A shared neoantigen vaccine combined with immune checkpoint blockade for advanced metastatic solid tumors: phase 1 trial interim results

Therapeutic vaccines that elicit cytotoxic T cell responses targeting tumor-specific neoantigens hold promise for providing long-term clinical benefit to patients with cancer. Here we evaluated safety and tolerability of a therapeutic vaccine encoding 20 shared neoantigens derived from selected common oncogenic driver mutations as primary endpoints in an ongoing phase 1/2 study in patients with advanced/metastatic solid tumors. Secondary endpoints included immunogenicity, overall response rate, progression-free survival and overall survival. Eligible patients were selected if their tumors expressed one of the human leukocyte antigen-matched tumor mutations included in the vaccine, with the majority of patients (18/19) harboring a mutation in KRAS. The vaccine regimen, consisting of a chimp adenovirus (ChAd68) and self-amplifying mRNA (samRNA) in combination with the immune checkpoint inhibitors ipilimumab and nivolumab, was shown to be well tolerated, with observed treatment-related adverse events consistent with acute inflammation expected with viral vector-based vaccines and immune checkpoint blockade, the majority grade 1/2. Two patients experienced grade 3/4 serious treatment-related adverse events that were also dose-limiting toxicities. The overall response rate was 0%, and median progression-free survival and overall survival were 1.9 months and 7.9 months, respectively. T cell responses were biased toward human leukocyte antigen-matched TP53 neoantigens encoded in the vaccine relative to KRAS neoantigens expressed by the patients' tumors, indicating a previously unknown hierarchy of neoantigen immunodominance that may impact the therapeutic efficacy of multiepitope shared neoantigen vaccines. These data led to the development of an optimized vaccine exclusively targeting KRAS-derived neoantigens that is being evaluated in a subset of patients in phase 2 of the clinical study. ClinicalTrials.gov registration: NCT03953235 .

Selective internal radiation therapy using yttrium-90 microspheres for treatment of localized and locally advanced intrahepatic cholangiocarcinoma

OBJECTIVES

To evaluate safety and effectiveness of selective internal radiation therapy (SIRT) using yttrium-90 for localized and locally advanced intrahepatic cholangiocarcinoma (iCCA).

METHODS

A retrospective review was performed of patients with localized iCCA treated with SIRT at a single institution. Overall survival (OS), local tumor response, progression-free survival (PFS), and toxicity were collected. Stratified analysis was performed based on surgical resection. Predictor analysis of OS was performed using the Fine-Grey regression analysis model with patients bridged to surgery regarded as competing events.

RESULTS

A total of 28 consecutive patients with localized iCCA were treated with a total of 38 sessions of SIRT (17 segmental, 13 lobar, and 8 combined deliveries) and a mean dominant target dose per session of 238.4 ± 130.0 Gy. The cumulative radiologic response rate was 16/28 (57.1%) with a median PFS of 265 days. Median survival time (MST) was 22.9 months for the entire cohort with 1-year and 3-year survival of 78.4% and 45.1%, respectively. Ten patients (34.5%) were downstaged to surgical intervention (7 resection, 3 transplant) and showed longer OS (p = 0.027). The 1-year and 3-year OS for patients who received surgery were 100% and 62.5% (95% CI: 14.2-89.3%), respectively. Age (p = 0.028), Eastern Cooperative Oncology Group performance status (p = 0.030), and objective radiologic response (p=0.014) are associated with OS. Two ≥grade 3 hyperbilirubinemia, anemia, and one pleuro-biliary fistula occurred post-SIRT.

CONCLUSIONS

SIRT for localized iCCA is safe and effective in achieving radiological response, downstaging to surgery and transplant, and resulting in pathologic necrosis.

CLINICAL RELEVANCE STATEMENT

Selective internal radiation therapy should be considered for patients with localized and locally advanced intrahepatic cholangiocarcinoma.

KEY POINTS

• The effectiveness of radioembolization for intrahepatic cholangiocarcinoma (iCCA) can be underestimated given the inclusion of extrahepatic disease. • Radioembolization is safe and effective for local and locally advanced iCCA. Age, Eastern Cooperative Oncology Group performance status, and radiologic response are associated with survival. • Radioembolization should be considered for patients with localized and locally advanced iCCA.

Modified Radiation Lobectomy Strategy of Radioembolization for Right-Sided Unresectable Primary Liver Tumors

PURPOSE

To assess the safety and effectiveness of using modified radiation lobectomy (mRL) to treat primary hepatic tumors located in the right hepatic lobe (segments V-VIII) and determine future liver remnant (FLR) hypertrophy.

METHODS

A retrospective review was performed at a single institution to include 19 consecutive patients (7 Female, 12 Male) who underwent single-session mRL for right sided primary hepatic tumors: 15 received segmentectomy plus lobectomy (segmental dose >190 Gy and lobar dose >80 Gy); 4 were treated with the double-segmental approach (dominant segments >190 Gy and non-dominant segments > 80 Gy). Treated tumors included 13 hepatocellular carcinoma (HCC), 4 cholangiocarcinoma (CCA), and 2 mixed-type HCC-CCA with a median dominant tumor size of 5.3 cm (Interquartile range [IQR]: 3.7-7.3cm). FLR of the left hepatic lobe was measured at baseline, T1 (4-8 weeks), T2 (2-4 months), T3 (4-6 months), and T4 (9-12 months).

RESULTS

Objective tumor response and tumor control were achieved in 17/19 (89.5%) and 18/19 (94.7%) patients, respectively. FLR hypertrophy was observed at T1 (median 47.8%, p=0.0245), T2 (median 48.4%, p=0.0120), T3 (median 50.4%, p=0.0147), and T4 (median 59.1%, p=0.00023). Non-cirrhotic patients demonstrated greater hypertrophy by 6-month (median 55.8% vs 47.2%, p=0.0310). One patient developed a grade 3 adverse event (ascites requiring paracentesis) at 1-month follow-up. Grade 2 or above serum toxicities are associated with worse baseline Child-Pugh Score, serum albumin, and total bilirubin (p<0.05). Among 7 patients who underwent neoadjuvant mRL, two underwent resection and one received liver transplant.

CONCLUSION

mRL appears safe and effective for treatment of right-sided primary hepatic tumors with the benefit of promoting FLR hypertrophy.

Single center outcomes from parenchymal-sparing resections and microwave ablations for neuroendocrine tumor liver metastases

BACKGROUND

Reported outcomes after surgical debulking in patients with advanced neuroendocrine tumor liver metastases (NETLM) are sparse.

METHODS

NETLM patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function, complications, symptom response, and progression-free survival were examined.

RESULTS

1069 liver lesions were debulked from 53 patients using a combination of parenchymal-sparing resections (PSR) and ultrasound-guided microwave ablations (MWA). Post-operative transaminitis and thrombocytopenia were common, and severity correlated with increasing number of lesions. Laboratory markers for synthetic liver function did not differ according to the number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3 or 4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to progression was 10.9 months.

CONCLUSIONS

PSR with MWA for large numbers of NETLM is safe and effective for symptom control and does not affect synthetic liver function.

SWOG 1609 cohort 48: anti-CTLA-4 and anti-PD-1 for advanced gallbladder cancer

INTRODUCTION

Most patients with advanced gallbladder cancer are treated with multiagent chemotherapy. Immune checkpoint inhibitors offer the possibility of a durable response with less toxicity. This prospective, multicenter, open-label study was designed to evaluate the anticancer activity of nivolumab plus ipilimumab in patients with advanced gallbladder cancer.

METHODS

Nineteen patients with advanced gallbladder cancer refractory to ≥1 previous therapy received nivolumab 240 mg intravenously every 2 weeks and ipilimumab 1 mg/kg intravenously every 6 weeks until disease progression or unacceptable toxicity. The primary end point was confirmed radiographic overall response rate (ORR) (complete response [CR] + partial response [PR] confirmed on subsequent scan); secondary end points included unconfirmed overall response, clinical benefit rate (confirmed and unconfirmed responses + stable disease >6 months), progression-free survival, overall survival, and toxicity.

