Molecular Correlative Studies Research Articles

A prospective phase 2 single-arm study to evaluate the efficacy and safety of neoadjuvant pembrolizumab plus chemotherapy in patients with locally advanced esophageal squamous cell carcinoma (Keypoint-1).

4088 Background: Esophageal squamous cell carcinoma (ESCC) is the most prevalent esophageal cancer type worldwide with poor prognosis and limited treatment options. Combination immunotherapy and chemotherapy improved the outcomes in patients (pts) with metastatic esophageal cancer. However, the benefit of neoadjuvant immuno-chemotherapy in pts with locally advanced ESCC is unknown. We evaluated the efficacy and safety of neoadjuvant treatment with pembrolizumab plus chemotherapy in pts with locally advanced ESCC. Methods: Eligible pts who were aged 18-80 years with untreated, locally advanced ESCC were enrolled in this single-arm, phase 2 trial at Peking Union Medical College Hospital (China) from July 2020 to April 2022. Pts received neoadjuvant treatment with docetaxel 75 mg/m2, carboplatin area under the curve (AUC) 4-5 (or cisplatin 75 mg/m2), and pembrolizumab 200 mg via IV every 3 weeks. Within 4-8 weeks of completion of neoadjuvant treatment, pts underwent surgery. The primary endpoint was pathological complete response (pCR) rate. The secondary endpoints were treatment-related adverse events and R0 resection rate. The study is registered at ClinicalTrials.gov (NCT05302011). Results: Thirty pts were enrolled (Table). As of December 1, 2023, median follow-up time was 27.9 months. Twenty-eight pts received 4 cycles and 2 received 3 cycles of the neoadjuvant treatment. Six pts did not proceed with surgery because of disease progression (3/6) and personal choice (3/6). Twenty-four pts (24/30, 80%) underwent minimally invasive esophagectomy (MIE). The R0 resection rate was 100%. Perioperative complications were manageable, including anastomotic leakage (2/24, 8.3%) and nerve injury (1/24, 4.2%). Of these 24 pts, 7 (29.2%) achieved pCR and 5 (20.8%) were CAP1 (near complete response, College of American Pathologists protocol). The median disease-free survival (DFS) was 30.6 months. Median overall survival data is not yet available. Grade 3/4 treatment-related adverse events include leukopenia (10, 33.3%), alopecia (3, 10.0%), and pneumonitis (1, 3.3%). One patient died of Stevens-Johnson syndrome. We are conducting molecular and immunological correlative studies to explore potential biomarkers related to the treatment. Conclusions: Neoadjuvant treatment with combination pembrolizumab and chemotherapy demonstrated encouraging anti-tumor activities, good surgical outcomes and a manageable safety profile in pts with locally advanced ESCC, supporting further evaluation in a prospective randomized phase 3 trial. Clinical trial information: NCT05302011 . [Table: see text]

A phase I dose-escalation clinical trial with PLZ4-coated paclitaxel-loaded micelles (PPM) in patients with recurrent or refractory non-myoinvasive bladder cancer.

TPS4615 Background: Bladder carcinoma is one of the top ten cancers in the US with approximately 75% of patients initially presenting with non-myoinvasive bladder cancer (NMIBC). The current standard of care for NMIBC is transurethral resection (TUR) followed by intravesical instillation, usually with Bacille Calmette-Guérin (BCG). Despite combination treatment, 20-80% of patients' disease recurs and 25% progress to invasive stages. The study drug, PLZ4-coated paclitaxel-loaded micelle (PPM), is a solvent-free injectable nanoscale micelle formulation of paclitaxel (PTX). Preclinical data on bladder cancer-specific targeting ligand named PLZ4 has shown potential to specifically deliver chemotherapeutic micelle into bladder cancer cells, both in vitro and in vivo (Zhang, Urol Oncol 2012). In a toxicokinetic study, female Sprague Dawley rats were given intravesicular injections of PPM once weekly for 6 consecutive weeks. No drug related mortality was reported, and no systematic exposure of PPM was observed in toxicokinetic analysis. The purpose of this phase I trial with PPM is to determine the toxicity and recommended Phase II dose. Methods: This is a single arm, open label, Phase I dose-escalation first-in-human trial with an expansion cohort for the treatment of recurrent or refractory NMIBC with PPM. Eligibility includes BCG unresponsive carcinoma in situ or Ta/T1 urothelial carcinoma. Treatment with pembrolizumab is not an inclusion or exclusion criteria as intravesical taxane has comparable efficacy as intravenous pembrolizumab. Up to 29 patients will be recruited at VA Boston Healthcare system. PPM will be given once weekly for six weeks, 50 ml of solution regardless of patient's size or weight will be administered as intravesical instillation. A 3 + 3 design is adopted for this Phase I trial. There are three dose levels at the dose escalation stage: Dose level I: PTX 25 mg or 0.5 mg/ml; Dose Level II: PTX 50 mg or 1.0 mg/ml; Dose Level III: PTX 75 mg or 1.5 mg/ml. At the expansion cohort, up to 12 patients will be treated with PPM at PTX dose of 50 mg or 1.0 mg/ml to determine the efficacy. The primary objective is to evaluate the safety and tolerability of PPM administered through intravesical instillation and determine the recommended Phase II dose of PPM. The secondary objectives are to evaluate the tumor response at 6 weeks after last treatment, determine systemic absorption within 6 hours after intravesical instillation of PPM and assess progression free survival. The efficacy will be determined by urine cytology and cystoscopy after finishing treatment. Molecular correlative studies will be performed. The toxicity will be assessed by Common Terminology Criteria for Adverse Events v5.0. Patients will be followed at 3 month intervals for 2 years or until disease recurrence or progression. This study is currently open for enrollment. NCT05519241. Clinical trial information: NCT05519241 .

A phase II trial with copanlisib plus avelumab as maintenance therapy for metastatic bladder cancer after platinum-based chemotherapy.

