Review of phase II trial designs used in studies of molecular targeted agents: outcomes and predictors of success in phase III

PURPOSE

Because the appropriate design and end points for phase II evaluation of targeted anticancer agents are unclear, we undertook a review of recent reports of phase II trials of targeted agents to determine the types of designs used, the planned end points, the outcomes, and the relationship between trial outcomes and regulatory approval.

METHODS

We retrieved reports of single-agent phase II trials in six solid tumors for 19 targeted drugs. For each, we abstracted data regarding planned design and actual results. Response rates were examined for any relationship to eventual success of the agents, as determined by US Food and Drug Administration approval for at least one indication.

RESULTS

Eighty-nine trials were identified. Objective response was the primary or coprimary end point in the majority of trials (61 of 89 trials). Fourteen reports were of randomized studies generally evaluating different doses of agents, not as controlled experiments. Enrichment for target expression was uncommon. Objective responses were seen in 38 trials; in 19 trials, response rates were more than 10%, and in eight, they were more than 20%. Agents with high response rates tended to have high nonprogression rates; renal cell carcinoma was the exception to this. Higher overall response rates were predictive of regulatory approval in the tumor types reviewed (P = .005).

CONCLUSION

In practice, phase II design for targeted agents is similar to that for cytotoxics. Objective response seems to be a useful end point for screening new targeted agents because, in our review, its observation predicted for eventual success. Improvements in design are recommended, as is more frequent inclusion of biological questions as part of phase II trials.

Randomized phase III study of matrix metalloproteinase inhibitor BMS-275291 in combination with paclitaxel and carboplatin in advanced non-small-cell lung cancer: National Cancer Institute of Canada-Clinical Trials Group Study BR.18

PURPOSE

To determine whether BMS-275291, a broad-spectrum matrix metalloproteinase inhibitor (MMPI), added to systemic chemotherapy improved survival in advanced non-small-cell lung cancer (NSCLC). In early phase studies, BMS- 275291 was not associated with dose-limiting joint toxicity seen with other MMPIs.

PATIENTS AND METHODS

Chemotherapy-naive patients with stage IIIB/IV NSCLC, performance status (PS) 0 to 2, and adequate organ function were eligible. All patients received paclitaxel 200 mg/m2 plus carboplatin (area under the curve, 6 mg/mL-min) intravenously every 21 days for up to 8 cycles, and were randomly assigned to receive BMS-275291, 1,200 mg orally daily, or placebo until disease progression. The primary study end point was survival (OS); secondary end points included progression-free survival (PFS), response rates (RR), toxicity, and quality of life.

RESULTS

From 2000 to 2002, 774 patients were randomly assigned. Pretreatment characteristics were well balanced between arms: median age, 61 years; male sex, 73%; stage IV, 79%; PS 0 to 1, 88%. Interim safety analysis revealed no survival advantage and increased toxicity in the experimental arm, and study treatment was stopped. Median OS, PFS and RR in the final analysis in the BMS-275291 arm were 8.6 months, 4.9 months, and 25.8% respectively, and in the control arm 9.2 months, 5.3 months, 33.7%. Toxicity was significantly higher in the BMS-275291 arm, including flu-like symptoms, rash, hypersensitivity reactions (8.6% v 2.4%), and febrile neutropenia (9.7% v 5.5%).

CONCLUSION

BMS-275291 added to chemotherapy increases toxicity and does not improve survival in advanced NSCLC.