RESULTS

The confirmed ORR was 16% (CR, n = 1 [5%]; PR, n = 2 [11%]); all were microsatellite stable, and the confirmed CR had undetectable programmed death-ligand 1 by immunohistochemistry. The unconfirmed ORR and clinical benefit rates were both 32%. The median duration of response was 14.8 months (range, 4-35.1+ months). The 6-month progression-free survival was 26% (95% CI, 12-55). The median overall survival was 7.0 months (95% CI, 3.9-19.1). The most common toxicities were fatigue (32%), anemia (26%), and anorexia (26%). Aspartate aminotransferase elevation was the most common grade 3/4 toxicity (11%). There was 1 possibly related death (sepsis with attendant hepatic failure).

CONCLUSIONS

Ipilimumab plus nivolumab was well tolerated and showed modest efficacy with durable responses in previously treated patients with advanced gallbladder cancer.

CLINICAL TRIAL REGISTRATION

NCT02834013 (ClincialTrials.gov).

PLAIN LANGUAGE SUMMARY

This prospective study assessed the efficacy and safety of nivolumab plus ipilimumab in 19 patients with advanced gallbladder cancer refractory to previous therapy. The combination demonstrated modest efficacy with a 16% confirmed overall response rate, durable responses, and manageable toxicities, suggesting potential benefits for this challenging patient population.

Segmental Yttrium-90 Radioembolization Using Glass Microspheres Greater than 400 Gray for the Treatment of Intrahepatic Cholangiocarcinoma: A Preliminary Experience

Radiation segmentectomy with a dose of >190 Gy using yttrium-90 (90Y) glass microspheres for intrahepatic cholangiocarcinoma (iCCA) has been shown to be safe and effective. The present study further increased the dose to >400 Gy for treatment of iCCA as complete pathologic necrosis has been shown in hepatocellular carcinoma using this ablative approach. A total of 10 patients with 13 tumors (median size, 5.3 cm; range, 1.5-13.6 cm) at a single institution underwent >400-Gy segmental radioembolization. Objective response was achieved in all tumors (13 of 13, 100%). One patient developed a Grade 3 or greater major adverse event (stroke and hepatic decompensation). One patient was bridged to transplant (>95% pathologic necrosis), whereas another underwent resection (>99% necrosis). Contralateral hypertrophy was observed in 6 out of 6 patients treated with modified lobectomy dosing, with a functional liver reserve increase from a median of 31.5% to 57.1%. The present report suggests that segmental transarterial radioembolization with >400 Gy is feasible in terms of safety and effectiveness for treating iCCA.

Abstract 1126: Disease monitoring with comprehensive genomics provides evidence of mechanism of action and immune evasion in patients receiving an individualized neoantigen cancer vaccine

Therapeutic vaccines hold promise to broaden the potency of immune checkpoint blockade (ICB) therapy in tumors lacking immune reactivity. A heterologous chimpanzee adenovirus (ChAd68) and self-amplifying mRNA (samRNA)-based individualized neoantigen vaccine regimen in combination with nivolumab 480 mg IV and ipilimumab 30mg SC (NCT03639714) has previously demonstrated safety, durable immunogenicity, and clinical benefit in patients with previously treated metastatic disease. Genomic correlates of response were studied over time in 29 patients (13 MSS-CRC, 13 GEA, 3 NSCLC) to understand novel mechanisms of action. Exome and transcriptome sequencing from archival biopsies was used for neoantigen selection. Monthly circulating tumor DNA (ctDNA) samples were collected for monitoring using a comprehensive tumor-naïve and tumor-informed hybrid-capture based ctDNA assay. Paired pre- and post-vaccine tumor transcriptomes were analyzed for 10 patients with 6 having accompanying DNA T cell receptor Β CDR3 repertoire sequencing (TCRseq) in biopsies and longitudinal PBMCs. Prior to vaccination patient tumors were not enriched for immune infiltration or tumor mutation burden (TMB), median 4.3 mut/Mb (range: 2-17 mut/Mb). Minimal neoantigen and mutation drift was observed with a median of 92.5% of neoantigens (range: 45-100%) and a median of 84% (range: 24-99%) of individual mutations detected in biopsies and ctDNA. Notably, paired pre- and post-vaccine biopsy gene expression analyses show upregulation in gene signatures associated with immune infiltration aligning with evidence of T cell expansion measured by significantly expanding CDR3 clonotypes (p &lt0.01). Longitudinal TCRseq in PBMCs demonstrate vaccine induced TCR repertoire dynamics and expanding and contracting clones observed in tumor biopsies could be monitored throughout treatment. In 4 patients the most drastic TCR repertoire changes were observed at time points measured after a 2nd dose of ChAd68. Lastly, we observe evidence of acquired immune evasion through ctDNA monitoring in two patients each following a year of study treatment. One GEA patient acquired HLA-LOH after remaining stable on treatment and one MSS-CRC with a molecular response (MR) for &gt7 months acquired novel biallelic loss-of-function mutations in TAP1 following 1 year of study treatment. We demonstrate that our neoantigen-directed immunotherapy regimen drives durable immune pressure on the tumor in patients with advanced disease where CPI alone has provided minimal benefit. Further, the evidence of acquired resistance supports the induction of immune pressure on tumors following individualized neoantigen vaccination. Comprehensive ctDNA longitudinal monitoring enables real-time assessment of clinical response and acquired resistance.

Citation Format: Desiree Schenk, Rita Zhou, Olivia Petrillo, Alexis Mantilla, Italo Faria do Valle, Steven Maron, Brian S. Henick, Chih-Yi Liao, Daniel V.T. Catenacci, Sameek Roychowdhury, Benjamin Solomon, Alexander I. Spira, Ankur Dhanik, Andrew R. Fergusson, Karin Jooss, Matthew Davis. Disease monitoring with comprehensive genomics provides evidence of mechanism of action and immune evasion in patients receiving an individualized neoantigen cancer vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1126.

Light It Up! The Use of DOTATATE in Diagnosis and Treatment of Neuroendocrine Neoplasms

Radiolabeled somatostatin analogs are increasingly used in the diagnosis and treatment of neuroendocrine tumors. Diagnostic imaging with 68Ga-DOTATATE PET/CT has demonstrated the improved sensitivity in detecting primary and metastatic neuroendocrine lesions compared with conventional imaging and prior generation somatostatin receptor imaging. Peptide receptor radionuclide therapy with 177Lu-DOTATATE is now frequently included in the management of neuroendocrine neoplasms, with prospective randomized control studies demonstrating its beneficial impact on survival and quality of life. Nonetheless, peptide rector radionuclide therapy is still considered palliative rather than curative and may be accompanied by adverse effects.

Phase 1 Randomized Trial of Stereotactic Body Radiation Therapy Followed by Nivolumab plus Ipilimumab or Nivolumab Alone in Advanced/Unresectable Hepatocellular Carcinoma

PURPOSE

Immunotherapy has emerged as a promising therapeutic option for advanced or unresectable hepatocellular carcinoma (HCC). However, survival remains poor with only a subset of patients deriving benefit. This trial investigated the safety and efficacy of stereotactic body radiation therapy (SBRT) with immunotherapy in HCC.

METHODS AND MATERIALS

In this multicenter phase 1 randomized trial, patients with advanced or unresectable HCC received liver SBRT (40 Gy in 5 fractions) followed by either nivolumab alone or nivolumab plus ipilimumab. The primary endpoint was dose-limiting toxicity occurring within 6 months of SBRT. Secondary endpoints included overall response rate, progression-free survival, overall survival (OS), distant disease control, and local control of the irradiated tumor. Disease status and response endpoints were assessed radiographically every 8 weeks until progression or initiation of nonprotocol therapy. Response was determined using both RECIST (Response Evaluation Criteria in Solid Tumors) 1.1 and iRECIST.

RESULTS

Fourteen patients were enrolled across 3 centers. Thirteen patients were evaluated for study endpoints. The study was closed early because of slow accrual. The median follow-up time was 42.7 months. Dose-limiting toxicities within 6 months occurred in 2 (15.4%) of 13 patients: 1 of 6 patients in the nivolumab arm (16.7%; 90% confidence interval [CI], 0.9%-58.2%) and 1 of 7 patients in the nivolumab plus ipilimumab arm (14.3%; 90% CI, 0.7%-52.1%). Grade 3 adverse events occurred in 8 (61.6%), 5 (71.4%), and 3 (50.0%) patients in the overall nivolumab plus ipilimumab and nivolumab cohorts. Grade 3 hepatotoxicity occurred in 4 (30.8%), 3 (42.9%), and 1 (16.7%) patients in the respective cohorts. Clinical outcomes favored the nivolumab plus ipilimumab arm compared with nivolumab alone, including an overall response rate of 57% (4 of 7 patients; 90% CI, 23%-87%) versus 0% (0 of 6 patients; 90% CI, 0%-39%), median progression-free survival of 11.6 months (90% CI, 4.5 months to not reached) versus 2.7 months (90% CI, 1.3-4.7 months), and median OS of 41.6 months (90% CI, 4.5 months to not reached) versus 4.7 months (90% CI, 2.0-16.2 months) (all P < .05). With combination immunotherapy, 3-year OS was 57% (90% CI, 23%-81%), with 2 patients alive after 42.7 months without progression and negative PET.

