Supplementary Figure S4. HFD and diet cycling had minor effects on blood cells in C57BL/6J-Vk*MYC model. Procyte data (A-I)

These results demonstrate the lack of MetAP1 aminopeptidase inhibition by SDX-7539 and TNP-470, and supports the findings regarding selectivity of these compounds for MetAP2.

Contains methods and results from additional experiments

Results of enzyme assays that assessed the potential inhibitory activity of the MetPA2 inhibitor against various enzymes.

Levels of small molecule MetAP2 inhibitors SDX-7539 and TNP-470 in plasma and CSF, used to assess CNS penetration.

Detailed results from each behavioural measurement conducted in rats to assess potential CNS toxicity of SDX-7320.

Supplementary Figure S2. Additional parameters in HFD, diet cycling, and control diet C57BL/6J-Vk*MYC mouse model.

Supplementary Figure S11. xCell analysis of MMRF CoMMpass myeloma patient data demonstrate differences in gene expression profiles between obese and normal weight patients in xCell-derived microenvironment cell type signatures.

Variance in the expression of genes between control and SDX-7320-treated tumor samples is displayed in this graph.

Shows binding assay performance and differential MetAP2 binding of test compounds.

Abstract Background: Androgen receptor pathway inhibitors (ARPIs) improve outcomes for patients with mCRPC. However, development of resistance to ARPIs is a significant clinical issue associated with the emergence of aggressive variant prostate cancer (AVPC), and consequently there is an urgent need for novel, AR pathway-independent therapies. Expression of the metalloprotease methionine aminopeptidase 2 (METAP2) has been correlated with increased mCRPC aggressiveness: high expression was reported in dedifferentiated phenotypes, including NEPC/AVPC. METAP2 regulates protein translation, post-translational modifications and has a clinically validated role inhibiting angiogenesis. METAP2 also has tumor-specific functions coordinating plasticity, vascular mimicry, and hypoxia response. Evexomostat (SDX-7320) is a prodrug of a highly potent, novel METAP2 inhibitor which has completed a phase I safety study in late-stage cancer patients (NCT02743637) and is currently being clinically investigated in patients with metastatic breast cancer (NCT05570253, NCT05455619). It was hypothesized that SDX-7320 would demonstrate anti-tumor efficacy in non-clinical prostate cancer cell-derived xenograft and patient-derived xenograft (PDX) models of ARPI-resistant CRPC and AVPC. Methods: SDX-7320 (12 or 8 mg/kg, subcutaneous dosing, every four days) was tested in NSG mice with LNCaP xenografts in intact, castrated, and CRPC models. SDX-7320 treatment was also evaluated in LuCaP35.CR PDX xenografts in castrate mice alone as well as in combination with enzalutamide following development of resistance to enzalutamide. SDX-7320 was also tested in the LTL545, LUCAP49 and LTL331R (AR-negative, NE-positive) models of AVPC. Tumor growth was assessed and following dissection subsequently analyzed for transcriptomic (RNAseq), protein (Western blot) or histological differences (H&E staining, CD34 IHC). Results: SDX-7320 treatment significantly reduced tumor volume in every model and at every PC stage investigated, alone and in combination with enzalutamide (in enzalutamide-resistant tumors), as well as in the LTL545, LUCAP49 and LTL331R AVPC models. Reduced angiogenesis marker CD34 staining was observed in all tumors from SDX-7320-treated mice. Survival of mice treated with SDX-7320 was significantly enhanced, regardless of model phenotype. Downstream analyses of bulk RNAseq and proteomics showed model-specific changes to plasticity regulators c-Myc and the enhancer of zeste homolog 2 (EZH2) indicating an effect of METAP2 inhibition on prostate cancer cellular differentiation. Conclusions: These results show that inhibition of METAP2 with SDX-7320 is a novel approach to treat ARPI-resistant as well as aggressive forms of prostate cancer warranting immediate clinical translation. Building upon the non-clinical data in models of AVPC presented here, combined with the body of clinical experience with SDX-7320 in past and ongoing clinical trials, planning is underway to conduct a pilot clinical trial with SDX-7320 in men with AVPC. Citation Format: Peter Cornelius, Devina Laurencia, Jennifer H. Gunter, Anja Rockstroh, Benjamin A. Mayes, Pierre Dufour, Bradley J. Carver, James M. Shanahan, Colleen C. Nelson. MetAP2 inhibition by evexomostat (SDX-7320) decreases EZH2 and c-Myc and significantly prolongs survival in enzalutamide-resistant and neuroendocrine prostate cancer models [abstract]. In: Proceedings of AACR Drug Discovery and Development (AACR D3) Conference; 2026 Jul 21-24; Boston, MA. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(14_Suppl):Abstract nr B031.

