Bevacizumab for progressive glioblastoma multiforme: a case of treading the tightrope

Abstract

Until March 2013, Bevacizumab had been funded through the National Cancer Drugs Fund (CDF) for the treatment of recurrent/progressive Glioblastoma multiforme (GBM). Although the CDF concluded at the time that there was insufficient evidence around the effectiveness of the Bevacizumab on overall survival and quality of life, there is evidence that a small number of individual patients may significantly benefit from it. We present a case of a 40-year old man with GBM (IDH-1 wild-type, MGMT <10% methylated) who, following surgical debulking, was treated as per the Stupp regime. 2 months after completing adjuvant Temozolamide, he developed clinical and radiological progression. He was commenced on Bevacizumab and Irinotecan, which at the time was funded through the CDF. Following 4 cycles of treatment, his symptoms resolved, and at minimum, good partial radiological response was achieved. After 34 cycles the Irinotecan was stopped due to debilitating diarrhoea. After 44 cycles, the Bevacizumab was suspended for 4 weeks because the patient developed a perianal abscess and fistula, which were treated surgically with incision, drainage, and Seton insertion. At this point, discussions with the patient regarding stopping Bevacizumab were held, and his choice was to continue despite the risks. To date (March 2017) he has received 101 cycles of Bevacizumab, equating to 4 years of treatment, with no evidence of radiological or clinical progression. He has developed mild hypertension, for which he has declined antihypertensive treatment. His perianal fistula has completely healed. To our knowledge, this patient is one of the longest survivors on Bevacizumab given at progression. This case has posed, and still poses, important questions in relation to patient choice and risk-benefit conversations; in particular relating to the potential risks of protracted treatment vs its benefit, and the possibility of “drug holidays”.