Matthew I. Milowsky

Genome Sequencing Identifies a Basis for Everolimus Sensitivity

Tumor genome sequencing reveals the molecular basis of a patient’s unexpected and dramatic response to a cancer drug. Cancer drugs often induce dramatic responses in a small minority of patients. We used whole-genome sequencing to investigate the genetic basis of a durable remission of metastatic bladder cancer in a patient treated with everolimus, a drug that inhibits the mTOR (mammalian target of rapamycin) signaling pathway. Among the somatic mutations was a loss-of-function mutation in TSC1 (tuberous sclerosis complex 1), a regulator of mTOR pathway activation. Targeted sequencing revealed TSC1 mutations in about 8% of 109 additional bladder cancers examined, and TSC1 mutation correlated with everolimus sensitivity. These results demonstrate the feasibility of using whole-genome sequencing in the clinical setting to identify previously occult biomarkers of drug sensitivity that can aid in the identification of patients most likely to respond to targeted anticancer drugs.

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.

Intrinsic subtypes of high-grade bladder cancer reflect the hallmarks of breast cancer biology

Significance The identification of molecular subtype heterogeneity in breast cancer has allowed a deeper understanding of breast cancer biology. We present evidence that there are two intrinsic subtypes of high-grade bladder cancer, basal-like and luminal, which reflect the hallmarks of breast biology. Moreover, we have developed an accurate gene set predictor of molecular subtype, the BASE47, that should allow the incorporation of subtype stratification into clinical trials. Further clinical, etiologic, and therapeutic response associations will be of interest in future investigations. We sought to define whether there are intrinsic molecular subtypes of high-grade bladder cancer. Consensus clustering performed on gene expression data from a meta-dataset of high-grade, muscle-invasive bladder tumors identified two intrinsic, molecular subsets of high-grade bladder cancer, termed “luminal” and “basal-like,” which have characteristics of different stages of urothelial differentiation, reflect the luminal and basal-like molecular subtypes of breast cancer, and have clinically meaningful differences in outcome. A gene set predictor, bladder cancer analysis of subtypes by gene expression (BASE47) was defined by prediction analysis of microarrays (PAM) and accurately classifies the subtypes. Our data demonstrate that there are at least two molecularly and clinically distinct subtypes of high-grade bladder cancer and validate the BASE47 as a subtype predictor. Future studies exploring the predictive value of the BASE47 subtypes for standard of care bladder cancer therapies, as well as novel subtype-specific therapies, will be of interest.

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.

Prevalence and Co-Occurrence of Actionable Genomic Alterations in High-Grade Bladder Cancer

PURPOSE We sought to define the prevalence and co-occurrence of actionable genomic alterations in patients with high-grade bladder cancer to serve as a platform for therapeutic drug discovery. PATIENTS AND METHODS An integrative analysis of 97 high-grade bladder tumors was conducted to identify actionable drug targets, which are defined as genomic alterations that have been clinically validated in another cancer type (eg, BRAF mutation) or alterations for which a selective inhibitor of the target or pathway is under clinical investigation. DNA copy number alterations (CNAs) were defined by using array comparative genomic hybridization. Mutation profiling was performed by using both mass spectroscopy-based genotyping and Sanger sequencing. RESULTS Sixty-one percent of tumors harbored potentially actionable genomic alterations. A core pathway analysis of the integrated data set revealed a nonoverlapping pattern of mutations in the RTK-RAS-RAF and phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathways and regulators of G1-S cell cycle progression. Unsupervised clustering of CNAs defined two distinct classes of bladder tumors that differed in the degree of their CNA burden. Integration of mutation and copy number analyses revealed that mutations in TP53 and RB1 were significantly more common in tumors with a high CNA burden (P < .001 and P < .003, respectively). CONCLUSION High-grade bladder cancer possesses substantial genomic heterogeneity. The majority of tumors harbor potentially tractable genomic alterations that may predict for response to target-selective agents. Given the genomic diversity of bladder cancers, optimal development of target-specific agents will require pretreatment genomic characterization.

