Mario de Lemos - ASCO Summary Report

I attended the annual meeting of the American Society of Clinical Oncology in Chicago in June. Four studies were presented at the plenary session. The first was a pooled analysis of six randomized controlled studies comparing 3 vs. 6 months of adjuvant oxaliplatin-based chemotherapy (FOLFOX or XELOX) for stage III colon cancer. Although the graphical data showed virtually superimposable curves, the upper bound of the 95% confidence interval of the hazard ratio (1.00-1.15) slightly exceeded the pre-defined cut-off to prove non-inferiority (1.00-1.12). This suggests that the difference between 3 vs. 6 months of adjuvant chemotherapy is likely to be small, and the trade-off with toxicities beyond 3 months therapy should be carefully considered. The second study was a single-centre randomized trial comparing cancer patients undergoing routine monitoring vs. patient reported outcomes (PRO) monitored in real-time and recorded for subsequent clinic visit via a web-based interface. In addition to improved quality of life and reduced admission to emergency in the PRO arm, there was also significantly longer overall survival (31.2 vs. 26.0 mos, p=0.03). This interesting finding suggests that pro-active follow-up (e.g., call-back service) may have significant benefits to patients beyond medication compliance, medication errors preventions or symptom control. The third study reported improved overall survival when abiraterone is added to androgen-deprivation therapy in newly diagnosed, high risk (high Gleason score, multiple bone metastases, visceral metastases) metastatic prostate cancer patients. These findings suggest that arbiraterone may be introduced at the earlier spectrum of metastatic disease, before the emergence of castration resistance. Finally, the fourth study reported improved progression free survival and quality of life in patients taking olapirib compared to chemotherapy for progressing metastatic breast cancer after at least two prior lines of standard chemotherapy. Patients were HER2 negative and with germline BRAC mutation. At this point, however, overall survival data are still pending. 
 
I noted several themes from the education sessions and poster abstracts that may have significant impact on oncology pharmacy practice. More and more drug treatments are indicated for diseases with specific genetic or epigenetic mutations. Indeed, pembrolizumab was recently approved for solid tumours with specific mutations, rather than specific tissue or anatomical site. In addition, diseases are also increasingly being defined by mutations, such as the latest WHO classification of CNS tumours. This means that those involved in oncology pharmacy practice would need to become more knowledgeable with the fundamentals of molecular biology of cancer at the genetic level. Making this trend to be even more urgent is the development of liquid biopsy, i.e., detection and quantification of circulating tumour cells and tumour DNAs, usually obtained from plasma. In addition to the recently approved by FDA for EGFR mutation test (Cobas), there were multiple exhibits from vendors who provide liquid biopsy and genomic analysis. Liquid biopsy is easier and cheaper to perform, although the sensitivity needs to be carefully validated because of the much more rare events compared to tissue biopsy. However, it offers the potential for serial testing to monitor therapy response (including evolution of resistance), as well as detection of minimal residual disease at a lower level that previously possible with tissue biopsy. Liquid biopsy may also represent tumour burden of the whole body, rather than the biopsy sites with tissue test alone. 
 
Finally, I came across the exhibit of the Society for Immunotherapy of Cancer which publishes the Journal of Immunotherapy of Cancer, as well as offers patient and health professional resources on their website (www.sitcancer.org). Given the advent of checkpoint inhibitors in multiple tumour sites, this may be a very relevant resource. Finally, there were several sessions and poster abstracts relating to the comparison of the ASCO and the ESMO value frameworks for new cancer treatments, as well as comparison of the pan-Canadian Oncology Drug Review vs. similar national review bodies in other jurisdictions. 
 
Mario de Lemos