Three new epidithiodiketopiperazines pretrichodermamides D–F (1–3), together with the known N-methylpretrichodermamide B (4) and pretrichodermamide С (5), were isolated from the lipophilic extract of the marine algae-derived fungus Penicillium sp. KMM 4672. The structures of compounds 1–5 were determined based on spectroscopic methods. The absolute configuration of pretrichodermamide D (1) was established by a combination of modified Mosher′s method, NOESY data, and biogenetic considerations. N-Methylpretrichodermamide B (5) showed strong cytotoxicity against 22Rv1 human prostate cancer cells resistant to androgen receptor targeted therapies.