TPS4610 Background: Bladder cancer is the tenth most common malignancy and the fourteenth most common cause of cancer death worldwide. Currently, platinum-based chemotherapy followed by avelumab maintenance immunotherapy is the first-line standard of care for advanced bladder cancer (aBC). Even though maintenance avelumab therapy has improved overall survival, its efficacy is still disappointing with a response rate of less than 10% and progression-free survival benefit of 1.7 months. The phosphoinositide 3-kinase (PI3K) pathway harbors more activating alterations than any other growth signaling pathway in aBC. Furthermore, PI3K δ and γ are expressed by immune cells and regulate their function. Activation alterations along the PI3K pathway are putative molecular drivers and can possibly be targeted for the treatment of aBC. In preclinical studies, we found that a pan-PI3K class I inhibitor, copanlisib, potentiates anti-programmed cell death 1 (PD1) antibody in syngeneic bladder cancer mouse models with or without activation alterations along the PI3K pathway (Zhu S, J Immunother Cancer. 2021). We hypothesize that copanlisib potentiates avelumab as maintenance therapy for aBC. Methods: This is a multi-center, single-arm, open-label Phase II trial with a lead-in safety phase to determine the efficacy and toxicity of combination copanlisib and avelumab maintenance therapy in aBC. The major inclusion criteria are patients with aBC without disease progression after platinum-based chemotherapy and no contraindication for avelumab and copanlisib. With a type I error of 5% and power of 80% with a log-rank test, we will need 26 patients for this study. With an attrition rate of 10%, we will enroll 29 patients from four US Department of Veterans Affairs Medical Centers. Copanlisib will be administered through intravenous infusion (IV) at 60 mg on Day 1, 8 and 15, and avelumab will be administered 800 mg IV on Day 1 and 15 of each 4-week treatment cycle for up to 26 cycles. Imaging will be repeated every two cycles during first year of therapy and thereafter every 3 cycles or clinically indicated. The primary endpoint is progression-free survival (PFS). The secondary endpoints include CT or MRI determined radiographic overall response rate, toxicity, overall survival, and molecular correlative studies. Kaplan-Meier estimates will be presented together with median PFS with 2-sided 95% confidence intervals (CI). In particular, the PFS rates at 3, 6, 9, 12 and 15 months will be estimated with corresponding 2-sided 95% CIs. Adverse events will be assessed according to CTCAE v5. Tumor response is determined according to Response Evaluation Criteria in Solid Tumors version (RECIST) 1.1 criteria. This study is currently open for enrollment. Clinical trial information: NCT05687721 .

Phototherapy with Cancer-Specific Nanoporphyrin Potentiates Immunotherapy in Bladder Cancer.

Immune checkpoint inhibitors (ICI) in general have shown poor efficacy in bladder cancer. The purpose of this project was to determine whether photodynamic therapy (PDT) with bladder cancer-specific porphyrin-based PLZ4-nanoparticles (PNP) potentiated ICI. SV40 T/Ras double-transgenic mice bearing spontaneous bladder cancer and C57BL/6 mice carrying syngeneic bladder cancer models were used to determine the efficacy and conduct molecular correlative studies. PDT with PNP generated reactive oxygen species, and induced protein carbonylation and dendritic cell maturation. In SV40 T/Ras double-transgenic mice carrying spontaneous bladder cancer, the median survival was 33.7 days in the control, compared with 44.8 (P = 0.0123), 52.6 (P = 0.0054), and over 75 (P = 0.0001) days in the anti-programmed cell death-1 antibody (anti-PD-1), PNP PDT, and combination groups, respectively. At Day 75 when all mice in other groups died, only 1 in 7 mice in the combination group died. For the direct anti-tumor activity, compared with the control, the anti-PD-1, PNP PDT, and combination groups induced a 40.25% (P = 0.0003), 80.72% (P < 0.0001), and 93.03% (P < 0.0001) tumor reduction, respectively. For the abscopal anticancer immunity, the anti-PD-1, PNP PDT, and combination groups induced tumor reduction of 45.73% (P = 0.0001), 54.92% (P < 0.0001), and 75.96% (P < 0.0001), respectively. The combination treatment also diminished spontaneous and induced lung metastasis. Potential of immunotherapy by PNP PDT is multifactorial. In addition to its potential for photodynamic diagnosis and therapy, PNP PDT can synergize immunotherapy in treating locally advanced and metastatic bladder cancer. Clinical trials are warranted to determine the efficacy and toxicity of this combination.

Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer (ERIGE trial). Clinical and pharmacogenetic results on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC)

BackgroundThe combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, particularly in triple negative breast cancer (TNBC) characterized by high cell proliferation, aggressive behavior, and chemo-resistance.Patients and methodsThis is an open-label, multicenter phase II study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on days 1 and 8 of a 21-day cycle as either first- or second-line treatment of locally advanced or metastatic TNBC. The primary endpoint was the objective response for evaluable patients. A prospective, molecular correlative study was carried out to assess the role of germinal BRCA pathogenic variants and single nucleotide polymorphisms (SNPs) in predicting efficacy and toxicity of the combination regimen.ResultsFrom July 2013 to September 2016, 83 evaluable patients were enrolled. They received a median number of six cycles of treatment. An overall response rate (ORR) of 37.3% (31 patients) was observed, with a complete response rate of 2.4% and a partial response rate of 34.9%; the clinical benefit rate was 48.8%. With a median follow-up of 28.8 months, the median response duration was 6.6 months, the median progression-free survival (PFS) was 5.1 months, and the median overall survival (OS) was 14.5 months. The most common grade 3-4 adverse events were aminotransferase elevation (in 25% of the patients) and neutropenia (in 23.8%). Women with BRCA1/2 pathogenic variants were associated with worse ORR, PFS, and OS than BRCA1/2 wild-type carriers. CYP3A4 and FGD4 SNPs were associated with increased risk of liver toxicity. Three different SNPs in CDA∗2, RRM1, and CYP2C8 genes were significantly associated with poorer OS.ConclusionsThe combination of eribulin and gemcitabine showed promising activity and a moderate toxicity profile in metastatic TNBC. BRCA status and pharmacogenetics tests may help identify patients with high probability of response with negligible toxicity.EudraCT number2012-003505-10.

