Efficacy and Safety of Second-Line 5-Day Dactinomycin in Case of Methotrexate Failure for Gestational Trophoblastic Neoplasia

Abstract

Objective: The objective of this study was to evaluate the characteristics and outcomes of patients treated for gestational trophoblastic neoplasia (GTN) with second-line 5-day dactinomycin after failed first-line 8-day methotrexate.

Methods: From 1999 to 2017, patients with methotrexate resistant GTN treated with second line dactinomycin were identified at the French Trophoblastic Disease Reference Center. Using univariate and multivariate analysis, we identified significant predictive factors of second line dactinomycin failure.

Results: A total of 877 GTN patients were treated with first-line 8-day methotrexate, of which 103 required second-line 5-day dactinomycin for methotrexate failure. Complete response was observed in 78 patients (75.7% [95% confidence interval, 66.3-83.6]; P < 0.0001), whereas 25 needed third-line treatment, 13 for dactinomycin resistance and 12 for post-dactinomycin relapse. Overall survival of patients treated with dactinomycin was 100%. An interval of greater than or equal to 7 months between antecedent pregnancy termination and methotrexate initiation was a predictive factor significantly associated with second-line dactinomycin failure in multivariate analysis (exact odds ratio, 9.17 [95% confidence interval, 1.98-50.70]; P = 0.0029). No grades 4 and 5 adverse effects were experienced and the most common toxicity being grade 1 nausea (14.6%).

Conclusion: Given a 75.7% complete response rate in methotrexate failed low-risk GTN patients treated with second-line dactinomycin and an overall survival rate of 100% after third-line treatment, the use of dactinomycin should be favored as second-line, regardless of human chorionic gonadotropin level at the time of dactinomycin initiation. However, an interval between the termination of the antecedent pregnancy and methotrexate initiation longer than 6 months should encourage considering alternative therapeutic strategies.