A lot of new data have emerged over the last 2-3 years that have addressed the concept of “maintenance therapy” for patients with advanced NSCLC (see Dr. Socinski’s excellent podcast for a general review). The basic idea is that a patient is treated with first line chemo-based treatment, with or without the angiogenesis in inhibitor Avastin (bevacizumab), and the fortunate majority have some degree of tumor shrinkage or at least stable disease. The degree of benefit from each subsequent cycle of chemotherapy tends to decrease with further treatments, so you reach a point of diminishing returns for an often-challenging two or three-drug combination. While the well-established standard up until a few years ago had been to stop first line therapy and observe a patient for progression before initiating second line treatment, several trials in the last few years have demonstrated that lighter ongoing maintenance therapy, more to suppress the cancer at its current state of prior response and non-progression than to markedly shrink the cancer further, provides a very significant improvement in progression-free survival, and a less clear but at least strongly suggested overall survival benefit (the trials showing a significant improvement in overall survival have some substantial flaws).

There are two basic concepts of maintenance therapy: one is switch maintenance therapy, in which someone stops all of the first line drugs and switches to a new therapy to maintain the response. It has the theoretical advantage of treating the cancer from a new angle, with an agent that the remaining cancer has not had the opportunity to develop resistance to. The approvals of both Alimta (pemetrexed) and Tarceva (erlotinib) as maintenance therapies are based on this concept. In contrast, continuation maintenance therapy is when one or more of the agents from the first line setting is continued after a fixed number of cycles of first line therapy. We haven’t had much data on this concept with modern chemo approaches, but this year at ASCO, a couple of interesting trials were presented that provided some additional insight on this approach (though oncologists often use this approach with Avastin and Alimta, we haven’t seen data that demonstrate continuation maintenance with these agents is beneficial).

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