Definition, Biology, and History of Oligometastatic and Oligoprogressive Disease.

Historical theories of metastasis have been informed by the seed and soil hypothesis, the Halsteadian paradigm proposing an orderly spread from local to distant sites, and the presumption that cancer is an inherently systemic process even in the earliest cases. The more contemporary spectrum theory now suggests that the propensity for distant spread exists along a continuum of metastatic virulence. Tumors with limited metastatic potential represent one subset along this spectrum that could potentially be cured with local ablative therapy. Integrating clinical and molecular features to biologically inform the classification of not only oligometastatic or oligoprogressive disease but also the entire metastatic spectrum holds great promise to improve prognostication and inform clinical decision making. To this end, the inclusion of molecular correlative studies and biospecimen collection on prospective protocols is imperative.

Abstract P1-14-05: Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer (ERIGE Trial). Clinical and pharmacogenetic results on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC)

Abstract Background: There are no well-established chemotherapy regimens for metastatic triple negative breast cancer. The combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, especially in tumors like triple negative breast cancers (TNBC) characterized by high cell proliferation, aggressive tumor behavior, and chemo-resistance. Materials and Methods:This is an open-label, national multicenter phase II study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on day 1 and 8, q21 as either first- or second-line treatment of locally advanced or metastatic TNBC.The primary endpoint was the objective response rate (ORR) for evaluable patients (pts). The study was designed according to the Simon's two stage optimal design. We chose the lower activity (p0) of 0.20 and target activity level (p1) of 0.35. A prospective, molecular correlative study has been being carried out on germinal DNA of study population to assess the role of BRCA mutations and single nucleotide polymorphisms (SNPs) in predicting efficacy and toxicity of the combination regimen. Results: From July 2013 to September 2016, 83 evaluable pts (37 in the first stage, 46 in the second one) were enrolled. They received a median number of 6 cycles of treatment (range 1-24). The ORR (CR+PR) was 37.35% (90% CI: 28.47-46.93) and the clinical benefit rate (CR+PR+SD ≥ 24wks) was 48.78% (90% CI: 39.24%-58.39%). The most common grade 3-4 adverse events (&amp;gt; 10% of patients) were neutropenia and liver toxicity. With a median follow-up of 28.8 months, the median progression-free survival (PFS) and overall survival (OS) were 5.1 months (95% CI: 4.2-7.0) and 14.7 months (95% CI: 10.2-20.0), respectively. BRCA1/2 deleterious mutations were observed in 15 (22%) out of 68 genotyped pts. Women with BRCA1/2 mutations were associated with worse ORR, PFS and OS than those with BRCA1/2 wild-type. A panel of SNPs in genes of study drug metabolism pathways was evaluated. Among these, CYP3A4 392A &amp;gt;G and FGD4 2044236G&amp;gt;A SNPs were associated with greater liver toxicity by logistic regression analysis. Furthermore, CDA*2 79A&amp;gt;C, RRM1 2455 A&amp;gt;G, and CYP2C8 416G&amp;gt;A SNPs were associated with poorer overall survival by Cox proportional hazards model. Conclusions:The combination of eribulin and gemcitabine shows promising activity and a moderate toxicity profile in metastatic TNBC. BRCA status and pharmacogenetics tests may help identify pts with high probability of response with negligible toxicity. Citation Format: Musolino A, Cavanna L, Boggiani D, Zamagni C, Frassoldati A, Caldara A, Rocca A, Gori S, Piacentini F, Berardi R, Brandes AA, Foglietta J, Villa F, Pellegrino B, Todeschini R, Tognetto M, Naldi N, Bortesi B, Boni L, Montemurro F, Ardizzoni A. Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer (ERIGE Trial). Clinical and pharmacogenetic results on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-14-05.

Oligometastatic prostate cancer: Reality or figment of imagination?

The term “oligometastatic prostate cancer” refers to a heterogeneous group of disease states currently defined solely on the basis of clinical features. Oligorecurrent disease, de novo oligometastases, and oligoprogressive disease likely have unique biologic underpinnings and natural histories. Evidence suggesting the existence of a subset of patients who harbor prostate cancer with limited metastatic potential currently includes disparate and overwhelmingly retrospective reports. Nevertheless, emerging prospective data have corroborated the “better‐than‐expected,” retrospectively observed outcomes, particularly in the setting of oligorecurrent prostate cancer. Improved functional imaging with prostate‐specific membrane antigen‐targeted strategies may enhance the identification of patients with oligometastatic prostate cancer in the short term. In the long term, refinement of the oligometastatic case definition likely will require biologic risk‐stratification schemes. To determine optimal treatment strategies and identify patients most likely to benefit from metastasis‐directed therapy, future efforts should focus on conducting high‐quality, prospective trials with much‐needed molecular correlative studies.

Niclosamide in combination with abiraterone and prednisone in men with castration-resistant prostate cancer (CRPC): initial results from a phase Ib/II trial.

