Feb 4, 2020
ASCO Daily News: Welcome to the ASCO Daily News Podcast. I'm Kara Nyberg. Joining me today is Dr. Emily Bergsland, who is a GI medical oncologist and professor of medicine at the University of California San Francisco. Welcome to the podcast, Dr. Bergsland. We're here to discuss highlights from the 2020 Gastrointestinal Cancer Symposium, for which you served as the program chair. Let's begin with research presented at the meeting that has a direct bearing on clinical practice. Are you and your colleagues going to change your practice based on data coming out of this symposium? And if so, how?
Dr. Bergsland: There were a couple of important advances reported at the meeting that are likely to support new standards of care moving forward. We know that BRAF V600E mutated metastatic colorectal cancer is associated with a very poor prognosis. The BEACON trial was a randomized phase III study of encorafenib plus cetuximab, with or without binimetinib, in previously treated BRAF mutant metastatic colorectal cancer. The BEACON investigators had previously reported that triplet therapy seemed to be better than doublet therapy and improved survival and response rates compared to standard of care treatment.
Dr. Bergsland: At ASCO GI, Dr. Kopetz presented updated results showing that encorafenib plus cetuximab, with or without binimetinib, demonstrated longer maintenance of quality of life, and there was no difference in the quality of life benefit between the doublet and triplet regiments. Furthermore, the median survival is now the same in both groups, 9.3 months, which is significantly better than the 5.9 months seen in control. As a result, the study team is moving forward with doublet therapy instead of triplet therapy, and this filing is now under review by the FDA.
Dr. Bergsland: Updates to the IMbrave150 study were also reported. The IMbrave150 study was a randomized phase III trial of atezolizumab plus bevacizumab versus sorafenib as first line treatment for unresectable hepatocellular carcinoma. As reported at ESMO Asia, atezolizumab improved overall in progression-free survival compared to sorafenib. At ASCO GI, the study team reported that atezolizumab was also associated with significant and consistent benefits in quality of life, functioning, and key symptoms, providing further support for atezolizumab as a new standard of care for untreated hepatocellular carcinoma.
Dr. Bergsland: Finally, the results of a randomized phase II trial of gemcitabine and cisplatin, with or without the PARP inhibitor veliparib, in patients with pancreatic cancer and germline BRCA or PALB2 mutations were presented. Surprisingly, both arms were highly active, with an overall response rate of 74% with triplet therapy and 65% with chemotherapy alone. Olaparib added little benefit, possibly because of heme toxicity limiting the dose delivered. But the high response rate and overall survival of 15 to 16 months in both groups provide support for gem/cis as a new reference treatment for pancreatic cancer in patients with germline BRCA or PALB2 mutations.
ASCO Daily News: Are there any new treatment approaches or agents in development that you're particularly excited about?
Dr. Bergsland: Several presentations focused on biomarkers and liquid biopsies in particular, which I think is where the field is going. The potential value of circulating tumor DNA to guide therapy was highlighted by a study presented at GI ASCO comparing tumor tissue genomic profiling to plasma circulating tumor DNA sequencing using the SCRUM-Japan GI screen and GOZILA combined analysis. Dr. Bergsland: Investigators found that plasma genotyping significantly reduced turnaround time compared to tumor tissue, 35 days versus 12 days, and led to a shorter interval between genotyping and enrollment to match trials.
Dr. Bergsland: There are many prospective clinical trials incorporating circulating tumor DNA underway to validate the use of liquid biopsies to guide treatment, monitor for resistance in GI malignancies, and assess for minimal residual disease after resection, an example of the latter being the COBRA study for stage II colon cancer. Expanding on the idea of blood-based biomarkers, Brian Mulpin described development of a methylation-based cell-free DNA early multi-cancer detection test that can also predict the tissue of origin. Samples were collected as part of the circulating cell-free genome atlas in individuals with and without different cancers.
Dr. Bergsland: Plasma cell-free DNA was subjected to a cross-validated targeted methylation sequencing assay, and the study included both training and validation data sets. The data suggests that a targeted methylation assay from cell-free DNA in the blood may represent a novel non-invasive way of detecting different GI cancers and identifying site of origin. Finally, another interesting finding relates to the fact that identification of the optimal duration and type of adjuvant therapy for patients with resected colon cancer remains a challenge.