CONCLUSIONS

In this first prospective trial investigating the combination of SBRT and immunotherapy for HCC, multimodal therapy demonstrated acceptable safety. SBRT with nivolumab plus ipilimumab compared favorably to outcomes of immunotherapy alone and warrants further investigation.

Yttrium-90 Radioembolization and Concomitant Systemic Gemcitabine, Cisplatin, and Capecitabine as the First-Line Therapy for Locally Advanced Intrahepatic Cholangiocarcinoma

PURPOSE

To determine the safety and effectiveness of yttrium-90 transarterial radioembolization (TARE) combined with systemic gemcitabine, cisplatin, and capecitabine for the first-line treatment of locally advanced intrahepatic cholangiocarcinoma (iCCA).

MATERIALS AND METHODS

Data of 13 patients with treatment-naïve, locally advanced iCCA treated with a downstaging protocol using gemcitabine, cisplatin, TARE, and capecitabine were retrospectively reviewed. Overall survival (OS), local tumor response (modified Response Evaluation Criteria in Solid Tumors), progression-free survival (PFS), technical adverse events, and toxicity were measured.

RESULTS

Calculated from the time of diagnosis, the median OS was 29 months (95% confidence interval [CI], 15 to not reached), with a 1-year OS of 84.6% (95% CI, 52.2%-95.9%) and 2-year OS of 52.9% (95% CI, 20.3%-77.5%). The median OS values were 24 months (95% CI, 8 to not reached) and 21 months (95% CI, 5 to not reached) from the time of initial cycle of chemotherapy and TARE, respectively. Patients who were downstaged to surgery (n = 7, 53.8%) had a more favorable OS (median OS, not reached vs 15 months; P = .0221). Complete and partial radiologic responses were achieved in 5 (38.5%) and 6 (46.2%) patients, respectively. The median PFS was 13 months (95% CI, 12 to not reached). Although no serum toxicity with Grade >2 occurred within 3 months after TARE, 1 patient was no longer a surgical candidate given suboptimal nutrition status despite successful downstage on imaging studies. Two patients required a reduced dose or delay of post-TARE chemotherapy.

CONCLUSIONS

First-line combination therapy with TARE and systemic gemcitabine, cisplatin, and capecitabine is an effective treatment with an acceptable safety profile for iCCA with a high rate of downstaging to resection.

A Reverse Mutation E143K within the PrM Protein of Zika Virus Asian Lineage Natal RGN Strain Increases Infectivity and Cytopathicity

Zika virus (ZIKV) is a positive-sense single-stranded RNA virus in the Flaviviridae, which is classified into two different lineages Asian and African. The outbreak of ZIKV Asian lineage isolates in 2015–2016 is associated with the increase in cases with prenatal microcephaly and Guillain–Barré syndrome, and has sparked attention throughout the world. Genome sequence alignment and the analysis of Asian and African lineage isolates indicate that amino acid changes, particular in positively charged amino acid substitutions in the pr region of prM protein might involve a phenotypic change that links with the global outbreak of ZIKV Asian-lineage. The study generated and characterized the virological properties of wild type and mutants of single-round infectious particles (SRIPs) and infectious clones (i.c.s) of ZIKV Asian-lineage Natal RGN strain, and then identified the function of amino acid substitutions at the positions 139 [Asn139→Ser139 (N139S)] and 143 [Glu143→Lys143 (E143K)] in ZIKV polyproteins (located within the pr region of prM protein) in the infectivity and cytopathogenicity. The E143K SRIP and i.c. of Natal RGN strain exhibited relatively higher levels of cytopathic effect, EGFP reporter, viral RNA and protein synthesis, and virus yield in three types of human cell lines, TE617, SF268 and HMC3, compared to wild type (WT), N139S SRIPs and i.c.s, which displayed more efficiency in replication kinetics. Additionally, E143K Natal RGN i.c. had greater activities of virus attachment and entry, yielded higher titers of intracellular and extracellular virions, and assembled the E proteins near to the plasma membrane in infected cells than the other i.c.s. The results indicate that the positively charged amino acid residue Lys143, a conserved residue in the pr region of prM of ZIKV African lineages, plays a crucial role in viral replication kinetics, including viral attachment, entry, assembly and egress. Thus, the negatively charged amino acid residue Glu143 within the pr region of prM leads to an alteration of the phenotypes, in particular, a lower replication efficiency of ZIKV Asian-lineage isolates with the attenuation of infectivity and cytopathicity.

Abstract 1238: Comprehensive ctDNA monitoring provides early signal of clinical benefit with a novel personalized neoantigen directed immunotherapy for late-stage cancer patients

Neoantigen directed immunotherapy holds promise to increase the likelihood of patients with solid tumor devoid of immune infiltration benefiting from immune checkpoint immunotherapy (CPI). A heterologous prime-boost vaccination approach consisting of Chimpanzee Adenovirus (ChAd) prime and multiple self-amplifying mRNA (SAM) boosts, delivering 20 neoantigens, has been evaluated in a Phase 1/2 clinical trial in late-stage solid tumor patients in combination with nivolumab and ipilimumab (NCT03639714). Neoantigen dynamics, tumor burden and genomic correlates of response were studied over time in 20 patients (8 GEA, 2 NSCLC, 10 MSS-CRC). Exome sequences from archival (sample used for neoantigen selection), baseline (start of immunization) and on-treatment biopsies were analyzed for 20, 16 and 10 patients respectively. Paired pre- and post-vaccine tumor transcriptomes were analyzed for 6 patients. Personalized capture baits were designed for all non-synonymous mutations detected in archival biopsies (mean 146; range: 67-402) for ctDNA monitoring. Longitudinal ctDNA samples were collected monthly on treatment (mean 7; range: 1-18). ctDNA duplex UMI libraries were captured and sequenced to a target mean raw depth &gt;80,000x and reduced to 3x per strand consensus duplex reads. The majority of vaccine neoantigens were detected in ctDNA (87%; range 45%-100%) and mean neoantigen variant allele frequency (VAF) strongly correlated with all monitored mutations VAF (R2 = 0.90, p &lt; 0.0001) through treatment. The percentage of vaccine neoantigens detected was higher than that for all monitored mutations in the same samples with a median of 80% (21%-98%) in ctDNA and 70% (44%-100%) in biopsies. Five of 9 MSS-CRC patients with measurable baseline ctDNA achieved molecular responses (MR, &gt;50% reduction in ctDNA from baseline) that correlated with OS and PFS, and in some patients, was accompanied by radiologic tumor shrinkage. One MSS-CRC patient with MR for &gt;7 months acquired novel biallelic loss-of-function mutations in TAP1 following 1 year of study treatment. Differential gene expression analysis from paired pre- and post-vaccine biopsies (including 2 MSS-CRC pairs with MR) demonstrated significant upregulation in gene signatures associated with immune-inflamed tumor microenvironments including interferon alpha and gamma responses. We demonstrate that tumor-informed neoantigen selection and vaccine manufacturing while patients receive chemotherapy is feasible, since the majority of neoantigens are retained in the tumor post-chemotherapy. Further, neoantigen-directed immunotherapy appears to drive clinical benefit in patients with advanced MSS-CRC tumors, where CPI alone has provided minimal benefit. Comprehensive ctDNA longitudinal monitoring enables real time assessment of clinical response and acquired resistance.

Citation Format: Desiree Schenck, Rita Zhou, Alexis Mantilla, Oliver Spiro, Taylor Patch, Adrienne Johnson, Daniel Navarro Gomez, Brian S. Henick, Chih-Yi Liao, Sameek Roychowdhury, Steve Maron, Benjamin Solomon, Alexander I. Spira, Daniel V. Catenacci, Andrew R. Fergusson, Raphael F. Rousseau, Karin Jooss, Matthew J. Davis. Comprehensive ctDNA monitoring provides early signal of clinical benefit with a novel personalized neoantigen directed immunotherapy for late-stage cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1238.