192 Background: Prostate cancer is driven by androgen receptor (AR) signaling. The variant AR-V7 lacks the ligand binding domain, constitutively activates the AR pathway, and confers resistance to Abiraterone (Abi) and enzalutamide (Enza). We discovered that the anti-helminthic drug niclosamide targets AR-V7 and sensitizes resistant CRPC to Enza and Abi. We hypothesize that niclosamide/PDMX1001 potentiates the efficacy of Abi against CRPC. Here we report the initial results of this ongoing investigator-initiated phase Ib/II trial. Methods: Eligible patients (pts) have progressive CRPC with serum testosterone &lt; 50 ng/dl. No prior Abi was allowed. In the Phase Ib cohort, pts received Abi 1000 mg PO qd, prednisone 5 mg PO bid, with intrapatient dose-escalation of niclosamide/PDMX1001 from 400 mg PO bid to 1600 mg PO tid. Trough niclosamide/PDMX1001 levels were measured. The Phase II cohort will enroll 27 patients with detectable AR-V7 in the peripheral blood. Co-primary endpoints include toxicity and response as determined by the Prostate Cancer Working Group 2 criteria. Results: Of 6 pts (age 74-83) in the Phase Ib cohort, five pts tolerated a niclosamide/PDMX1001 dose of 1,600 mg po tid without dose limiting toxicity; per protocol, this is the recommended Phase II dose. Niclosamide/PDMX1001 trough level was 0.305 and 0.496 µM in the two pts analyzed thus far, higher than the target level of 0.1µM required for anti-cancer activity. Of 6 pts, two pts achieved complete PSA response ( &lt; 0.01 ng/ml), compared to historical control 0/30 pts treated with Abi alone; two with partial PSA response (≥50% decrease). Of the remaining two pts, one was prematurely taken off from the study after one cycle because of rising PSA, and the other had PSA decrease of 17.1%, but biopsy of the only enlarged lymph node showed all necrotic tissue. The only toxicity was Grade 1 nausea and diarrhea. The Phase II cohort will now enroll. Molecular correlative studies will be presented. Conclusions: The combination of niclosamide/PDMX1001, Abi and prednisone is well tolerated with promising safety and efficacy data. Targeted serum trough levels of niclosamide are clinically achievable. Clinical trial information: NCT02807805.

A phase Ib/II trial of indomethacin and enzalutamide to treat castration-resistant prostate cancer (CRPC).

TPS394 Background: Enzalutamide (Enza) and abiraterone (Abi) are commonly used to treat CRPC. Resistance is the most common cause of treatment failure. We discovered that a critical steroidogenic enzyme AKR1C3 was significantly elevated and contributed to intratumoral androgen synthesis in Enza-resistant prostate cancer cells and tumors. Overexpression of AKR1C3 induced androgen receptor variant 7 (AR-V7) expression, while inhibition of AKR1C3 downregulated AR-V7. We then discovered that indomethacin (Indo) inhibited AKR1C3 activation and sensitized resistant CRPC cells to Enza and Abi. One patient accidentally took Indo and achieved biochemical as well as radiological response of his prostate cancer. These findings prompted us to design a clinical trial to test the combination of Indo with Enza for the treatment of CRPC and to study the underlying mechanisms of action and resistance. Methods: This investigator-initiated single-arm Phase Ib/II trial enrolls patients with progressive CRPC after Abi, adequate vital organ function, ECOG performance status 0-2, and serum testosterone &lt; 50 ng/dl. Major exclusion criteria include prior Enza treatment, brain metastasis and history of seizure. In the Phase Ib cohort, patients receive Enza 160 mg po qd and Indo 50 mg po tid to determine toxicity. The Phase II expansion will enroll 26 patients with 21 evaluable patients. This sample size provides 90% power to detect, at the 0.05 level (1-sided), the difference between a PSA response rate of 50% expected with the study treatment and a historical control of 20% with Enza alone. Co-primary endpoints are safety and PSA response of ≥50% decrease. Secondary endpoints include overall response rate as determined by the Prostate Cancer Working Group 2 criteria (PCWG2), progression-free survival and overall survival. Molecular correlative studies are exploratory endpoints. Serum and intratumoral androgen levels, full-length AR, AR-V7 and AKR1C3 will be measured to assess the effect of the combination therapy. To date, 4 patients have been enrolled to the trial (clinicaltrials.gov Identifier No: NCT02935205; this trial is funded by DoD Prostate Cancer Research Program IMPACT award). Clinical trial information: NCT02935205.

Abstract CT083: Clinical activity, immune and molecular correlates of nivolumab vs. nivolumab plus bevacizumab vs nivolumab plus ipilimumab in metastatic renal cell carcinoma

Abstract Background: Immune checkpoint blockade including anti-CTLA-4 (ipilimumab, BMS) and anti-PD1 (nivolumab, BMS) as monotherapies have been known to have clinical activity against metastatic renal cell carcinoma (MRCC), but with relatively low clinical response rate (10-25%). Anti-VEGF antibody bevacizumab is a standard therapy for MRCC also with a low response rate (&amp;lt;20%). Since anti-PD1 and anti-CTLA-4 use distinct mechanisms for T cell activation and bevacizumab can promote the function of antigen presenting cells, we hypothesize that combination therapy with nivolumab + bevacizumab or nivolumab + ipilimumab will lead to measurable immunological changes and improved clinical activity. Methods: In this open-label, pilot, pre-surgical/pre-biopsy trial (NCT02210117), adults with MRCC without prior immune checkpoint therapy and anti-VGEF therapy were enrolled, stratified by planned surgical procedure, and randomized 1:2:1 to receive nivolumab monotherapy, nivolumab + bevacizumab or nivolumab + ipilimumab, followed by cytoreductive nephrectomy, metastasectomy, or post-treatment biopsy, and subsequent maintenance therapy with nivolumab for up to 2 years until disease progression and intolerable toxicity. Pre- and post-treatment blood and tumor samples were obtained for dynamic monitoring of immune and molecular correlates to clinical activity. Results: Sixty patients were treated (median duration 17.1 weeks, range 2.74 to 85.1 weeks as of 12/6/16). Fourty-four were evaluable for clinical responses post-procedures. Five of 12 (42%) nivolumab monotherapy treated patients had partial response (PR), 4 (33%) had stable disease (SD), and 3 (25%) had progression of disease (PD) and 0 withdrew early (W). In the nivolumab + bevacizumab arm, 1 of 19 (5%) had complete response and 9 (47%) patients had PR, for a response rate of 53%, 3 (16%) had SD, 3 (16%) with PD and 3 (16%) W. In the nivolumab + ipilimumab arm, 5 of 13 (38%) patients had PR, 1 (8%) had SD and 5 (38%) had PD and 2 (15%) W. Treatment was generally well tolerated with mostly grade 1 or 2 adverse events. Grade 3 or higher toxicities were 19% in the nivolumab arm, 41% in the nivolumab + bevacizumab arm (including 17% bevacizumab-specific hypertension that was well controlled by anti-hypertensive medications), and 27% in the nivolumab + ipilimumab arm. Correlative laboratory studies including flow cytometry, IHC, and gene profiling analysis identified a number of immune gene signatures including an IFN-γ gene signature that we will report in more details. Conclusions: Combination therapy with nivolumab + bevacizumab and nivolumab + ipilimumab showed promising clinical activities in patients with MRCC. Immune and molecular correlative studies may allow us to identify novel biomarkers that can be used for correlation with clinical outcomes in patients with MRCC. Citation Format: Jianjun Gao, Jose A. Karam, Christopher G. Wood, Surena Matin, Kamran Ahrar, Eric Jonasch, Nizar Tannir, Matthew Campell, Chaan S. Ng, Rebecca S. Slack, Priya Rao, James P. Allison, Jorge M. Blando, Luis M. Vence, Sreyashi Basu, Hao Zhao, Tenghui Chen, Hong Chen, Padmanee Sharma. Clinical activity, immune and molecular correlates of nivolumab vs. nivolumab plus bevacizumab vs nivolumab plus ipilimumab in metastatic renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT083. doi:10.1158/1538-7445.AM2017-CT083

Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer: ERIGE trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC).

1095 Background: There are no well-established chemotherapy regimens for metastatic triple negative breast cancer. The combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, especially in tumors like triple negative breast cancers (TNBC) characterized by high cell proliferation, aggressive tumor behavior, and chemo-resistance. Methods: We performed an open-label, national multicenter phase 2 study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on day 1 and 8, q21 as either first- or second-line treatment of locally advanced or metastatic TNBC. The Simon's optimal two-stage design was used for estimating objective response rate (ORR) as study primary endpoint. A prospective, molecular correlative study was carried out on germinal DNA of study population to assess the role of germinal DNA polymorphisms and BRCA mutations in predicting efficacy and toxicity of the combination regimen. Results: From July 2013 to September 2016 , 83 (37 in the first stage, 46 in the second one) assessable patients were enrolled. Median age at baseline was 56 years. Sixty-six and 17 patients were in first or second-line treatment, respectively. All patients were previously treated with an anthracycline and/or a taxane. With regard to the first stage of study enrolment, patients received a median number of 6 cycles of treatment. The ORR (CR+PR) was 43.24% (90% CI 29.3-58.0) and the clinical benefit rate (CR+PR+SD) was 64.9% (90% CI: 50.1%-77.8%). The most common grade 3/4 AEs ( &gt; 10% of patients) were neutropenia without febrile neutropenia and liver toxicity. Grade 1/2 AEs were fatigue, anemia, thrombocytopenia, diarrhea, alopecia, peripheral neuropathy, and oral mucositis. Conclusions: The combination of eribulin and gemcitabine shows promising activity and a moderate toxicity profile in metastatic TNBC. More mature toxicity and outcome data of the final study population and correlation with genome analysis will be presented at the meeting. Clinical trial information: 2012-003505-10.

MP57-19 TARGETING AKR1C3 ACTIVATION BY INDOMETHACIN OVERCOMES RESISTANCE TO ENZALUTAMIDE AND ABIRATERONE

You have accessJournal of UrologyProstate Cancer: Advanced (including Drug Therapy) IV1 Apr 2017MP57-19 TARGETING AKR1C3 ACTIVATION BY INDOMETHACIN OVERCOMES RESISTANCE TO ENZALUTAMIDE AND ABIRATERONE Chengfei Liu, Wei Lou, Joy Yang, Chong-Xian Pan, Marc Dall'Era, Christopher Evans, and Allen Gao Chengfei LiuChengfei Liu More articles by this author , Wei LouWei Lou More articles by this author , Joy YangJoy Yang More articles by this author , Chong-Xian PanChong-Xian Pan More articles by this author , Marc Dall'EraMarc Dall'Era More articles by this author , Christopher EvansChristopher Evans More articles by this author , and Allen GaoAllen Gao More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.1793AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Resistance of prostate cancer (CaP) cells to enzalutamide and abiraterone, may be mediated by a multitude of survival signaling pathways. In this study we tested whether AKR1C3 activation and intracrine androgens induce CaP cell resistance to enzalutamide and abiraterone and whether targeting these resistance mechanisms overcomes resistance to enzalutamide and abiraterone and thus improve therapy. METHODS Global gene expression analysis was analyzed by microarray and transcriptome was analyzed by RNA-seq. Steroid profile including androgens was analyzed by Liquid Chromatography-Mass Spectrometry (LC-MS). The effects of AKR1C3 expression and activation were examined by knock down of AKR1C3 expression by shRNA or inhibition of AKR1C3 enzymatic activity by indomethacin. The effects of AKR1C3 activation on enzalutamide and abiraterone sensitivity were examined in vitro and in vivo. A Phase I/II clinical trial with enzalutamide plus indomethacin has been designed. RESULTS Global gene expression analysis showed that steroid biosynthesis pathway is activated in enzalutamide and abiraterone resistant prostate cancer cells. One of the crucial steroidogenic enzymes, AKR1C3, was significantly elevated in enzalutamide/abiraterone resistant cells. In addition, AKR1C3 is highly expressed in metastatic and recurrent prostate cancer and in enzalutamide resistant prostate xenograft tumors. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis of the steroid metabolites revealed that androgen precursors such as cholesterol, DHEA and progesterone, as well as androgens are highly up regulated in enzalutamide/abiraterone resistant prostate cancer cells compared to the parental cells. Knock down of AKR1C3 expression by shRNA or inhibition of AKR1C3 enzymatic activity by indomethacin resensitized enzalutamide/abiraterone resistant prostate cancer cells to enzalutamide/abiraterone treatment both in vitro and in vivo. In contrast, overexpression of AKR1C3 confers resistance to enzalutamide and abiraterone. Furthermore, the combination of indomethacin and enzalutamide/abiraterone resulted in significant inhibition of enzalutamide and abiraterone-resistant tumor growth. These results suggest that AKR1C3 activation is a critical resistance mechanism associated with enzalutamide/abiraterone resistance. In a Phase I/II combination of indomethacin with enzalutamide trial funded by Department of Defense, patients with mCRPC, good performance status (ECOG 0-2) and vital organ function, and no history of enzalutamide or indomethacin treatment will be recruited. The co-primary objective is to assess the toxicity and prostate-specific antigen (PSA) response (=50% reduction). We will also assess the overall response as determined by the Prostate Cancer Working Group 2 criteria, progression-free survival and molecular correlative studies. CONCLUSIONS AKR1C3 activation and resulting in an increase in intracrine androgens are critical resistance mechanisms confer resistance to enzalutamide and abiraterone. Targeting AKR1C3 activation may provide a potential treatment strategy for metastatic prostate cancer patients who develop resistance to enzalutamide and abiraterone. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e771 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Chengfei Liu More articles by this author Wei Lou More articles by this author Joy Yang More articles by this author Chong-Xian Pan More articles by this author Marc Dall'Era More articles by this author Christopher Evans More articles by this author Allen Gao More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Indomethacin to inhibit AKR1C3 intracrine androgen production and sensitizes prostate cancer (PCa) to enzalutamide.

