Megan Crumbaker

Lutetium 177 prostate-specific membrane antigen–617 SPECT/CT total tumor volume complete response at 6 weeks was associated with overall survival and may help guide early personalized treatment decisions in metastatic castration-resistant prostate cancer.

Clinical activity and time-to-event endpoints. A, Waterfall plot of the maximum percentage change in PSA from baseline. B, Kaplan–Meier analysis of PSA-PFS. C, Bar chart showing the proportion of patients with prolongation of PSADT at 4 and 12 weeks. D and E, Kaplan–Meier analyses of (D) time to ADT and (E) MFS.

Scatter plots demonstrating significant correlations between the fold change of specific treatment-altered lipids (triacylglycerols, oxidized species, and sphingomyelins) and PSA-PFS time.

Synergistic cytotoxicity of ITRA and CQ in prostate cancer cell lines. A, Dose–response curves showing the activity of ITRA alone (black) or in combination with 5 μmol/L (red) and 10 μmol/L (blue) CQ in a panel of six prostate cancer cell lines after 5 days of treatment. B, Representative three-dimensional synergy maps showing the combined effect of ITRA (0–40 μmol/L) and CQ (5–10 μmol/L) in a panel of six prostate cancer cell lines. C, Histogram plot showing the synergy scores calculated using a Bliss independence model of combination of ITRA and CQ (n = 3 biological replicates, **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, not significant).

Purpose:Biochemical recurrence (BCR) of prostate cancer presents a clinical challenge with limited systemic treatment options beyond androgen deprivation therapy (ADT), which carries significant morbidity. Preclinical data suggest that lysosomal homeostasis, including cholesterol trafficking and pH regulation, is a therapeutic vulnerability in hormone-dependent cancers. We therefore conducted HITMAN-PC, a phase I trial evaluating suba-itraconazole (SI) and hydroxychloroquine (HCQ) in men with BCR.Patients and Methods:The synergy of SI and HCQ was validated in hormone-sensitive and castration-resistant prostate cancer cell lines. The HITMAN-PC trial (NCT03513211) then used a rolling-six design to establish the maximum tolerated dose (MTD) and recommended phase II dose of HCQ with a fixed SI dosage (150 mg twice daily). Secondary endpoints included safety, PSA kinetics [PSA progression-free survival (PFS) and time to ADT], and exploratory pharmacokinetic and lipidomic profiling.Results:Itraconazole showed dose-dependent cytotoxicity, with synergy in LNCaP-derived hormone-sensitive and -resistant lines. Eleven patients were enrolled. Two dose-limiting toxicities at HCQ 600 mg twice daily (grade 3 diarrhea and alanine aminotransferase elevation) defined this level as the MTD with SI 150 mg twice daily. Common adverse events were hypertension, QTc prolongation, diarrhea, and nausea; no grade 4 events occurred. No PSA declines ≥50% were observed although most patients achieved PSA stabilization. The median PSA-PFS, time to ADT, and metastasis-free survival were 5.5, 14.3, and 15.9 months, respectively. Lipidomic profiling revealed 240 treatment-associated lipid changes, with sphingomyelin and triacylglycerol species correlating with PSA-PFS.Conclusions:Despite limited clinical activity overall, the identified lipidomic signatures provide proof of concept for using plasma lipidomics to monitor pharmacodynamic activity in future metabolism-targeted trials.Significance:This study established a safe dose for HCQ and SI but found limited clinical efficacy in prostate cancer. Its significance lies in providing proof of biology that this combination alters systemic lipid metabolism. We identified specific plasma lipid species that correlate with clinical outcomes, highlighting the power of embedded biomarker analysis to generate valuable mechanistic insights and candidate biomarkers, even in the absence of a strong clinical response.

Dose-response curves, 3D synergy maps, and histograms comparing the combined cytotoxic effect of Itraconazole with CQ or HCQ in LNCaP, V16D, and MR-40C cells.

Effect of HCQ + SI treatment on the plasma lipidome. A, Average fold change (posttreatment/baseline) of individual lipid species. B, Scatter plots showing a significant positive correlation between the fold change of key treatment-altered lipid species and PSA-PFS time. C, Heatmap of the fold change (posttreatment/baseline) for lipids that are significantly different between patients with longer (>5 months) vs. shorter (≤5 months) PSA-PFS time. AC, acylcarnitines; AC-OH, hydroxylated acylcarnitines; BA, bile acids; CE, cholesteryl esters; Cer, ceramides; CIP, ceramide phosphates; CoQ10, coenzyme Q10; DE, dehydrocholesteryl esters; deDE, dehydrodesmosteryl esters; DG, diacylglycerols; FFA, free fatty acids; HexCer, hexosylceramides; LPC(O), lysophosphatidylcholines with an O-alkyl chain; LPC, lysophosphatidylcholines; LPE, lysophosphatidylethanolamines; LPI, lysophosphatidylinositols; OxSpecies, oxidized lipid species; PA, phosphatidic acids; PC, phosphatidylcholines; PE, phosphatidylethanolamines; PG, phosphatidylglycerols; PI, phosphatidylinositols; PS, phosphatidylserines; SHexCer, sulfatides (sulfated hexosylceramides); SM/Sph, sphingomyelins; TG(O), ether-linked triacylglycerols; TG, triacylglycerols.

Representative images of LNCaP, V16D, and MR-40C cells treated with Itraconazole alone or in combination with CQ or HCQ for 5 days