Vascular Targeted Therapy With Anti–Prostate-Specific Membrane Antigen Monoclonal Antibody J591 in Advanced Solid Tumors

PURPOSE Based on prostate-specific membrane antigen (PSMA) expression on the vasculature of solid tumors, we performed a phase I trial of antibody J591, targeting the extracellular domain of PSMA, in patients with advanced solid tumor malignancies. This was a proof-of-principle evaluation of PSMA as a potential neovascular target. The primary end points were targeting,toxicity, maximum-tolerated dose, pharmacokinetics (PK), and human antihuman antibody (HAHA) response. PATIENTS AND METHODS Patients had advanced solid tumors previously shown to express PSMA on the neovasculature. They received 111Indium (111ln)-J591 for scintigraphy and PK, followed 2 weeks later by J591 with a reduced amount of 111In for additional PK measurements. J591 dose levels were 5, 10, 20, 40, and 80 mg. The protocol was amended for six weekly administrations of unchelated J591. Patients with a response or stable disease were eligible for re-treatment. Immunohistochemistry assessed PSMA expression in tumor tissues. RESULTS Twenty-seven patients received monoclonal antibody (mAb) J591. Treatment was well tolerated. Twenty (74%) of 27 patients had at least one area of known metastatic disease targeted by 111In-J591, with positive imaging seen in patients with kidney, bladder, lung, breast, colorectal, and pancreatic cancers, and melanoma. Seven of 10 patient specimens available for immunohistochemical assessment of PSMA expression in tumor-associated vasculature demonstrated PSMA staining. No HAHA response was seen. Three patients of 27 with stable disease received re-treatment. CONCLUSION Acceptable toxicity and excellent targeting of known sites of metastases were demonstrated in patients with multiple solid tumor types, highlighting a potential role for the anti-PSMA antibody J591 as a vascular-targeting agent.

Phase II Study of Lutetium-177–Labeled Anti-Prostate-Specific Membrane Antigen Monoclonal Antibody J591 for Metastatic Castration-Resistant Prostate Cancer

Purpose: To assess the efficacy of a single infusion of radiolabeled anti-prostate-specific membrane antigen (PSMA) monoclonal antibody J591 (lutetium-177; 177Lu) by prostate-specific antigen (PSA) decline, measurable disease response, and survival. Experimental Design: In this dual-center phase II study, two cohorts with progressive metastatic castration-resistant prostate cancer received one dose of 177Lu-J591 (15 patients at 65 mCi/m2, 17 at 70 mCi/m2) with radionuclide imaging. Expansion cohort (n = 15) received 70 mCi/m2 to verify response rate and examine biomarkers. Results: Forty-seven patients who progressed after hormonal therapies (55.3% also received prior chemotherapy) received 177Lu-J591. A total of 10.6% experienced ≥50% decline in PSA, 36.2% experienced ≥30% decline, and 59.6% experienced any PSA decline following their single treatment. One of 12 with measurable disease experienced a partial radiographic response (8 with stable disease). Sites of prostate cancer metastases were targeted in 44 of 47 (93.6%) as determined by planar imaging. All experienced reversible hematologic toxicity, with grade 4 thrombocytopenia occurring in 46.8% (29.8% received platelet transfusions) without significant hemorrhage. A total of 25.5% experienced grade 4 neutropenia, with one episode of febrile neutropenia. The phase I maximum tolerated dose (70 mCi/m2) resulted in more 30% PSA declines (46.9% vs. 13.3%, P = 0.048) and longer survival (21.8 vs. 11.9 months, P = 0.03), but also more grade 4 hematologic toxicity and platelet transfusions. No serious nonhematologic toxicity occurred. Those with poor PSMA imaging were less likely to respond. Conclusion: A single dose of 177Lu-J591 was well tolerated with reversible myelosuppression. Accurate tumor targeting and PSA responses were seen with evidence of dose response. Imaging biomarkers seem promising. Clin Cancer Res; 19(18); 5182–91. ©2013 AACR.