161 Background: Enzalutamide (Enza) improves the treatment of metastatic castration-resistant PCa (mCRPC). Acquired resistance is the most common cause of treatment failure. Our objective was to determine mechanisms of resistance to Enza and develop novel therapy to overcome resistance. Methods: Enza-resistant PCa cells were established through continuous culture of C4-2B cells with Enza. Global gene expression array and western blots were used to assess gene expression in cell lines and validated in clinical specimens using Oncomine and GEO databases. The therapeutic effects of indomethacin were determined in cell culture and in mice carrying CWR22Rv1 xenografts. A Phase I/II clinical trial with Enza plus indomethacin has been approved by IRB. Results: Steroid biosynthesis pathways, especially AKR1C3, were significantly elevated in Enza resistant cells and was associated with high production of androgens. AKR1C3 was also highly expressed in metastatic and recurrent CaP and in Enza-resistant xenograft tumors. Overexpression of AKR1C3 conferred resistance to Enza. Inhibition of AKR1C3 expression by its specific shRNAs or AKR1C3 enzymatic activity by indomethacin re-sensitized Enza-resistant CaP cells to Enza treatment both in vitro and in vivo. Combination of indomethacin and Enza resulted in significant inhibition of Enza-resistant tumor growth. Indomethacin treatment in one patient with mCRPC induced tumor shrinkage and PSA decrease. In a Phase I/II trial funded by the Department of Defense, patients with mCRPC, good performance status (ECOG 0-2) and vital organ function, and no history of Enza or indomethacin treatment will be recruited. The co-primary objective is to assess the toxicity and prostate-specific antigen (PSA) response ( ≥ 50% reduction). We will also assess the overall response as determined by the Prostate Cancer Working Group 2 criteria, progression-free survival and molecular correlative studies. Conclusions: AKR1C3 activation is a critical resistance mechanism associated with Enza resistance. Indomethacin targets AKR1C3 and intratumor androgen synthesis, and can be potentially used as a therapeutic agent for mCRPC. Clinical trial results will be presented. Clinical trial information: to be registered.

Combination of Selinexor with High-Dose Cytarabine (HiDAC) and Mitoxantrone (Mito) for Remission Induction in Acute Myeloid Leukemia (AML) Is Feasible and Tolerable

Background: Selinexor, an exportin 1 (XPO1) inhibitor, has demonstrated anti-leukemic effect as a single agent. There are also data demonstrating synergistic killing of leukemia cells with the combination of selinexor with anthracyclines and/or DNA damaging agents. The HiDAC/Mito combination is an effective induction regimen for relapsed/refractory (R/R) AML patients with a reported overall response rate (ORR) of 55% at our institution. We hypothesize that adding selinexor to HiDAC/Mito is feasible and has synergistic anti-leukemic effects.Methods: We performed a phase I dose escalation trial with cohort expansion in patients with AML that combined increasing doses of selinexor with age-adjusted HiDAC/Mito (NCT02573363). The primary endpoint was to determine the maximum tolerated dose of selinexor when given in combination with HiDAC/Mito. Selinexor was given orally on days 2, 4, 9, and 11 during the induction phase of the study. HiDAC (1.5 to 3 gm/m2 depending on age, IV over 3 hours) followed immediately by Mito (20 to 30 mg/m2 IV over 1 hour) was administered on day 1 and 5. Initial selinexor dose was 60mg (~35mg/m2) followed by a dose escalation to a target level of 80mg (~50mg/m2). Patients who entered remission proceeded to stem cell transplantation (SCT) or consolidation chemotherapy with HiDAC/selinexor followed by maintenance therapy with weekly selinexor alone for up to one year. Dose limiting toxicity (DLT) was defined as any grade 3 or greater non-hematologic toxicity, except transient (<48 hours) nausea/vomiting or liver function abnormalities, or by persistent bone marrow aplasia lasting >56 days in the absence of disease. Once a dose level was declared tolerable, more patients could be enrolled at that level to provide additional safety, tolerability, and efficacy data.Results: As of July 2016, 12 patients had enrolled. Selinexor dose levels were 60mg (n=3) and 80mg (n=9). Median age = 61 (range 44 - 74). De novo AML = 5 (42%); secondary AML = 3 (25%), R/R AML = 4 (33%). Eight (67%) patients were previously untreated, 1 (8%) was beyond the first relapse, and 3 (25%) had primary refractory disease. Prior therapies included combination cytarabine with anthracycline, HiDAC, decitabine, and clinical trial agents. Molecular/genetic subgroup profiles by European Leukemia Net (ELN) criteria included favorable = 1 (8%), intermediate I = 5 (42%), intermediate II = 1 (8%), and adverse = 5 (42%).Only 10 patients are evaluable for safety and efficacy at the time of analysis. Myelosuppression was the most common side effect and was universal. Median and average times to count recovery for responding patients from day 1 were 38 and 47 days, respectively. Febrile neutropenia was observed in 8 patients (80%), compared to our historical experience of 64% for HiDAC/Mito alone. Other significant adverse events included line-associated thromboses (n=3), cardiac toxicity (n=3), cerebellar toxicity (n=1), arm cellulitis (n=1), and syncope (n=1). No DLTs were observed. 30 and 60-day induction mortality was 10% (1 patient with R/R AML died from progressive disease).Ten patients are evaluable for response: complete remission (CR) = 4 (40%), CR with incomplete count recovery (CRi) = 1 (10%), partial remission (PR) = 1 (10%), and treatment failure (TF) = 4 (40%). Thus, the ORR is 60%. Of those who responded, 2 patients proceeded to consolidation, 1 underwent allo-SCT, and 3 are in preparation for allo-SCT. No response was achieved in patients with R/R AML.Bone marrow samples from screening and day 12 of treatment were used for biomarker analysis in three CR patients. A marked reduction in KI67, MYC, FLT3, KIT, and DNA damage response proteins was observed in the remaining tumor cells in the post-treatment samples. Staining for P53 showed an increase in nuclear staining intensity, which is consistent with the known effect of selinexor on tumor cells.Conclusions: The selinexor/HiDAC/Mito regimen is feasible and tolerable at selinexor doses up to 80mg/day or ~50 mg/m2/day twice weekly. It yields an ORR of 60% based on currently available data. The recommended phase II dose is 80mg of selinexor. Additional molecular correlative studies are evaluating patients' marrow and blood samples for markers that predict response and relapse. DisclosuresOdenike:Spectrum Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Geron: Research Funding; Incyte: Honoraria, Membership on an entity’s Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Algeta Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Suneisis Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Stock:Sigma-Tau: Honoraria, Research Funding; ADC Therapeutics: Honoraria; Gilead Sciences: Honoraria; Amgen: Honoraria; Royalties for a chapter in Up to Date: Patents & Royalties. Liu:Karyopharm: Research Funding; BMS: Research Funding.

