Neil H. Bander

Preclinical Development and Clinical Translation of a PSMA-Targeted Docetaxel Nanoparticle with a Differentiated Pharmacological Profile

A targeted nanoparticle containing docetaxel displays antitumor activity in animals and differentiated pharmacological properties in patients with advanced solid tumors. Nanomedicine: From Mice to Men There has been a lot of buzz surrounding nanomedicine. Yet, this word inspires more thoughts of futuristic medicine à la Star Trek than actual visions of the clinic. Indeed, despite the intense research focus on nano-based approaches to everything from cancer to neurodegenerative disease, few nanotechnologies have actually worked in humans. Bridging this obvious translational gap, Hrkach and colleagues have now designed the ideal nanoparticle for targeting and killing cancer cells not only in animals but also in humans. The authors first created a combinatorial library of nanoparticles of varying size, polymer composition and concentration, and processing parameters. The particles contained docetaxel (DTXL), a potent chemotherapeutic, as well as a ligand that selectively targeted prostate-specific membrane antigen, which is present on the surface of prostate cancer cells and on the neovasculature of nonprostate solid tumors. Hrkach et al. showed that the optimized targeted nanoparticle (DTXL-TNP) could release anticancer drug in a controlled manner in vitro as well as in vivo in rats, without any toxicity to the animals. In a mouse model of human prostate cancer, the DTXL-TNPs were also able to slow tumor growth to 26%, whereas the free DTXL could not stop tumors from growing 100% over the 7-week study. Hrkach and coauthors showed that the pharmacokinetic profile of DTXL-TNPs did not differ among mice, rats, and monkeys, which is an important observation when moving new drug delivery platforms from animals to humans. Indeed, their interim results from 12 cancer patients enrolled in a phase 1 clinical trial showed nanoparticle clearance over time similar to the animals. Two of these patients—one with lung metastases, one with tonsillar cancer—even showed signs of tumor shrinkage after being treated with the DTXL-TNPs. After the clinical trial is complete, we will have a better idea of whether these nanoparticles are truly effective at seeking out and killing cancer. In the meantime, we look forward to the day that “nanomedicine” is no longer a buzz word, and is instead routine clinical practice. We describe the development and clinical translation of a targeted polymeric nanoparticle (TNP) containing the chemotherapeutic docetaxel (DTXL) for the treatment of patients with solid tumors. DTXL-TNP is targeted to prostate-specific membrane antigen, a clinically validated tumor antigen expressed on prostate cancer cells and on the neovasculature of most nonprostate solid tumors. DTXL-TNP was developed from a combinatorial library of more than 100 TNP formulations varying with respect to particle size, targeting ligand density, surface hydrophilicity, drug loading, and drug release properties. Pharmacokinetic and tissue distribution studies in rats showed that the NPs had a blood circulation half-life of about 20 hours and minimal liver accumulation. In tumor-bearing mice, DTXL-TNP exhibited markedly enhanced tumor accumulation at 12 hours and prolonged tumor growth suppression compared to a solvent-based DTXL formulation (sb-DTXL). In tumor-bearing mice, rats, and nonhuman primates, DTXL-TNP displayed pharmacokinetic characteristics consistent with prolonged circulation of NPs in the vascular compartment and controlled release of DTXL, with total DTXL plasma concentrations remaining at least 100-fold higher than sb-DTXL for more than 24 hours. Finally, initial clinical data in patients with advanced solid tumors indicated that DTXL-TNP displays a pharmacological profile differentiated from sb-DTXL, including pharmacokinetics characteristics consistent with preclinical data and cases of tumor shrinkage at doses below the sb-DTXL dose typically used in the clinic.

Methotrexate, vinblastine, doxorubicin, and cisplatin for advanced transitional cell carcinoma of the urothelium. Efficacy and patterns of response and relapse