Detailed information from the x-ray crystallography of SDX-7539 bound to MetAP2 that enabled determination of the co-crystal’s 3D structure.

Results of competition for radioligand binding by SDX-9402 at different receptors, to assess the selectivity of the MetAP2 inhibitor against known drug targets.

Compares the 3D crystal structures of MetAP2 with SDX-7539 bound to that of MetAP2 with TNP-470

Obesity and diabetes are associated with worse prognosis for numerous malignancies. Both insulin resistance and altered levels of adipokines may explain the link between obesity and tumor progression. In preclinical models, METAP2 inhibitors induce weight loss and possess anti-tumor activity, but their effects on obesity-accelerated tumor growth are unknown. Here, we investigated the effects of SDX-7320, a novel polymer-conjugated METAP2 inhibitor, on obesity and obesity-accelerated tumor growth. The anti-obesity and metabolic effects of SDX-7320 were evaluated in diet-induced obese (DIO) mice. Pharmacokinetic-pharmacodynamic relationships for SDX-7320 and the active moiety SDX-7539, a fumagillin class METAP2 inhibitor, were assessed in DIO rats. Anti-tumor efficacy of SDX-7320 was assessed in syngeneic models of obesity-accelerated tumor growth. The anti-tumor efficacy of SDX-7320 and tirzepatide, a weight loss agent, were compared in DIO mice with MC38 tumors. Treatment with SDX-7320 stimulated weight loss in obese mice, increased insulin sensitivity, decreased plasma leptin, and increased plasma adiponectin. Pharmacokinetic-pharmacodynamic analysis showed greater anti-obesity efficacy in response to SDX-7320 than SDX-7539. SDX-7320 significantly attenuated obesity-accelerated tumor growth in three different models (B16F10, EO771, MC38). RNA-Seq analysis of MC38 tumors indicated that SDX-7320 suppressed expression of cell cycle genes (decreased G2M checkpoint and E2F target pathways) and increased expression of host immune response genes (elevated interferon alpha- and gamma-response pathways). In obese mice, SDX-7320 led to significantly greater MC38 tumor growth inhibition than tirzepatide, but caused less weight loss. Plasma metabolomics revealed non-overlapping effects of SDX-7320 and tirzepatide, consistent with different mechanisms of action. Taken together, we have shown for the first time that a METAP2 inhibitor attenuates obesity-accelerated tumor growth. Mechanistically, SDX-7320-mediated tumor growth inhibition likely results from both direct anti-tumor effects (given the observed intratumoral changes in the expression of cell cycle and immune response genes), and indirect effects on the host including weight loss, decreased adipose mass, improved insulin sensitivity and normalization of plasma leptin and adiponectin levels. The fact that SDX-7320 caused greater tumor growth inhibition than tirzepatide, yet caused less weight loss, suggests that direct anti-tumor effects significantly contribute to the anti-tumor activity of SDX-7320.

This table provides details on where each cathepsin enzyme was obtained.

Shows the structures of the PDC, the benzenesulfonate salt form of the physiologically active small molecule, and three test compounds, along with the numbering system utilized for NMR assignment of evexomostat.

Supplementary Figure S3. H&E staining of mouse femurs imaged near the growth plate.

Supplementary Figure S9. Obesity and Fat Mass Expansion also seen in C57BL/6J-5TGM1-TKGFP+/Luc+ mouse cohort 2.