Dr. Bergsland: The Immunoscore, which measures immune infiltration in tumors, has emerged as a prognostic marker for patients with localized colon cancer. At ASCO GI, researchers presented an analysis of the Immunoscore in modified FOLFOX-6 treated patients enrolled in the France cohort of the idea study. The results confirm that the Immunoscore is prognostic in these patients. Interestingly, only patients with Immunoscore intermediate or high benefited from six months of FOLFOX treatment compared to three months.
Dr. Bergsland: This was true in both clinical low and high risk subgroups with stage 3 disease. This means that Immunoscore low patients not only have a higher risk of relapse, but they have no obvious benefit from six months of FOLFOX compared to three months. Validation of the results in an independent cohort is planned, but the findings could represent an important step towards improving our ability to individualize adjuvant chemotherapy in patients with resected stage 3 colon cancer.
ASCO Daily News: I know that immunotherapy with checkpoint inhibitors has captured much of the limelight in recent years. Were there any new and notable findings with regard to these therapies?
Dr. Bergsland: Given the IMbrave150 results showing the value of atezo-bev in first line hepatocellular carcinoma, the CheckMate 040 study results are of interest. This was a study of 71 patients with advanced hepatocellular carcinoma randomized to receive nivolumab plus cabozantinib, with or without ipilimumab. Radiographic responses were seen in both groups, 19% with the doublet and 29% with the triplet, and a high disease control rate was observed in both arms. Overall survival after two years of follow-up was at least 22 months in both arms.
Dr. Bergsland: The triplet regimen was associated with more toxicity. Additional studies integrating safety, efficacy, and patient reported outcomes will be needed to determine the relative value of either of these regimens compared to other treatment options for hepatocellular carcinoma. Updated CheckMate 142 data were also presented regarding the use of nivolumab plus low-dose ipilimumab as first line therapy in MSI-high metastatic colorectal cancer. Nivolumab, with or without ipilimumab, is already FDA approved for chemotherapy-resistant MSI-high metastatic colorectal cancer, but the role of combination therapy in the first line setting is unknown.
Dr. Bergsland: CheckMate 142 included 45 previously untreated patients with MSI-high or defective mismatch repair metastatic colorectal cancer. At a median follow-up of 20 months, the overall response rate is 64%. The median overall survival and progression-free survival have not been reached. Combination therapy was well tolerated. This may represent a new first line treatment options for these patients, but longer follow-up is needed to see if the high response rate translates into improved overall survival.
ASCO Daily News: Interesting. Let's move now to earlier stage disease. What advances were discussed related to the treatment of localized GI malignancies?
Dr. Bergsland: There were several presentations focused on the treatment of localized disease, and the theme seemed to be that less may be more. In terms of surgical questions, Dr. Yamada presented preliminary results from the TOP-G trial, a randomized phase II study showing that omentum-preserving gastrectomy is associated with similar short-term outcomes compared to standard of care gastrectomy with omentectomy. The results are not definitive, but support enrollment to an ongoing phase III study, JCOG1711, which would provide a definitive answer on the role of omentectomy.
Dr. Bergsland: In another randomized study, extensive peritoneal lavage did not improve survival compared to surgery alone. This is not recommended for patients undergoing curative gastrectomy for cancer. Finally, researchers from Japan reported on the results of the randomized phase III iPAC study. Primary tumor resection followed by chemotherapy did not improve overall survival compared to chemotherapy alone, thus can't be routinely recommended for colorectal cancer patients with an asymptomatic primary tumor and synchronous unresectable metastases. 87% of patients in the control arm were able to avoid surgery.
Dr. Bergsland: In terms of adjuvant therapy, the RESONANCE trial assessed the use of perioperative SOX chemotherapy in patients with resectable gastric cancer in China. 772 patients were randomly assigned to receive pre- and post-op SOX or adjuvant therapy alone. Neoadjuvant SOX was associated with a higher R0 resection rate, acceptable adverse event profile, and no differences in short-term outcomes. The primary endpoint of three-year disease-free survival has not been reached, though, so this approach remains investigational.