Of 133 patients with advanced urothelial tract cancer given methotrexate (MTX), vinblastine (VBL), Adriamycin (ADR) (doxorubicin; Adria Laboratories, Columbus, OH), and cisplatin (DDP) (M‐VAC regimen), significant tumor regression occurred in 72% ± 8% of 121 with transitional cell carcinoma (TCC) evaluable for response. Complete remission (CR) was achieved in 36% ± 9% of patients, of whom 11% required the addition of surgical resection of residual disease. Although 68% of CR patients have relapsed, CR median survival will exceed 38 months compared with 11 months for partial (36%) and minor (6%) responders, and 8 months for nonresponders: 2‐year and 3‐year survivals were 68% and 55%, respectively, versus 0% to 7% for the remaining patients. Sixteen percent of responders developed brain lesions, half of whom had no systemic relapse at the time of progression. Three patients with non‐TCC histologies did not respond. In 32 patients who had pathologic restaging, the clinical (T) understaging (T < pathologic [P] restaging) error was 35%. Although all metastatic sites showed evidence of tumor regression, CR was noted more frequently in lung, in intraabdominal lymph nodes and masses, and in bone (24% to 35%); the rate for hepatic lesions was 15%. There were 52% of 21 N3–4Mo patients who achieved CR versus 33% of 100 with No‐+M+ lesions. Toxicity was significant with 4 (3%) drug‐related deaths, 25% incidence of nadir sepsis, 58% ⩾ 3+ myelosuppression, and 49% with mucositis. Responsiveness of metastasis in various sites, patterns of relapse, and the usefulness of the new CR response criteria are reported, as is the current status of cisplatin and methotrexate combination regimens. Cancer 64:2448–2458, 1989.

Phase I Trial of 177Lutetium-Labeled J591, a Monoclonal Antibody to Prostate-Specific Membrane Antigen, in Patients With Androgen-Independent Prostate Cancer

PURPOSE To determine the maximum tolerated dose (MTD), toxicity, human anti-J591 response, pharmacokinetics (PK), organ dosimetry, targeting, and biologic activity of (177)Lutetium-labeled anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 ((177)Lu-J591) in patients with androgen-independent prostate cancer (PC). PATIENTS AND METHODS Thirty-five patients with progressing androgen-independent PC received (177)Lu-J591. All patients underwent (177)Lu-J591 imaging, PK, and biodistribution determinations. Patients were eligible for up to three retreatments. RESULTS Thirty-five patients received (177)Lu-J591, of whom 16 received up to three doses. Myelosuppression was dose limiting at 75 mCi/m(2), and the 70-mCi/m(2) dose level was determined to be the single-dose MTD. Repeat dosing at 45 to 60 mCi/m(2) was associated with dose-limiting myelosuppression; however, up to three doses of 30 mCi/m(2) could be safely administered. Nonhematologic toxicity was not dose limiting. Targeting of all known sites of bone and soft tissue metastases was seen in all 30 patients with positive bone, computed tomography, or magnetic resonance images. No patient developed a human anti-J591 antibody response to deimmunized J591 regardless of number of doses. Biologic activity was seen with four patients experiencing >or= 50% declines in prostate-specific antigen (PSA) levels lasting from 3+ to 8 months. An additional 16 patients (46%) experienced PSA stabilization for a median of 60 days (range, 1 to 21+ months). CONCLUSION The MTD of (177)Lu-J591 is 70 mCi/m(2). Multiple doses of 30 mCi/m(2) are well tolerated. Acceptable toxicity, excellent targeting of known sites of PC metastases, and biologic activity in patients with androgen-independent PC warrant further investigation.

Taxane-Induced Blockade to Nuclear Accumulation of the Androgen Receptor Predicts Clinical Responses in Metastatic Prostate Cancer

Prostate cancer progression requires active androgen receptor (AR) signaling which occurs following translocation of AR from the cytoplasm to the nucleus. Chemotherapy with taxanes improves survival in patients with castrate resistant prostate cancer (CRPC). Taxanes induce microtubule stabilization, mitotic arrest, and apoptotic cell death, but recent data suggest that taxanes can also affect AR signaling. Here, we report that taxanes inhibit ligand-induced AR nuclear translocation and downstream transcriptional activation of AR target genes such as prostate-specific antigen. AR nuclear translocation was not inhibited in cells with acquired β-tubulin mutations that prevent taxane-induced microtubule stabilization, confirming a role for microtubules in AR trafficking. Upon ligand activation, AR associated with the minus-end-microtubule motor dynein, thereby trafficking on microtubules to translocate to the nucleus. Analysis of circulating tumor cells (CTC) isolated from the peripheral blood of CRPC patients receiving taxane chemotherapy revealed a significant correlation between AR cytoplasmic sequestration and clinical response to therapy. These results indicate that taxanes act in CRPC patients at least in part by inhibiting AR nuclear transport and signaling. Further, they suggest that monitoring AR subcellular localization in the CTCs of CRPC patients might predict clinical responses to taxane chemotherapy.