Outcomes in high-grade neuroendocrine carcinomas (HG-NEC) of the gastrointestinal (GI) tract with modern therapies

e15609

Background: HG-NEC of the GI tract are rare and aggressive neoplasms with poor prognosis. Approximately 37.5% of extra-pulmonary NEC are of the GI origin and are most commonly located in esophagus, stomach, pancreas and colon (1,2). Median survival of 7.5 months, with range of 5.7 months to 25.1 months has been reported (2). However, data regarding response to immunotherapy, as well as response to molecularly directed therapies are sparse. In this study, we conducted a retrospective review of GI tract HG-NEC with objective to assess role of modern diagnostics and therapies in clinical outcomes. Methods: We identified 14 patients with GI tract HG-NEC who received care at University of Chicago Medical Center (UCMC). Electronic medical records were reviewed for disease stage, treatments and clinical course. We reviewed available next generation sequencing (NGS) and circulating tumor DNA (ct-DNA) test results. In this cohort, UCMC’s NGS panel: Oncoplus was available and Guardant 360 results were reviewed for liquid biopsy. Results: In our initial review, site of origin included right side of colon (46%), left sided colon (46%), and anus/anorectal (15%). Median overall survival (mOS) ranged from 1.3 months to 81.3 months, and notably the median response to chemo-immunotherapy (IO) was 7.9 months (table 1). Notably one patient received maintenance therapy with immunotherapy alone with progression of disease (POD) in 3 weeks. Six patients had NGS results of which three (50%) had therapeutic targetable alterations (Table). Two patients had liquid biopsy done, of which one had targetable alterations and the other had no tumor related alterations detected. Of the two patients with targetable lesions, one patient has received targeted therapy with POD in 1.2 months and median OS 8.8 months; the other is in the process of initiating targeted therapy. Conclusions: To our knowledge, this is the first report to show a response to combination chemo-immunotherapy and targeted therapies in HG-NEC of GI tract. We are collaborating with other institutions to collate outcomes to similar therapy approaches in this patient cohort. With our study, we hope to inform future therapies and innovation in this important disease.

Epidemiological characteristics of central nervous system tumors in children: a 5-year review of 3180 cases from Beijing Tiantan Hospital

Background

To describe the epidemiological characteristics of central nervous system (CNS) tumors in children, based on the neurosurgery department of Beijing Tiantan Hospital.

Methods

From January 2015 to December 2019, 3180 children were histopathologically diagnosed with CNS tumors based on the 2016 World Health Organization (WHO) classification of tumors. Patients were 0 to 15 years old. We analyzed age-related gender preferences, tumor locations, and the histological grades of the tumors. In addition, the epidemiological characteristics of the five most common intracranial tumors were compared to the previous studies.

Results

In this study, intracranial and spinal tumors account for 96.4% (3066) and 3.6% (114) of all tumors, with a preponderance of supratentorial tumors (57.9%). Among all pediatric patients, low-grade tumors comprise 67.1% (2 135). The integral gender ratio of males to females is 1.47: 1 and the average age of patients is 7.59 years old. The five most common intracranial tumors are craniopharyngioma (15.4%), medulloblastoma (14.3%), pilocytic astrocytoma (11.8%), diffuse astrocytoma (9.8%), and anaplastic ependymoma (4.8%).

Conclusions

Due to the lack of national data on childhood brain tumors, we used a large nationally representative population sample based on the largest pediatric neurosurgery center in China. We analyzed the data of the past 5 years, reflecting the incidence of CNS tumors in Chinese children to a certain extent, and laying a data foundation for subsequent clinical studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41016-022-00279-z.

Laryngotracheal resection after B-Raf proto-oncogene inhibition for anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is a rare but aggressive neoplasm that often presents as advanced inoperable disease. Patients with B-Raf proto-oncogene (BRAF) v600e mutated ATC who receive neoadjuvant Dabrafenib/Trametinib have improved rates of microscopically margin negative resection and durable locoregional control. However, this has not been evaluated in the setting of tracheal resection and primary reconstruction. Here we demonstrate the safety and efficacy of laryngotracheal resection and reconstruction after Dabrafenib/Trametinib for locoregionally advanced BRAF v600e mutated ATC.

Correlation of circulating tumor DNA (ctDNA) with clinical outcomes in appendiceal cancers (AC)

29

Background: Appendiceal Cancers are a heterogenous group of rare tumors with distinct histopathologic and genomic alterations. These often have peritoneal spread that might not be easily detected on current imaging modalities, and conventional tumor markers may not lend diagnostic support. Hence, novel diagnostic techniques are needed. Measurement of ctDNA for recurrence risk prediction, response to therapy and and early diagnosis is a promising technique. However, limited published data exist in AC to validate the role and utility of ctDNA in clinical practice. Here we present a single institution experience of ctDNA analysis in patients with AC. Methods: ctDNA measurements of 37 pts with stage II-IV AC treated between 1/1/2019 and 9/15/2021 were reviewed retrospectively. ctDNA analysis was done using Signatera bespoke mPCR NGS assay. ctDNA results were compared to crossectional imaging, CEA levels, and clinical evaluation. Results: 19/37 patients (51%) had at least one positive ctDNA test result. Of those, 8 had testing done during the surveillance setting (two with grade 3, one with grade 2, two with grade 1, and three with unknown grade). Of those, 5 pts (62.5%) had positive ctDNA detected, while 33.33% had elevated CEA level, 25% had radiographic and 42.9% had clinical evidence of recurrence (Table). 7/14 (50%) pts had high-grade pathology and positive ct-DNA, 3/6 (50%) patients had low-grade (grade 1) pathology and positive ct-DNA findings. 4 patients had longitudinal ct-DNA measurements available which correlated well with their disease course. Median duration to recurrence (radiographic or laparoscopic) was 376 days. Median duration to the first positive ctDNA test was 370 days. Median duration to positive CEA after initial treatment was 475 days. Conclusions: Measurement of ctDNA can be a useful tool to follow disease course and to guide management decision-making in patients with AC. Prospective studies with serial measurements of ctDNA are planned. [Table: see text]

A phase 1b/2 study of VS-6766 in combination cetuximab in patients (pts) with advanced KRAS mt colorectal cancer (CRC)

TPS219

Background: KRAS mutations (mts) are present in about 45% of CRC and predict lack of response to anti-EGFR therapy like cetuximab. Limited therapy options exist for pts after prior 5-FU based regimens. Regorafenib or TAS-102 is commonly used however, the modest clinical benefit, and toxicity limit their use. Novel therapies are needed for pts at this point in their disease course. KRAS G12D and G12V mts occur in 11-12% and 9-10% of CRC, respectively, whereas G12C mts occur in 3-4% of CRCs . KRAS G12C mts occur in 3-4% of CRCs. Recently, results of phase 1/2 KRYSTAL-1 study were reported. Adagrasib (a KRAS G12C inhibitor) was used with/without cetuximab in heavily pretreated CRC pts harboring KRAS G12C mts. The objective response rate (ORR) and disease control rate (DCR) was 43% and 100% (resp.) in pts receiving cetuximab and adagrasib (28 evaluable pts), and 22% and 87%, resp., in those receiving adagrasib alone (42 evaluable pts). Phase 1b CodeBreaK101 study evaluating sotorasib ( KRAS G12C inhibitor) and panitumumab (anti-EGFR) combination in KRAS G12C mt CRC showed 15.4% confirmed ORR and 26.9% unconfirmed ORR. These data are encouraging, suggesting EGFR inhibition in combination with downstream KRAS inhibition may represent important therapeutic strategy for this disease. KRAS mts lead to constitutive activation of the MAPK pathway signaling and cell activation. VS-6766 is a novel dual RAF/MEK inhibitor which has shown activity in KRAS mutated tumors. Combination of EGFR inhibition and VS-6766 may overcome resistance of KRAS mt CRC cancers to EGFR inhibition alone. Preclinically, VS-6766 and EGFR inhibition showed synergy in KRAS mt CRC cell lines, including cell lines harboring KRAS G12D and G12V mts, and CRC PDX of KRAS G12V mt CRC showed tumor regression with this combination. These data support the development of VS-6766 with anti-EGFR therapy in KRAS mt CRC warranting this phase 1 study to evaluate safety and efficacy of this combination in clinical settings. Methods: This is an open label, single arm study evaluating VS-6766 with cetuximab in pts with KRAS mt advanced CRC. Phase 1b primary endpoints include safety and tolerability, and maximum tolerated dose and recommended phase 2 dose determination. ORR is the primary endpoint of the Phase 2 study. Secondary endpoints include OS and PFS. There will be upto 4 dose levels tested. Three de-escalation doses to find the optimal cetuximab dose, and one dose escalation of VS-6766, are planned. Eligible pts include those with metastatic CRC and progression after 5-FU, oxaliplatin, irinotecan and VEGFi therapy. Based on prior studies, dermatologic, gastrointestinal, ocular and CPK elevation have been the main toxicities noted with VS-6766. The study is funded by research grants from Verastem Oncology. Cetuximab will be supplied by Eli Lilly.