Abstract OT3-02-05: Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer. ERIGE Trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC)

Abstract Background: There are no well-established chemotherapy regimens for metastatic triple negative breast cancer. The combination of a microtubule inhibitor (eribulin) with a nucleoside analog (gemcitabine) may synergistically induce tumor cell death, especially in tumors like triple negative breast cancers characterized by high cell proliferation, aggressive tumor behavior, and chemo-resistance. Trial design: This is an open-label, national multicenter phase 2 study evaluating the combination of eribulin (0.88 mg/m2) plus gemcitabine (1000 mg/m2) on day 1 and 8, q21 as either first- or second-line treatment of locally advanced or metastatic triple negative breast cancer (TNBC). A prospective, molecular correlative study is being carried out on germinal DNA of study population. Eligibility criteria: Patients must have locally advanced or metastatic breast cancer with estrogen receptor-negative (ER &amp;lt; 1%), progesterone receptor-negative (PR &amp;lt; 1%), and human epidermal growth factor receptor 2-negative (Her2-) (0, 1+) or, e.g. in HER2 2+ cases, fluorescent in situ hybridization (FISH) &amp;lt; ratio of 1.8, status. Previous chemotherapy including an anthracycline and a taxane (unless one or both were clinically contraindicated) is mandatory. Up to one prior chemotherapy regimen for metastatic disease is permitted, with the exception of treatment with eribulin and gemcitabine. Patients must have: Measurable disease; Eastern Cooperative Oncology Group (ECOG) performance status 0-2; adequate bone marrow reserve, liver and renal function. Specific aims: The main objective of this trial is to evaluate the activity of eribulin plus gemcitabine in terms of overall response rate (ORR; RECIST 1.1). Secondary end-points are: Feasibiliy, safety (CTC-AE V4.0), progression-free and overall survival. The molecular correlative study aim is to assess the role of germinal DNA polymorphisms and BRCA mutations in predicting efficacy and toxicity with the combination regimen. Statistical methods: The primary endpoint is the ORR. The study is being carried out according to Optimal Simon's two stage design. We chose the lower activity (p0) of 0.20 and target activity level (p1) of 0.35. A total of 83 (37 in the first stage, 46 in the second one) assessable patients will be needed to guarantee 90% power under a α-level of 5%. Genotypic correlations with clinical responses and toxicities will be performed using a two-tailed Fisher's exact test. A logistic regression analysis including patients' genotypes will be used to identify independent prognostic variables influencing both clinical responses and toxicities. Present accrual and target accrual: A total of 83 eligible patients will be enrolled from multiple institutions. To date (June 09, 2015), the first stage has been closed with 37 patients enrolled. The second stage is now recruiting 46 additional patients. Citation Format: Musolino A, Caldara A, Montemurro F, Frassoldati A, Cavazzini G, Cavanna L, Todeschini R, Camisa R, Tognetto M, Pinto C. Phase II study of eribulin in combination with gemcitabine for the treatment of patients with locally advanced or metastatic triple negative breast cancer. ERIGE Trial on behalf of the Gruppo Oncologico Italiano di Ricerca Clinica (GOIRC). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-02-05.

Everolimus plus bicalutamide for castration resistant prostate cancer (CRPC): Bench to bedside and back.

