The European Society for Medical Oncology (ESMO) has published a proposed scale that would rank molecular targets for various cancers by how well they can be treated with new or emerging drugs.
The ESMO Scale of Clinical Actionability for Molecular Targets is designed to “harmonize and standardize the reporting and interpretation of clinically relevant genomics data,” according to Joaquin Mateo, MD, PhD, from the Vall d’Hebron Institute of Oncology in Barcelona, Spain, and his fellow members of the ESMO Translational Research and Precision Medicine Working Group.
“A major challenge for oncologists in the clinic is to distinguish between findings that represent proven clinical value or potential value based on preliminary clinical or preclinical evidence from hypothetical gene-drug matches and findings that are currently irrelevant for clinical practice,” they wrote in Annals of Oncology.
The scale groups targets into one of six tiers based on levels of evidence ranging from the gold standard of prospective, randomized clinical trials to targets for which there are no evidence and only hypothetical actionability. The primary goal is to help oncologists assign priority to potential targets when they review results of gene-sequencing panels for individual patients, according to the developers.
Briefly, the six tiers are:
Tier I includes targets that are agreed to be suitable for routine use and a recommended specific drug when a specific molecular alteration is detected. Examples include trastuzumab for human epidermal growth factor receptor 2 (HER2)–positive breast cancer, and inhibitors of epidermal growth factor receptor (EGFR) in patients with non–small cell lung cancer positive for EGFR mutations.
Tier II includes “investigational targets that likely define a patient population that benefits from a targeted drug but additional data are needed.” This tier includes agents that work in the phosphatidylinostiol 3-kinase pathway.
Tier III is similar to Tier II, in that it includes investigational targets that define a patient population with proven benefit from a targeted therapy, but in this case the target is detected in a different tumor type that has not previously been studied. For example, the targeted agent vemurafenib (Zelboraf), which extends survival of patients with metastatic melanomas carrying the BRAF V600E mutation, has only limited activity against BRAF-mutated colorectal cancers.
Tier IV includes targets with preclinical evidence of actionability.
Tier V includes targets with “evidence of relevant antitumor activity, not resulting in clinical meaningful benefit as single treatment but supporting development of cotargeting approaches.” The authors cite the example of PIK3CA inhibitors in patients with estrogen receptor–positive, HER2-negative breast cancers who also have PIK3CA activating mutations. In clinical trials, this strategy led to objective responses but not change outcomes.
The final tier is not Tier VI, as might be expected, but Tier X, with the X in this case being the unknown – that is, alterations/mutations for which there is neither preclinical nor clinical evidence to support their hypothetical use as a drug target.
“This clinical benefit–centered classification system offers a common language for all the actors involved in clinical cancer drug development. Its implementation in sequencing reports, tumor boards, and scientific communication can enable precise treatment decisions and facilitate discussions with patients about novel therapeutic options,” Dr. Mateo and his associates wrote in their conclusion.
The development process was supported by ESMO. Multiple coauthors reported financial relationships with various companies as well as grants/support from other foundations or charities.
SOURCE: Mateo J et al. Ann Oncol. 2018 Aug 21. doi: 10.1093/annonc/mdy263.