantly (P=0.024) lower in Type I than in Type II patients (7.7% vs 47.4%, respectively). Differences in OS rates between Type I and Type II patients with a poor performance status (PS) were significant (P=0.017).

Conclusion

Our findings suggest that add-on BEV can prevent early clinical deterioration of pr-GBM patients and contribute to a prolonged survival, especially for those with a poor PS.

Keywords:

• bevacizumab
• glioblastoma
• performance status
• survival
• unresectable

Supplementary materials

Detection of hot spot mutations in glioblastoma tissues

Mutation detection of the IDH1 (codon 132), IDH2 (codon 172), BRAF (codon 600), and H3F3A (codons 27 and 34) genes was performed by high-resolution melt (HRM) analysis and subsequent Sanger sequencing. Primer sequences for the amplification of genomic DNA were designed using Primer3Plus¹ (http://bioinformatics.nl/cgi-bin/primer3plus/primer3plus.cgi/). In silico polymerase chain reaction (PCR) applications (http://genome.ucsc.edu/cgi-bin/hgPcr) were used to verify the theoretical specificity of the forward and reverse primers. Details of the primer sequences and their amplicon sizes are provided in Table S1. Whole HRM reactions were prepared using 16.6 ng of DNA, 7.47 pmol/L of each of the forward and reverse primers, and 10 µL of MeltDoctor HRM Master Mix (Applied Biosystems^®, Tokyo, Japan) in a total volume of 20 µL, according to the manufacturer’s protocol. An ABI 7,500 Fast Real-Time PCR System (Applied Biosystems) was used for amplification. The cycling conditions were as follows: 1) an initial denaturation step at 95°C for 10 minutes; 2) 40 cycles of 95°C for 15 seconds, followed by 60°C for 1 minute; and 3) a dissociation cycle of 95°C for 15 seconds, followed by 60°C for 1 minute, and 95°C for 15 seconds. Mutations were determined according to our previous study.² Thereafter, HRM products were purified using ExoSap-IT (Affymetrix Inc., Santa Clara, CA, USA) for mutation genotyping. Cycle sequencing was performed using BigDye^® Terminator v3.1 Cycle Sequencing Kit (Applied Biosystems). After purification of the products, electrophoresis and analysis were conducted using an ABI PRISM^® 310 Genetic Analyzer (Applied Biosystems).

PCR and sequencing of the TERT promoter were performed according to a previous study with slight modifications.³ In our study, we designed the following oligonucleotide primers using Primer3Plus:¹ 5′-GGCCGATTCGACCTCTCT-3′and 5′-CAGCGCTGCCTGAAACTC-3′. PCR reactions were performed in 10 µL volumes containing ~20 ng of DNA, 0.1 µL of TaKaRa LA Taq^® DNA polymerase (TaKaRa Bio Inc., Shiga, Japan), 5 µL of 2× GC Buffer I, 1.6 µL of the deoxyribonucleoside triphosphate mixture (2.5 mM of each dNTP), and 1.67 µL of each of the primers (2 µM). The cycling conditions were as follows: 1) an initial denaturation step at 95°C for 5 minutes; 2) 35 cycles of 94°C for 30 seconds, followed by 62°C for 30 seconds, and 72°C for 30 seconds; and 3) a final elongation step at 72°C for 7 minutes. The PCR products were gel purified and sequenced on an ABI 310^® PRISM Genetic Analyzer (Applied Biosystems).

Table S1 Primer sequences

References

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Acknowledgments

The authors wish to thank Dr Hiroshi Muratani (Ando Hospital, Fukuoka, Japan) for his provision of clinical data and Ms Fumie Doi (Kyushu University) for her technical assistance. This work was supported by a Japanese Society for the Promotion of Science Grants-in-Aid for Scientific Research (KAKENHI) Award (Grant No 26462185, 25293311, 15K15529 and 16K10779).

Disclosure

The authors report no conflicts of interest in this work.