The invention features methods for treating cancer in a patient in need thereof by administering eribulin, in combination with one or more PARP inhibitors, and, optionally, a platinum-based antineoplastic drug, and kits therefor. The invention is based in part on the observation that combinations of eribulin mesylate, a PARP inhibitor (e.g., E7449), and, optionally, a platinum-based antineo-plastic drug (e.g., carboplatin), show improved (e.g., synergistic) antitumor effects. Therefore, the present invention features methods of preventing and treating cancer (e.g., homologous recombination (HR)-deficient cancer by the use of combinations of eribulin (e.g., eribulin mesylate) and one or more PARP inhibitors (e.g., E7449 or a pharmaceutically acceptable salt thereof (e.g., the tartrate salt), optionally in combination with a platinum-based antineoplastic drug (e.g., carboplatin).