Dr. Bergsland: The results of CCOG-1302 were also presented, a randomized phase II trial assessing CAPOX with continuous versus intermittent use oxaliplatin as adjuvant chemotherapy for stage 2 and 3 colon cancer. CAPOX with planned intermittent oxaliplatin substantially reduced long-term peripheral sensory neuropathy in patients treated with six months of adjuvant therapy, and three-year disease-free survival was similar between groups.
Dr. Bergsland: While intriguing, the results are not practice-changing, as it was a relatively small phase II study. Finally, the Dutch Art-Deco phase III study showed that radiation dose escalation, up to 61 gray to the primary tumor, increased toxicity without increasing local control or overall survival compared to standard dose radiation in patients with esophageal cancer receiving definitive chemoradiation.
ASCO Daily News: The theme for the GI Cancer Symposium this year was accelerating personalized care. Based on research presented at the meeting, what is the field currently doing well, and what can the field be doing better?
Dr. Bergsland: Generally speaking, I think we're making significant progress. One big area of study relates to identification of patients at risk for GI malignancies and modifying cancer screening guidelines accordingly. For example, there was a session on screening in high risk populations. Providers should offer germline testing to any patient with a personal history of pancreatic cancer, since approximately 10% of patients will have an inherited germline mutation.
Dr. Bergsland: Guidelines for screening continue to evolve, but their emerging data support the use of MRI or EUS in mutation carriers. Cholangiocarcinoma rates are increasing globally, and we know that the risk factors vary by location and that type 2 diabetes, a non-alcoholic steatohepatitis, or NASH, may also be contributing. NASH cirrhosis is also a risk factor for hepatocellular carcinoma. Screening practices are evolving as our recommendations for chemo prevention, which may include aspirin and statins in high risk patients.
Dr. Bergsland: Another important area is early onset colon cancer. Colorectal cancer incidence has been declining for several decades in people over the age of 55, but rates in people younger than 55 are increasing at nearly 2% annually, and this has been ongoing since 2006. Younger patients present with more advanced disease and more poorly differentiated tumors. As such, there's an ongoing debate surrounding the optimal age to start screening. Better colorectal cancer risk prediction tools are needed. In the meantime, high risk groups should be prioritized, such as those with a family history of cancer, inflammatory bowel disease, or polyps.
Dr. Bergsland: In addition to improvements in our identification of high risk patients, we're also making great strides in translating advances in our understanding of the molecular underpinnings of GI malignancies to the clinic. The BEACON data are certainly encouraging with respect to the treatment of BRAF V600E metastatic colorectal cancer, and the molecular basis for cholangiocarcinoma is now much better understood, with biomarker-based trials now available for FGFR and IDH-mutant cancers. Despite the many advances presented at the meeting, though, there were a few disappointments, suggesting that there's still a lot of work to be done in the area of biomarker selection and drug development.
Dr. Bergsland: The HALO-109-301 study of nab-paclitaxel/gemcitabine, with or without PEGPH20 in patients with previously untreated hyaluron-high metastatic pancreatic ductal adenocarcinoma was a negative study in a biomarker-selected population. There were also several negative studies in biomarker-unselected patients. The SEQUOIA study of FOLFOX with or without pegylated interleukin-10 as second line therapy for metastatic pancreatic cancer was negative, and there was no benefit in adding ramucirumab, a VEGFR-2 antibody, or merestinib, an oral MET inhibitor, to gem/cis and biomarker on selected metastatic biliary cancer.
Dr. Bergsland: Finally, Australian researchers reported results from the Christoral NET study. Adding chemotherapy to lutetium-177 dotatate in mid-gut neuroendocrine tumors added toxicity without improving efficacy. The results of these studies highlight the ongoing need to identify validated biomarkers that facilitate drug development. This trend is reflected in our clinical trials, with biomarker selected patient populations using tumor-based biomarkers, germline alterations, or circulating tumor DNA increasingly under study.
Dr. Bergsland: Adaptive platform trial designs, such as the platform study of maintenance therapy in gastroesophageal cancer and PanCAN's Precision Promise clinical trial in the first line and second line treatment of metastatic pancreatic cancer, are being incorporated to more efficiently test new therapies by requiring fewer patients to understand if a potential therapy is working and support the testing of multiple investigational therapy simultaneously.
ASCO Daily News: To take things one step farther, how are we doing in terms of actually delivering personalized cancer care? Are we making improvements in patient access to treatment and follow-up?