Safety and efficacy of combining genotype-guided irinotecan (Iri) with 5FU, leucovorin (LV), oxaliplatin (Ox), and docetaxel (Tax) (gFOLFOXIRITAX): The I-FLOAT phase 1 dose-escalation study for advanced upper GI cancers

316

Background: 5FU, Ox, Iri, and Tax are each active in upper GI cancers. Triplet cytotoxic therapies (txs) improved survival compared to doublets/singlets. However, combination of all 4 agents (FOLFOXIRITAX) has not been studied. UGT1A1 polymorphisms reduce UGT enzymatic activity predisposing to Iri toxicity. We sought to determine the maximum tolerated dose (MTD) in the 1st month of tx among each of the low (L), intermediate (I) and high (H) risk UGT1A1 genotype (UGT) groups. Methods: Previously untx’d advanced upper GI cancer patients (pts) with ECOG PS 0/1 received gFOLFOXIRITAX (+ trastuzumab if HER2+) with pegfilgrastim. 5FU 2400mg/m2 over 46 hrs, LV 400mg/m2, Ox 85mg/m2, and Tax 25mg/m2 were given IV Q14 days. UGT-L, I, and H risk groups received starting Iri dose levels (DL1) of 120, 105 and 45mg/m2, respectively; Iri doses were escalated in each UGT group by 15mg/m2 increments and Tax to DL2 of 37.5mg/m2 using a I3+3 novel design (Liu & Ji. J Biopharm Stat 2020). Other endpoints included overall safety (thru up to 8 cycles before maintenance 5FU +/- Iri/tras), ORR (RECIST1.1), & ctDNA response (> 50% decrease in highest MAF) by G360 (Guardant Health). Results: From 6/30/2020-8/6/2021 20 pts (8F, 12M) enrolled: median age 50 (range 21-76); 8 ECOG PS 1, UGT-L:I:H with 3:14:3 pts; 10 esophageal, 6 gastric, 2 pancreatic, 1 unknown GI primary and 1 bile duct cancer; 2 pts HER2+; 18 metastatic, 2 locally advanced unresectable. The median (range) of albumin and neutrophil-to-lymphocyte ratio (NLR) were 3.9 mg/dL (3.3-4.6) and 4.28 (1.89-27.6), respectively; 80% (16/20) of pts had a NLR > 2.88, a poor prognostic marker. Dose limiting toxicities (DLTs) were seen in 4 pts: one G3 diarrhea (UGT-H, DL1/DL1 Iri/Tax), two G3 sepsis not neutropenic (one UGT-I, DL2/DL2 Iri/Tax; and one UGT-I, DL3/DL1 Iri/Tax) and one G3 fatigue (UGT-I DL2/DL2 Iri/Tax). MTD has not been reached in any UGT TAX DL1 cohorts to date; currently enrolling UGT-H Iri/Tax DL1/DL1, UGT-I DL4/DL1, & UGT-L DL3/DL1. Any Gr tx related toxicities in ³ 10% pts thru up to 8 cycles: nausea (70%), fatigue (70%, 5% G3), diarrhea (65%, 5% G3), anorexia (50%), peripheral neuropathy (30%, 5% G3), anemia (30%), thrombocytopenia (25%), elevated LFTs (25%), hyponatremia (25%), vomiting (20%), mucositis (20%, 5% G3), hyperglycemia (20%), edema (15%), alopecia (15%), hypocalcemia (15%) and dysgeusia (10%). Of evaluable pts across all cohorts, PR/CR was seen in 13/16 (81%) patients, with 2 (12.5%) SD and 1 (6.25%) PD for a disease control rate of 94%. Of evaluable pts, best ctDNA response was seen in 12/13 (92%). Conclusions: gFOLFOXIRITAX demonstrated tolerability at initial dose levels of Iri/Tax, with dose escalation continuing. Efficacy is promising and could be an aggressive approach in upper GI cancers having high relapse risk in curative-intent settings. Clinical trial information: NCT04361708.

Phase II Prospective, Open-Label Randomized Controlled Trial Comparing Standard of Care Chemotherapy With and Without Sequential Cytoreductive Interventions for Patients with Oligometastatic Foregut Adenocarcinoma and Undetectable Circulating Tumor Deoxyribose Nucleic Acid (ctDNA) Levels

BACKGROUND

Metastatic adenocarcinomas of foregut origin are aggressive and have limited treatment options, poor quality of life, and a dismal prognosis. A subset of such patients with limited metastatic disease might have favorable outcomes with locoregional metastasis-directed therapies. This study investigates the role of sequential cytoreductive interventions in addition to the standard of care chemotherapy in patients with oligometastatic foregut adenocarcinoma.

METHODS

This is a single-center, phase II, open-label randomized clinical trial. Eligible patients include adults with synchronous or metachronous oligometastatic (metastasis limited to two sites and amenable for curative/ablative treatment) adenocarcinoma of the foregut without progression after induction chemotherapy and having undetectable ctDNA. These patients will undergo induction chemotherapy and will then be randomized (1:1) to either sequential curative intervention followed by maintenance chemotherapy versus routine continued chemotherapy. The primary endpoint is progression-free survival (PFS), and a total of 48 patients will be enrolled to detect an improvement in the median PFS in the intervention arm with a hazard ratio (HR) of 0.5 with 80% power and a one-sided alpha of 0.1. Secondary endpoints include disease-free survival (DFS) in the intervention arm, overall survival (OS), ctDNA conversion rate pre/post-induction chemotherapy, ctDNA PFS, PFS2, adverse events, quality of life, and financial toxicity.

DISCUSSION

This is the first randomized study that aims to prospectively evaluate the efficacy and safety of surgical/ablative interventions in patients with ctDNA-negative oligometastatic adenocarcinoma of foregut origin post-induction chemotherapy. The results from this study will likely develop pertinent, timely, and relevant knowledge in oncology.

Phase I Study of Stereotactic Body Radiotherapy plus Nivolumab and Urelumab or Cabiralizumab in Advanced Solid Tumors

PURPOSE

CD137 agonism and CSF1R blockade augment stereotactic body radiotherapy (SBRT) and anti-programmed death-1 in preclinical models. We evaluated the safety and efficacy of SBRT with nivolumab+urelumab (CD137 agonist) or nivolumab+cabiralizumab (CSF1R inhibitor).

PATIENTS AND METHODS

This phase I clinical trial enrolled patients with advanced solid tumors that had progressed on standard therapies. SBRT was delivered to 1-4 metastases with nivolumab+urelumab or nivolumab+cabiralizumab given concurrently and following SBRT. Dose-limiting toxicity (DLT) was the primary endpoint with anatomic location-specific SBRT doses deemed safe if ≤33% DLT frequency was observed. Secondary endpoints included RECISTv1.1 response, progression-free survival (PFS), overall survival (OS), and molecular correlative studies.

RESULTS

Sixty patients were enrolled, and median follow-up for living patients is 13.8 months. Of these, 23 (38%) received SBRT+nivolumab+urelumab and 37 (62%) received SBRT+nivolumab+cabiralizumab. Seven patients (12%) experienced a DLT (n = 3 grade 3, n = 4 grade 4) in the following anatomic cohorts: abdominal/pelvic (3/17, 18%), liver (1/13, 8%), central lung (2/14, 14%), and peripheral lung (1/12, 8%). Of 41 patients radiographically evaluable for best overall response including 55 radiated and 23 unirradiated RECIST target lesions, 2 had complete responses (5%), 7 had partial responses (17%), 12 had stable disease (29%), and 20 had progression (49%). Median estimated PFS and OS are 3.0 months [95% confidence interval (CI), 2.9-4.8] and 17.0 months (95% CI, 6.8-undetermined), respectively. No patients with elevated pre-SBRT serum IL8 experienced a response.