Capture of circulating tumor cells from whole blood of prostate cancer patients using geometrically enhanced differential immunocapture (GEDI) and a prostate-specific antibody.

Geometrically enhanced differential immunocapture (GEDI) and an antibody for prostate-specific membrane antigen (PSMA) are used for high-efficiency and high-purity capture of prostate circulating tumor cells from peripheral whole blood samples of castrate-resistant prostate cancer patients.

Phase I Trial of Yttrium-90—Labeled Anti—Prostate-Specific Membrane Antigen Monoclonal Antibody J591 for Androgen-Independent Prostate Cancer

PURPOSE To determine the maximum-tolerated dose (MTD), toxicity, human antihuman antibody (HAHA) response, pharmacokinetics, organ dosimetry, targeting, and preliminary efficacy of yttrium-90-labeled anti-prostate-specific membrane antigen monoclonal antibody J591 ((90)Y-J591) in patients with androgen-independent prostate cancer (PC). PATIENTS AND METHODS Patients with androgen-independent PC and evidence of disease progression received indium-111-J591 for pharmacokinetic and biodistribution determinations followed 1 week later by (90)Y-J591 at five dose levels: 5, 10, 15, 17.5, and 20 mCi/m(2). Patients were eligible for up to three re-treatments if platelet and neutrophil recovery was satisfactory. RESULTS Twenty-nine patients with androgen-independent PC received (90)Y-J591, four of whom were re-treated. Dose limiting toxicity (DLT) was seen at 20 mCi/m(2), with two patients experiencing thrombocytopenia with non-life-threatening bleeding episodes requiring platelet transfusions. The 17.5-mCi/m(2) dose level was determined to be the MTD. No re-treated patients experienced DLT. Nonhematologic toxicity was not dose limiting. Targeting of known sites of bone and soft tissue metastases was seen in the majority of patients. No HAHA response was seen. Antitumor activity was seen, with two patients experiencing 85% and 70% declines in prostate-specific antigen (PSA) levels lasting 8 and 8.6 months, respectively, before returning to baseline. Both patients had objective measurable disease responses. An additional six patients (21%) experienced PSA stabilization. CONCLUSION The recommended dose for (90)Y-J591 is 17.5 mCi/m(2). Acceptable toxicity, excellent targeting of known sites of PC metastases, and biologic activity in patients with androgen-independent PC warrant further investigation of (90)Y-J591 in the treatment of patients with PC.

89Zr-DFO-J591 for ImmunoPET of Prostate-Specific Membrane Antigen Expression In Vivo

89Zr (half-life, 78.41 h) is a positron-emitting radionuclide that displays excellent potential for use in the design and synthesis of radioimmunoconjugates for immunoPET. In the current study, we report the preparation of 89Zr-desferrioxamine B (DFO)-J591, a novel 89Zr-labeled monoclonal antibody (mAb) construct for targeted immunoPET and quantification of prostate-specific membrane antigen (PSMA) expression in vivo. Methods: The in vivo behavior of 89Zr-chloride, 89Zr-oxalate, and 89Zr-DFO was studied using PET. High-level computational studies using density functional theory calculations have been used to investigate the electronic structure of 89Zr-DFO and probe the nature of the complex in aqueous conditions. 89Zr-DFO-J591 was characterized both in vitro and in vivo. ImmunoPET in male athymic nu/nu mice bearing subcutaneous LNCaP (PSMA-positive) or PC-3 (PSMA-negative) tumors was conducted. The change in 89Zr-DFO-J591 tissue uptake in response to high- and low-specific-activity formulations in the 2 tumor models was measured using acute biodistribution studies and immunoPET. Results: The basic characterization of 3 important reagents—89Zr-chloride, 89Zr-oxalate, and the complex 89Zr-DFO—demonstrated that the nature of the 89Zr species dramatically affects the biodistribution and pharmacokinetics. Density functional theory calculations provide a rationale for the observed high in vivo stability of 89Zr-DFO–labeled mAbs and suggest that in aqueous conditions, 89Zr-DFO forms a thermodynamically stable, 8-coordinate complex by coordination of 2 water molecules. 89Zr-DFO-J591 was produced in high radiochemical yield (>77%) and purity (>99%), with a specific activity of 181.7 ± 1.1 MBq/mg (4.91 ± 0.03 mCi/mg). In vitro assays demonstrated that 89Zr-DFO-J591 had an initial immunoreactive fraction of 0.95 ± 0.03 and remained active for up to 7 d. In vivo biodistribution experiments revealed high, target-specific uptake of 89Zr-DFO-J591 in LNCaP tumors after 24, 48, 96, and 144 h (34.4 ± 3.2 percentage injected dose per gram [%ID/g], 38.0 ± 6.2 %ID/g, 40.4 ± 4.8 %ID/g, and 45.8 ± 3.2 %ID/g, respectively). ImmunoPET studies also showed that 89Zr-DFO-J591 provides excellent image contrast, with tumor-to-muscle ratios greater than 20, for the delineation of LNCaP xenografts between 48 and 144 h after administration. Conclusion: These studies demonstrate that 89Zr-DFO–labeled mAbs show exceptional promise as radiotracers for immunoPET of human cancers. 89Zr-DFO-J591 displays high tumor–to–background tissue contrast in immunoPET and can be used to delineate and quantify PSMA-positive prostate tumors in vivo.