189 Background: We previously reported that the mammalian target of rapamycin (mTOR) pathway was upregulated in CRPC, and that simultaneous blockade of both androgen receptor (AR) and mTOR pathways synergized in killing CRPC cells. Methods: Eligible patients (pts) must have progressive CRPC with serum testosterone &lt;50 ng/dl. No prior bicalutamide (except to prevent flare) or everolimus was allowed. Treatment regimen included daily bicalutamide 50 mg and everolimus 10 mg orally. Primary endpoint was prostate specific antigen (PSA) response (defined as ≥30% reduction). Sample size of 23 pts would have the power of 0.8 and alpha error of 0.05 (one-sided) if the combination had a PSA response rate of 50% vs. a historical rate of 25% with bicalutamide alone. Molecular correlative studies including serum ERBB3 levels were performed by ELISA. LNCaP and C4-2 cells, modeling bicalutamide-sensitivity and resistance, respectively, were transfected with ErbB3 or an empty vector and subjected to western blotting. Results: Of 24 pts enrolled, the mean number of treatment cycles was 7.9 (1.0-23.0). Eighteen pts had a PSA response (75%, 95% CI: 0.53-0.90). Median overall survival was 28 months (95% CI 14.1-42.7). Fourteen pts (54%, 95% CI 0.37, 0.78) developed Grade 3 (13 pts) or Grade 4 (1 pt with sepsis) adverse events attributed to study treatment. Pts with partial response showed a greater decline in ErbB3 (P=0.037) compared to those with stable disease or disease progression. Consistent with these findings, everolimus induced a decline in ErbB3 in hormone-sensitive LNCaP cells but failed to affect ErbB3 in CRPC C4-2 cells, which expressed 8-fold higher levels of ErbB3. Increased expression of ErbB3 in LNCaP cells resulted in resistance to everolimus, whereas bicalutamide initially prevented this effect. Prolonged exposure to bicalutamide also resulted in an increase in ErbB3 which correlated with increased growth rates and cell invasion. Conclusions: The combination of bicalutamide and everolimus has very encouraging efficacy in men with bicalutamide-naïve CRPC, but with substantial everolimus-related toxicity. ERBB3 may contribute to resistance and deserves further study. Clinical trial information: NCT00814788.

Overcoming VEGF resistance in renal cancer: biologic and therapeutic implications

Over the last few years, significant progress in the management of metastatic renal cell carcinoma (RCC) has been made. Although currently US FDA-approved therapies have shown dramatic efficacy, none of these have led to complete and durable responses. In addition to their complex side-effect profile, all patients eventually developed progressive disease and ultimately succumbed to their disease. Multiple clinical trials have addressed the importance of sequential therapy in RCC; however, none of them have built molecular correlative studies that would allow us to define the process of resistant disease. Emerging preclinical data demonstrate that VEGF remains an important driver in the resistance setting. Newer pathways such as the Tie2/ANG-2 pathway also appear to contribute to the resistant process. Future clinical trials will incorporate some of these concepts with the goal of providing a more rational selection of sequential therapies in metastatic RCC.

Examining the effects of metformin on survival outcome in stage II/III colorectal cancer patients with diabetes mellitus.

3589 Background: Insulin resistance and deregulation of the insulin-like growth factor (IGF) axis is implicated in colonic carcinogenesis. Metformin inhibits hepatic gluconeogenesis and increases insulin sensitivity. It induces AMPK activation, thus inhibiting mTOR and downstream survival and proliferation pathways. We evaluated the effects of metformin on survival outcomes of patients with stage 2 and 3 colorectal cancer (CRC). Methods: Among 1455 patients with stage II or III colorectal cancer, we identified 344 patients with both CRC and diabetes mellitus. 219 diabetic patients received metformin and 125 diabetic patients were not receiving metformin. Patient’s demographics, clinical and histopathologic characteristics, overall survival, time to recurrence and relapse-free survival were evaluated. Molecular analysis for AMPK, and mTOR pathway on archival tissue is ongoing. Results: After a median follow-up of 78 months (6.5 years), there was no difference in survival outcomes between diabetic and non-diabetic patients. Among diabetic patients, there were 99 relapses and 90 deaths. Metformin use was associated with improved overall survival (HR 0.23; 95%CI: 0.15-0.35 p&lt;0.01), time to recurrence (HR 0.63; 95%CI: 0.41-0.96) and relapse-free survival (HR 0.47; 95%CI:0.33-0.67,p&lt;0.01). In multivariate analysis, after adjustment for T stage, N stage and patients' age, metformin use remained associated with improved overall survival (HR 0.18, p&lt;0.01); time to recurrence (HR 0.55; p&lt;0.04) and relapse-free survival (HR 0.44, p&lt;0.01). Results of molecular correlative studies performed on archival tissue will be presented at the meeting. Conclusions: Among patients with diabetes and colorectal cancer, use of metformin is associated with improved survival outcomes in both univariate and multivariate analysis lending support to the hypothesis that it may have anti-cancer activity.

Early Tumor Progression Associated with Enhanced EGFR Signaling with Bortezomib, Cetuximab, and Radiotherapy for Head and Neck Cancer

A phase I clinical trial and molecular correlative studies were conducted to evaluate preclinical evidence for combinatorial activity of the proteasome inhibitor bortezomib, the epidermal growth factor receptor (EGFR) inhibitor cetuximab, and radiation therapy. Patients with radiotherapy-naive stage IV or recurrent squamous cell carcinoma of the head and neck (SCCHN) were studied. Escalating doses of bortezomib (0.7, 1.0, and 1.3 mg/m²) were given intravenously twice weekly on days 1, 4, 8, and 11, every 21 days, with weekly cetuximab beginning 1 week prior and concurrently with intensity-modulated radiotherapy, delivered in 2 Gy fractions to 70 to 74 Gy. Molecular effects were examined in serial serum and SCCHN tumor specimens and the cell line UMSCC-1. Seven patients were accrued before the study was terminated when five of six previously untreated patients with favorable prognosis oropharyngeal SCCHN progressed within 1 year (progression-free survival = 4.8 months; 95% CI, 2.6-6.9). Three patients each received bortezomib 0.7 or 1.0 mg/m², without dose-limiting toxicities; one patient treated at 1.3 mg/m² was taken off study due to recurring cetuximab infusion reaction and progressive disease (PD). Expected grade 3 toxicities included radiation mucositis (n = 4), dermatitis (n = 4), and rash (n = 1). SCCHN-related cytokines increased in serial serum specimens of patients developing PD (P = 0.029). Bortezomib antagonized cetuximab- and radiation-induced cytotoxicity, degradation of EGFR, and enhanced prosurvival signal pathway activation in SCCHN tumor biopsies and UMSCC-1. Combining bortezomib with cetuximab and radiation therapy showed unexpected early progression, evidence for EGFR stabilization, increased prosurvival signaling, and SCCHN cytokine expression, warranting avoidance of this combination.