Potential Impact of Postoperative Early Complications on the Timing of Adjuvant Chemotherapy in Patients Undergoing Radical Cystectomy: A High-Volume Tertiary Cancer Center Experience

BACKGROUND Perioperative cisplatin combination chemotherapy is associated with a survival benefit in patients with invasive bladder cancer (BCa). However, in a recent report from the National Cancer Database (NCDB), only 11.6% of stage III BCa patients received perioperative chemotherapy, the majority in the adjuvant setting. OBJECTIVE We explore the impact of postoperative complications on the timing of adjuvant chemotherapy. DESIGN, SETTING, AND PARTICIPANTS An independent review board approved the review of 1142 consecutive radical cystectomies (RC), and data from these cases were entered into a prospective complication database (1995-2005) which was utilized and retrospectively reviewed for accuracy at a single, academic, tertiary cancer center. INTERVENTIONS All patients underwent RC/urinary diversion by high-volume, fellowship-trained, urologic oncologists. MEASUREMENTS All complications within 90 d of surgery were defined and graded using a five-grade modification of the original Clavien system utilized at Memorial Sloan-Kettering Cancer Center and stratified into 11 categories. Grade 2-5 complications typically prohibit starting adjuvant chemotherapy. Univariate and multivariable logistic regression were used to evaluate variables associated with complications. RESULTS AND LIMITATIONS Overall, 64% (735 of 1142 patients) experienced one or more complications, of which 83% (611 of 735) were grade 2-5. Furthermore, 57% of grade 2-5 complications (347 of 611) occurred between discharge and 90 d, 38% (233 of 611) within 6 wk, and 19% (114 of 611) between 6 wk and 12 wk, the general time frame for adjuvant chemotherapy. Overall, 26% (298 of 1142 patients) required readmission. Surgical morbidity at a high-volume tertiary cancer center may not reflect the case mix or surgical experience seen in the community setting. CONCLUSION This series demonstrates that 30% of patients (347 of 1142) undergoing RC may not have been able to receive adjuvant chemotherapy due to postoperative complications. This information should be taken into consideration when planning multimodal therapy and further supports the use of perioperative chemotherapy in the neoadjuvant setting.

A role for neoadjuvant gemcitabine plus cisplatin in muscle-invasive urothelial carcinoma of the bladder: a retrospective experience.

Neoadjuvant cisplatin‐based chemotherapy improves survival in muscle‐invasive urothelial cancer, with MVAC (methotrexate, vinblastine, doxorubicin and cisplatin) considered the standard regimen. Gemcitabine plus cisplatin (GC) has similar efficacy and less toxicity than MVAC in metastatic disease, but is untested as neoadjuvant treatment.

Phase II Study of Sunitinib in Patients With Metastatic Urothelial Cancer

PURPOSE No standard therapy exists for metastatic urothelial cancer (UC) that has progressed after initial chemotherapy. This trial was designed to assess the efficacy and tolerability of sunitinib in patients with advanced, previously treated UC. PATIENTS AND METHODS In this phase II trial, 77 patients received sunitinib between September 2006 and January 2009 on one of two schedules (50 mg per day for 4 weeks on and 2 weeks off [cohort A], 37.5 mg per day continuously [cohort B]), using a Simon 2 stage design in each cohort separately. RESULTS A partial response was seen in three of 45 patients (95% CI, 1% to 18%) in cohort A, and in one of 32 patients (95% CI, 0% to 16%) in cohort B. Clinical regression or stable disease was achieved in 33 of 77 patients (43%). Tumor regression lasted between 0.6 and 23.4 months with 29% of patients achieving response lasting longer than 3 months. The progression-free survival (2.4 v 2.3 months; P = .4) and overall survival (7.1 v 6.0 months; P = .4) were similar in both cohorts. There was one treatment-related death, and 47 patients (33 cohort A, 24 cohort B) experienced grade 3 or 4 toxicity. CONCLUSION Sunitinib did not achieve the predetermined threshold of >or= 20% activity defined by Response Evaluation Criteria in Solid Tumors. However, antitumor responses were observed, identifying the vascular endothelial growth factor axis as a viable pathway for UC treatment. The reported clinical benefit in previously treated patients warrants further investigation in a disease for which there is no US Food and Drug Administration-approved treatment.