CONCLUSIONS

SBRT to ≤4 sites with nivolumab+urelumab or nivolumab+cabiralizumab for treating advanced solid tumors is feasible with acceptable toxicity and modest antitumor activity.See related commentary by Rodriguez-Ruiz et al., p. 5443.

Deep learning prediction of BRAF-RAS gene expression signature identifies noninvasive follicular thyroid neoplasms with papillary-like nuclear features

Noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) are follicular-patterned thyroid neoplasms defined by nuclear atypia and indolent behavior. They harbor RAS mutations, rather than BRAFV600E mutations as is observed in papillary thyroid carcinomas with extensive follicular growth. Reliably identifying NIFTPs aids in safe therapy de-escalation, but has proven to be challenging due to interobserver variability and morphologic heterogeneity. The genomic scoring system BRS (BRAF-RAS score) was developed to quantify the extent to which a tumor's expression profile resembles a BRAFV600E or RAS-mutant neoplasm. We proposed that deep learning prediction of BRS could differentiate NIFTP from other follicular-patterned neoplasms. A deep learning model was trained on slides from a dataset of 115 thyroid neoplasms to predict tumor subtype (NIFTP, PTC-EFG, or classic PTC), and was used to generate predictions for 497 thyroid neoplasms within The Cancer Genome Atlas (TCGA). Within follicular-patterned neoplasms, tumors with positive BRS (RAS-like) were 8.5 times as likely to carry an NIFTP prediction than tumors with negative BRS (89.7% vs 10.5%, P < 0.0001). To test the hypothesis that BRS may serve as a surrogate for biological processes that determine tumor subtype, a separate model was trained on TCGA slides to predict BRS as a linear outcome. This model performed well in cross-validation on the training set (R2 = 0.67, dichotomized AUC = 0.94). In our internal cohort, NIFTPs were near universally predicted to have RAS-like BRS; as a sole discriminator of NIFTP status, predicted BRS performed with an AUC of 0.99 globally and 0.97 when restricted to follicular-patterned neoplasms. BRAFV600E-mutant PTC-EFG had BRAFV600E-like predicted BRS (mean -0.49), nonmutant PTC-EFG had more intermediate predicted BRS (mean -0.17), and NIFTP had RAS-like BRS (mean 0.35; P < 0.0001). In summary, histologic features associated with the BRAF-RAS gene expression spectrum are detectable by deep learning and can aid in distinguishing indolent NIFTP from PTCs.

A phase I/II trial to evaluate cabozantinib in patients with advanced hepatocellular carcinoma with Child-Pugh class B cirrhosis after first-line therapy

TPS357

Background: Hepatocellular carcinoma (HCC) is the 4th leading cause of cancer related death worldwide. HCC typically develops in patients with cirrhosis and has a 5-year survival estimate of 20%. Only patients with early stage disease may be eligible for a curative approach using local treatment and/or transplant. The majority of patient present with advanced HCC and will require systemic treatment for disease control. Several systemic therapies are FDA-approved for the treatment of HCC; however, they are only approved for patients with Child-Pugh class A cirrhosis. There are limited data and no approved second-line therapy for HCC with more advanced cirrhosis, including Child-Pugh class B, which represents a significant proportion of patients. The aim of this trial is to determine the safety and efficacy of cabozantinib, a multi-kinase inhibitor, in patients with HCC with Child-Pugh class B cirrhosis. Methods: This investigator-initiated, phase I/II study is enrolling 32 patients with advanced HCC, Child-Pugh B7 or B8, who have previously received first-line systemic treatment. Patients receive cabozantinib at one of 3 dose levels (20 mg, 40 mg, and 60 mg) with a starting dose level of 40 mg to evaluate the safety profile and obtain the recommended phase 2 dose (RP2D). The primary endpoint is assessment of dose-limiting toxicity with a null hypothesis greater than 35%. Secondary endpoints include ORR per RECIST v1.1, PFS, OS, and PK profile. Exploratory endpoints include whole exome/RNAseq analysis (including MET, VEGF, AXL, and immune signature), spatial profiling of immune markers by multiplex immunofluorescence, and specimen banking (tissue, blood and imaging). The trial design is based on the Time-To-Event modification of the Continual Reassessment Method (TiTE-CRM), which allows for continued monitoring of toxicity as a function of a dose-over-time, and is flexible with regard to the number of patients treated at a certain dose. The trial is open at University of Michigan as lead and coordinating site, and due to open at 3 additional high-volume centers. Clinical trial information: 04497038.

Cytoreductive Surgery for Selected Patients Whose Metastatic Gastric Cancer was Treated with Systemic Chemotherapy

BACKGROUND

The authors hypothesized that cytoreductive surgery (CRS, comprising gastrectomy combined with metastasectomy) in addition to systemic chemotherapy (SC) is associated with a better survival than chemotherapy alone for patients with metastatic gastric adenocarcinoma (MGA).

METHODS

Patients with MGA who received SC between 2004 and 2016 were identified using the National Cancer Database (NCDB). Nearest-neighbor 1:1 propensity score-matching was used to create comparable groups. Overall survival (OS) was compared between subgroups using Kaplan-Meier analyses. Immortal bias analysis was performed among those who survived longer than 90 days.

RESULTS

The study identified 29,728 chemotherapy-treated patients, who were divided into the following four subgroups: no surgery (NS, n = 25,690), metastasectomy alone (n = 1170), gastrectomy alone (n = 2248), and CRS (n = 620) with median OS periods of 8.6, 10.9, 14.8, and 16.3 months, respectively (p < 0.001). Compared with the patients who underwent NS, the patients who had CRS were younger (58.9 ± 13.4 vs 62.0 ± 13.1 years), had a lower proportion of disease involving multiple sites (4.6% vs 19.1%), and were more likely to be clinically occult (cM0 stage: 59.2% vs 8.3%) (p < 0.001 for all). The median OS for the propensity-matched patients who underwent CRS (n = 615) was longer than for those with NS (16.4 vs 9.3 months; p < 0.001), including in those with clinical M1 stage (n = 210). In the Cox regression model using the matched data, the hazard ratio for CRS versus NS was 0.56 (95% confidence interval [CI], 0.49-0.63). In the immortal-matched cohort, the corresponding median OS was 17.0 versus 9.5 months (p < 0.001).

CONCLUSIONS

In addition to SC, CRS may be associated with an OS benefit for a selected group of MGA patients meriting further prospective investigation.

Personalized Antibodies for Gastroesophageal Adenocarcinoma (PANGEA): A Phase II Study Evaluating an Individualized Treatment Strategy for Metastatic Disease

The one-year and median overall survival (mOS) rates of advanced gastroesophageal adenocarcinomas (GEA) are ∼50% and <12 months, respectively. Baseline spatial and temporal molecular heterogeneity of targetable alterations may be a cause of failure of targeted/immunooncologic therapies. This heterogeneity, coupled with infrequent incidence of some biomarkers, has resulted in stalled therapeutic progress. We hypothesized that a personalized treatment strategy, applied at first diagnosis then serially over up to three treatment lines using monoclonal antibodies combined with optimally sequenced chemotherapy, could contend with these hurdles. This was tested using a novel clinical expansion-platform type II design with a survival primary endpoint. Of 68 patients by intention-to-treat, the one-year survival rate was 66% and mOS was 15.7 months, meeting the primary efficacy endpoint (one-sided P = 0.0024). First-line response rate (74%), disease control rate (99%), and median progression-free survival (8.2 months) were superior to historical controls. The PANGEA strategy led to improved outcomes warranting a larger randomized study. SIGNIFICANCE: This study highlights excellent outcomes achieved by individually optimizing chemotherapy, biomarker profiling, and matching of targeted therapies at baseline and over time for GEA. Testing a predefined treatment strategy resulted in improved outcomes versus historical controls. Therapeutic resistance observed in correlative analyses suggests that dual targeted inhibition may be beneficial.This article is highlighted in the In This Issue feature, p. 211.