Dr. Bergsland: The available data suggests we have a long way to go in terms of ensuring equitable access to care across all patients. Disparities in health care delivery were highlighted in several presentations. An analysis of NCDB data revealed that young adults with colorectal cancer in the lowest income and education population had worse overall survival. And regardless of income, patients in metropolitan areas have a lower risk of death, presumably due to greater access to care. Another group analyzed health care in Canada and determined that 1/3 of patients with non-curative gastroesophageal cancer never see a medical oncologist, and only 1/3 of patients receive chemotherapy.
Dr. Bergsland: Care delivery and overall survival showed high geographic variability, with location of residents influencing access to care and overall survival and inferior outcomes for those living further from a cancer center. Dr. Yousef Zafar gave a keynote lecture focused on how advances in precision oncology can be realized equitably across all patient populations, communities, and health care systems. He reminded us that in 2017, only 60% of patients with metastatic colorectal cancer were getting appropriate molecular testing. He also reviewed the costs of cancer care and the impact financial toxicity has on patients.
Dr. Bergsland: Dr. Zafar outlined a need for what he calls "precision delivery of care," which, to be successful, will require collaboration between drug manufacturers, insurance providers, health care providers, and patients, and discussions of clinical benefit toxicity and cost. In the era of precision oncology, novel methods for assessing the value of new drugs are needed, as our reimbursement models that incorporate cost effectiveness. Dr. Zafar stressed that all stakeholders will need to collaborate to find solutions that ensure precision delivery of molecular and immunotherapies to all patients.
ASCO Daily News: Did we learn anything new or unexpected about the pathobiology of GI malignancies at this year's meeting?
Dr. Bergsland: I think one of the most interesting sessions at the meeting was a keynote lecture given by Susan Bullman, a scientist at the Fred Hutchinson Cancer Research Institute. Dr. Bowman reviewed the importance of a microbiome in the human body and in disease. She explained that the naturally occurring microbes in our bodies may confer susceptibility to certain cancers, promote cancer progression, and modulate response to therapeutics.
Dr. Bergsland: For example, tumor associated bacteria are metabolically active and can potentially increase or decrease the activity of certain chemotherapeutic agents, such as gemcitabine. In addition, there is a growing body of evidence that tumor microbiome may modulate the response to immunotherapy. Dr. Bullman's presentation highlighted this exciting new area of study as well as the many unanswered questions in the field, including whether the tumor microbiome itself might be a valid target for cancer therapy. Studies of the microbiome in colon cancer and other diseases are ongoing.
ASCO Daily News: I agree, that was a very fascinating keynote lecture. Given the legalization of marijuana in an increasing number of states, an entire session at the symposium was dedicated to symptom management in the era of legalized marijuana and the opioid crisis. What notable points came out of that session?
Dr. Bergsland: There is great interest in the use of cannabinoids in the face of increased access and legalization in a number of states in the US. The data suggests that patients prefer information about safety and efficacy from their health care providers, but many providers cite inadequate training in this area. Our understanding of the role of these agents is limited by a lack of prospective clinical trials. The strongest evidence for efficacy is in the area of the control of chemotherapy-induced nausea, but it's unclear if cannabinoids impact tumor growth, as most of the studies in this area have been preclinical.
Dr. Bergsland: In terms of practical treatment considerations in the absence of high quality data on strain, dosing, ratios, and potencies of active ingredients and modes of use, a harm reduction model of care is recommended starting with very low doses, with THC-CBD combinations preferred over THC only preparations. Definitive recommendations are further complicated by the lack of information about drug-drug interactions and limited information about quality control. Overall, the panel felt that cannabinoids were not likely to ever replace opioids, so prescribers still need to know how to use opioids in the clinic, keeping an eye out for patients with risk for abuse of these agents and remembering to incorporate a bowel regimen as well as an antiemetic in the first few days.
ASCO Daily News: This was truly an excellent recap. I think we can summarize by saying there was a wealth of research that was presented at the GI Cancer Symposium this year, both positive and negative, that's moving the field forward. It's been a pleasure speaking with you, Dr. Bergsland. Thank you for your time and your insight. To our listeners, thank you for tuning into the ASCO Daily News Podcast. If you are enjoying the content, we encourage you to rate us and review us on Apple Podcast.
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