Superparamagnetic Iron Oxide Nanoparticle–Aptamer Bioconjugates for Combined Prostate Cancer Imaging and Therapy

ThemajorshortcomingofCombidexisitsinabilitytodetectPCadiseaseoutsideofthelymphnodes.Herein, we report the development of a novel, multifunc-tional, thermally cross-linked SPION (TCL-SPION) that can bothdetect PCa cells, and deliver targeted chemotherapeuticagents directly to the PCa cells. We previously reported theuseoftheA10RNAaptamer (Apt), which bindstheextracellu-lar domain of the prostate-specific membrane antigen (PSMA),to engineer targeted nanoparticles for PCa therapy and imag-ing.

Antigens recognized by autologous antibody in patients with renal-cell carcinoma

The screening of cDNA expression libraries derived from human tumors with autologous antibody (SEREX) is a powerful method for defining the structure of tumor antigens recognized by the humoral immune system. Sixty‐five distinct antigens (NY‐REN‐1 to NY‐REN‐65) reactive with autologous IgG were identified by SEREX analysis of 4 renal cancer patients and were characterized in terms of cDNA sequence, mRNA expression pattern, and reactivity with allogeneic sera. REN‐9, ‐10, ‐19, and ‐26 have a known association with human cancer. REN‐9 (LUCA‐15) and REN‐10 (gene 21) map to the small cell lung cancer tumor suppressor gene locus on chromosome 3p21.3. REN‐19 is equivalent to LKB1/STK11, a gene that is defective in Peutz‐Jeghers syndrome and cancer. REN‐26 is encoded by the bcr gene involved in the [t(9:22)] bcr/abl translocation. Genes encoding 3 of the antigens in the series showed differential mRNA expression; REN‐3 displays a pattern of tissue‐specific isoforms, and REN‐21 and REN‐43 are expressed at a high level in testis in comparison to 15 other normal tissues. The other 62 antigens were broadly expressed in normal tissues. With regard to immunogenicity, 20 of the 65 antigens reacted only with autologous sera. Thirty‐three antigens reacted with sera from normal donors, indicating that their immunogenicity is not restricted to cancer. The remaining 12 antigens reacted with sera from 5–25% of the cancer patients but not with sera from normal donors. Seventy percent of the renal cancer patients had antibodies directed against one or more of these 12 antigens. Our results demonstrate the potential of the SEREX approach for the analysis of the humoral immune response against human cancer. Int. J. Cancer 83:456–464, 1999.

The oestrogen receptor alpha-regulated lncRNA NEAT1 is a critical modulator of prostate cancer

The androgen receptor (AR) plays a central role in establishing an oncogenic cascade that drives prostate cancer progression. Some prostate cancers escape androgen dependence and are often associated with an aggressive phenotype. The oestrogen receptor alpha (ERα) is expressed in prostate cancers, independent of AR status. However, the role of ERα remains elusive. Using a combination of chromatin immunoprecipitation (ChIP) and RNA-sequencing data, we identified an ERα-specific non-coding transcriptome signature. Among putatively ERα-regulated intergenic long non-coding RNAs (lncRNAs), we identified nuclear enriched abundant transcript 1 (NEAT1) as the most significantly overexpressed lncRNA in prostate cancer. Analysis of two large clinical cohorts also revealed that NEAT1 expression is associated with prostate cancer progression. Prostate cancer cells expressing high levels of NEAT1 were recalcitrant to androgen or AR antagonists. Finally, we provide evidence that NEAT1 drives oncogenic growth by altering the epigenetic landscape of target gene promoters to favour transcription.