Novel Application of Iterative Hyperthermic Intraperitoneal Chemotherapy for Unresectable Peritoneal Metastases from High-Grade Appendiceal Ex-Goblet Adenocarcinoma

BACKGROUND

Peritoneal metastases (PMs) from appendiceal ex-goblet adenocarcinoma (AEGA) are associated with a poor prognosis. While cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been shown to prolong survival, the majority of patients are ineligible for complete cytoreduction. We describe a novel approach to the management of such patients with iterative HIPEC (IHIPEC).

METHODS

Patients with signet ring/poorly differentiated AEGA with high Peritoneal Cancer Index (PCI) and extensive bowel involvement underwent IHIPEC with mitomycin C at 6-week intervals for a total of three cycles. Survival outcomes for these patients were compared with patients with high-grade appendiceal tumors matched for tumor burden who were treated with other conventional approaches, i.e. systemic chemotherapy only (SCO) or complete CRS + HIPEC.

RESULTS

Between 2016 and 2019, seven AEGA patients with high PCI (median 32.5 [range 21-36]) underwent 18 IHIPEC cycles (median cycles per patient 3 [2-3]) in combination with systemic chemotherapy (median 2 lines [1-3], 12 cycles [10-28]). IHIPEC was delivered laparoscopically in 14/18 cases. Postoperatively, the median length of stay was 1 day (1-8 days), no procedure-related complications were reported, and five (28%) 90-day readmissions for bowel obstruction were documented. Median overall survival after IHIPEC was better compared with a matched group of patients (n = 16) receiving SCO (24.6 vs. 7.9 months; p = 0.005), and similar to those (n = 7) who underwent CRS + HIPEC (24.6 vs. 16.5 months; p = 0.62).

CONCLUSIONS

IHIPEC in combination with systemic chemotherapy is tolerable, safe, and may be associated with encouraging survival outcomes compared with SCO in selected patients with high-grade, high-burden AEGA PM.

Personalized viral-based prime/boost immunotherapy targeting patient-specific or shared neoantigens: Immunogenicity, safety, and efficacy results from two ongoing phase I studies

3137

Background: Neoantigens are key targets of a tumor-specific immune response and CD8 T cells targeting neoantigens drive clinical benefit in patients (pts) treated with checkpoint inhibitors. Methods: Two Phase I studies are being conducted to assess the safety, immunogenicity, and early clinical activity of a viral-based neoantigen-targeting prime/boost immunotherapy aimed at maximizing the CD8 T cell response. Both studies use a chimpanzee adenovirus prime followed by increasing doses of repeat boosts with a self-amplifying mRNA in combination with IV nivolumab +/- SC ipilimumab. In the first study, GO-004, patient-specific neoantigens are predicted using Gritstone's EDGE model and incorporated into both prime/boost vectors. In GO-005, shared neoantigens derived from common driver mutations (including several from KRAS) are encoded in off-the-shelf prime/boost vectors. Results: To date, 12 pts have been treated: 6 pts with GEA, NSCLC, or MSS-CRC (GO-004) and 6 pts with NSCLC, MSS-CRC, or PDA (GO-005) with all pts receiving IV nivolumab and 5 pts also receiving SC ipilimumab. Nine pts continue to receive study treatment. No DLTs have been observed. Treatment-related AEs are reversible and include Grade 1/2 fever (7/12), injection site reactions (4/12), fatigue (3/12), diarrhea (2/12), hypotension (2/12), pruritus (2/12), skin reactions (2/12), anorexia (1/12), dyspnea (1/12), hyponatremia (1/12), infusion-related reactions (1/12), myalgia (1/12), and asymptomatic Grade 3 CK elevation (1/12). At the time of analysis, 8 of 12 pts with ≥ 1 radiographic assessment have a best response of stable disease (SD) (3) and progressive disease (PD) (4), and one pt with no evaluable disease at baseline continues on study > 8 months. In GO-005, 1 pt with SD has a 20% reduction in tumor dimensions that correlates with a decrease in ctDNA. In 4 pts in GO-004 analyzed to date, all pts showed substantial neoantigen-specific CD8 T cell responses to multiple neoantigens after priming which increase further in 2 of 3 pts analyzed after subsequent boosts. In GO-005, 1 of 3 pts showed a robust KRAS G12C-specific CD8 T cell response. Induced T cells express IFNg and granzyme B, consistent with an effector response. Conclusions: Taken together, these early data support the tolerability of a viral-based prime/boost immunotherapy, demonstrate marked immunogenicity, and are consistent with potential clinical activity. Additional pts and data at higher dose levels will be presented. Clinical trial information: NCT03639714, NCT03953235 .

Response rates in metastatic neuroendocrine tumors receiving peptide receptor radionuclide therapy and implications for future treatment strategies

BACKGROUND

Peptide receptor radionuclide therapy is a targeted therapy used to treat unresectable somatostatin receptor-positive neuroendocrine tumors. The objective of this study was to evaluate response rates among neuroendocrine tumors of different primaries and identify factors relevant to future treatment strategies.

METHODS

We retrospectively reviewed patients who received peptide receptor radionuclide therapy for neuroendocrine tumors from 2018 to 2019 at our institution. Patients were assessed with computed tomography/magnetic resonance imaging and ⁶⁸Ga-DOTATATE-positron emission tomography before and after 2 or 4 cycles of peptide receptor radionuclide therapy. Tumor response was evaluated by RECIST 1.1. Statistics included multinomial logistic regression models and Fisher exact test.

RESULTS

Twenty-seven patients underwent 92 cycles of peptide receptor radionuclide therapy: pancreas (n = 11), small bowel (n = 7), and other (n = 9) neuroendocrine tumors. Overall, 30% (8 of 27) had partial response, 59% (16 of 27) stable disease, and 11% (3 of 27) progressed. Pancreatic neuroendocrine tumors responded differently from small bowel neuroendocrine tumors regardless of cycle number (P = .01). The majority of pancreatic neuroendocrine tumors (6 of 11) had partial response to peptide receptor radionuclide therapy, while all small bowel neuroendocrine tumors had stable disease. Pancreatic neuroendocrine tumors stable after 2 cycles were more likely to respond to additional cycles versus other neuroendocrine tumors (probability: 60% vs 11%).

CONCLUSION

Patients with unresectable advanced or metastatic pancreatic neuroendocrine tumors may benefit from a full course of peptide receptor radionuclide therapy, whereas other neuroendocrine tumors appear less likely to respond. Large prospective studies are needed to confirm these findings.

Personalized antibodies for gastroesophageal adenocarcinoma (PANGEA): Secondary and final primary efficacy analyses

4561

Background: Targeted therapies (tx) have had limited benefit in advanced (aGEA) due to baseline spatial (primary vs metastatic tumor PT/MT) & temporal molecular heterogeneity (BMH/TMH). We previously reported PANGEA methods & results: 35% BMH rate & 10 OS results achieving 1yr OS of 66% & mOS of 16.4 months (m) using the personalized tx strategy (Catenacci et al. GI ASCO 2020 Abstr356). Here we will report the TMH rates at progressive disease points (PD1 & PD2), ORR/PFS/DCR in each of 3 tx lines, time to strategy failure (TTF), & updated OS/safety. Methods: PANGEA enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) tx lines (L). Baseline tissue biomarker profiling (BP) was mandated on PT/MT & PD1/PD2, & ctDNA analysis throughout. After initiating 1L cx & upon learning MT BP results, antibody (AN) was added by a predefined prioritized tx algorithm incorporating tissue & blood BP (Table). At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per tx algorithm. The same was done at PD2. The 10 endpoint was 1yr OS; enrolling 68 pts provided 80% power to detect a 63% 1yr OS compared to historical 50% 1yr OS (HR 0.67), using a 1-sided test (0.10 alpha). Results: 80 pts were enrolled, & 68 tx’d per protocol. At data cut-off 2/1/20, 15 pts were still on trial with only 2 of these pts on tx <12m (8 pts in 1L, 5 in 2L, 2 in 3L). All 68 pts had at least 1 dose of 1L tx, 87% 2L tx, & 36% 3L tx. AN assigned by the tx algorithm at 1L, OS, TTF, & ORR1/PFS1/DCR1 of 1L tx are shown in Table; 2L & 3L ORR/DCR outcomes will be shown. The 3yr & 4yr OS rates were 12% & 8%. TMH leading to molecular subgroup change by tx algorithm was 51% after 1L & 36% after 2L; details & results by subgroup will be provided. Any grade >3 non-heme tox thru all 3 tx lines was seen in 25% of pts. Conclusions: PANGEA showed superior 10 & 20 endpoint efficacy, even when excluding HER2- pts, compared to historical outcomes. Clinical trial information: NCT02213289 . [Table: see text]

Evaluation of the Association of Perioperative UGT1A1 Genotype-Dosed gFOLFIRINOX With Margin-Negative Resection Rates and Pathologic Response Grades Among Patients With Locally Advanced Gastroesophageal Adenocarcinoma: A Phase 2 Clinical Trial

IMPORTANCE

Patients with locally advanced gastroesophageal adenocarcinoma (ie, stage ≥T3 and/or node positive) have high rates of recurrence despite surgery and adjunctive perioperative therapies, which also have high toxicity profiles. Evaluation of pharmacogenomically dosed perioperative gFOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and UGT1A1 genotype-directed irinotecan) to optimize efficacy while limiting toxic effects may have value.

