It is expected that the progression-free survival (PFS) for patients with refractory cancers will decline over subsequent lines of therapy. Patients with refractory metastatic cancer have previously been shown to derive some clinical benefit from comprehensive multiplatform profiling (CMP) of tumor tissue. Data from four independent physician-led prospective and prospective/retrospective studies was pooled in an exploratory manner to determine if PFS was improved when patients were treated with molecular profiling-guided therapies compared to PFS on the prior therapies.
Tumor tissue specimens from 202 patients were submitted for CMP to a certified referral laboratory (Caris Life Sciences, USA) between March 2010 and December 2016. Treatment selections were based on predictive biomarker status associated with agents with potential clinical benefit. Clinical benefit was defined as a PFS ratio (= PFS upon treatment according to CMP/PFS on the prior therapy) ≥ 1.3.
As of December 2016, 157 of 202 (77.8%) profiled patients were treated according to the predictive results, of whom 140 were evaluable. Patients had received a median of three prior therapies (range 1-12). The most common tumor types were breast (n = 35), colorectal (n = 14), non-small cell lung (n = 11) and gastric cancer (n = 9). A median PFS of 120.0 days was observed with CMP-directed therapies compared to 89.5 days for prior therapies (HR = 0.70, p = 0.012). Seventy-three of 140 patients (52%) had a PFS ratio ≥ 1.3. Over 70% of treated patients received chemotherapy alone, while 21% of patients received targeted therapies, either alone or in combination with chemotherapy or hormone therapy.
Contrary to the expected decline in PFS, patients had a better outcome when treated with CMP-guided treatments. This was interestingly driven by the precision use of available chemotherapeutic resources rather than sometimes inaccessible targeted therapies. Further prospective trials in specific tumor types may help to highlight particular patient populations who might benefit most from CMP guidance.
Clinical trial identification
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A. Seeber: Consultant for Caris Life Sciences All other authors have declared no conflicts of interest.