OBJECTIVE

To evaluate the coprimary end points of margin-negative (R0) resection rates and pathologic response grades (PRGs) of gFOLFIRINOX therapy among patients with locally advanced gastroesophageal adenocarcinoma.

DESIGN, SETTING, AND PARTICIPANTS

This single-group phase 2 trial, conducted at 2 academic medical centers from February 2014 to March 2019, enrolled 36 evaluable patients with locally advanced adenocarcinoma of the esophagus, gastroesophageal junction, and gastric body. Data analysis was conducted in May 2019.

INTERVENTIONS

Patients received biweekly gFOLFIRINOX (fluorouracil, 2400 mg/m2 over 46 hours; oxaliplatin, 85 mg/m2; irinotecan, 180 mg/m2 for UGT1A1 genotype 6/6, 135 mg/m2 for UGT1A1 genotype 6/7, or 90 mg/m2 for UGT1A1 genotype 7/7; and prophylactic peg-filgastrim, 6 mg) for 4 cycles before and after surgery. Patients with tumors positive for ERBB2 also received trastuzumab (6-mg/kg loading dose, then 4 mg/kg).

MAIN OUTCOMES AND MEASURES

Margin-negative resection rate and PRG.

RESULTS

A total of 36 evaluable patients (27 [78%] men; median [range] age, 66 [27-85] years; 10 [28%] with gastric body cancer; 24 [67%] with intestinal-type tumors; 6 [17%] with ERBB2-positive tumors; 19 [53%] with UGT1A1 genotype 6/6; 16 [44%] with genotype 6/7; and 1 [3%] with genotype 7/7) were enrolled. Of these, 35 (97%) underwent surgery; 1 patient (3%) died after completing neoadjuvant chemotherapy while awaiting surgery. Overall, R0 resection was achieved in 33 of 36 patients (92%); 2 patients (6%) with linitis plastica achieved R1 resection. Pathologic response grades 1, 2, and 3 occurred in 13 patients (36%), 9 patients (25%), and 14 patients (39%), respectively, and PRG 1 was observed in 11 of 24 intestinal-type tumors (46%). Median disease-free survival was 30.1 months (95% CI, 15.0 months to not reached), and median overall survival was not reached (95% CI, 8.3 months to not reached). There were no differences in outcomes by UGT1A1 genotype group. A total of 38 patients, including 2 (5%) with antral tumors, were evaluable for toxic effects. Grade 3 or higher adverse events occurring in 5% or more of patients during the perioperative cycles included diarrhea (7 patients [18%]; 3 of 19 patients [16%] with genotype 6/6; 2 of 16 patients [13%] with genotype 6/7; 2 of 3 patients [67%] with genotype 7/7), anemia (2 patients [5%]), vomiting (2 patients [5%]), and nausea (2 patients [5%]).

CONCLUSIONS AND RELEVANCE

In this study, perioperative pharmacogenomically dosed gFOLFIRINOX was feasible, providing downstaging with PRG 1 in more than one-third of patients and an R0 resection rate in 92% of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02366819.

Personalized ANtibodies for GastroEsophageal Adenocarcinoma (PANGEA): Primary efficacy analysis of the phase II platform trial (NCT02213289)

356

Background: 1-yr OS is ~40% for HER2- & ~55% for HER2+ advanced (aGEA). Targeted therapies (tx) have had limited benefit due to molecular heterogeneity. Methods: This phase 2a study of a personalized tx strategy (PTS) enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) lines: first line (1L) 5FU + oxaliplatin, 2L 5FU + irinotecan & 3L 5FU + docetaxel. Baseline biomarker profiling (BP) was mandated on primary & metastatic tumors (PT/MT) & progressive disease points (PD1, PD2). Assigned antibody (AN) was added to cx by a predefined prioritized tx algorithm (PTA) (Table) based on the MT BP. At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per PTA. The same was done at PD2. If AN was unavailable (MET/FGFR2), these pts were tx’d with cx alone (not ITT). The 10 endpt was 1-yr OS of the PTS. Assuming historical 50% 1-yr OS for all aGEA pts, 68 pts tx’d per protocol PTS provided 80% power to detect an HR=0.67, corresponding to a 1-yr OS rate of 63% (under exponential survival), using a 1-sided test at the 0.10 alpha level. 20 endpts: safety, feasibility, PT/MT BP discordance at baseline & over tx line, & OS/PFS/ORR by tx line & BP group. Results: Between 6/2015-5/2019, 80 consecutive pts enrolled at 3 sites: ECOG PS 0-2 40/33/7; Male 80%; median age 60, range 28-81, peritoneal disease 36%. AN assigned by PTA at 1L & 1-yr OS are shown (Table). PT/MT discordance was 37%. Of 68 pts treated by PTS ITT, the 1-yr OS was 69.4% (p<0.001). The mOS was 16.4m [95%CI 13.8-20.8]. Any grade >3 tox thru all 3 tx lines was seen in 32% of pts. 20 analyses will be presented. Conclusions: PANGEA was feasible & met its 10 efficacy objective with observed 1-yr OS of 69.4%, meriting a randomized study. Clinical trial information: NCT02213289 . U.S. National Institutes of Health.[Table: see text]

Cytoreductive surgery in selected patients with metastatic gastric cancer treated with systemic chemotherapy

409

Background: Cytoreductive surgery (CRS – gastrectomy combined with metastasectomy) for non-palliative indications is controversial for patients with metastatic gastric adenocarcinoma (MGA). We hypothesized that CRS in addition to systemic chemotherapy is associated with an improved survival when compared to patients with MGA receiving chemotherapy alone. Methods: Patients with MGA who received systemic chemotherapy between 2004-2016 were identified using the National Cancer Database (NCDB). Nearest neighbor 1:1 propensity score matching of demographic, tumor-related and treatment-related factors was used to create comparable groups. Overall survival (OS) was compared between subgroups using Kaplan-Meier analyses. Immortal bias analysis was performed among those that survived at least 90 days. Results: We identified 29,728 chemotherapy-treated patients who were divided into 4 subgroups: No surgery (NS, n = 25,690), metastasectomy alone (n = 1170), gastrectomy alone (n = 2248) and CRS (n = 620) with a median OS of 8.6, 10.9, 14.8 and 16.3 months, respectively (p < 0.001). Compared to patients who underwent no surgery, patients who underwent CRS were younger (58.9±13.4 vs. 62.0±13.1 years), had lower proportion of disease involving multiple sites (5.0% vs. 26.2%), and were more likely to have clinically occult disease (cM0 58.9% vs. 7.3%) - all p < 0.001. OS for propensity matched patients who underwent CRS (n = 490) was longer than NS (16.3 vs. 8.8 months, p < 0.001), including those with clinical M1 stage (n = 203) in both unmatched and propensity matched (median OS 19.7 vs. 8.6 months, p < 0.001) cohorts. On Cox regression model using the matched data, the hazard ratio for CRS vs. NS was 0.80 (95%CI 0.76-0.84). In the immortal matched cohort, the corresponding median OS was 16.7 vs. 9.7 months, p < 0.001. Conclusions: CRS in addition to systemic chemotherapy may be associated with an OS benefit in a selected group of patients with metastatic gastric adenocarcinoma. Suboptimal matching for tumor burden is our major limitation. In contrast to studies that focus on gastrectomy alone in the setting of MGA, this study highlights the role of CRS among patients receiving systemic chemotherapy.

Perioperative (P) UGT1A1 genotype guided irinotecan (iri) dosing ‘gFOLFIRINOX’ for gastroesophageal adenocarcinoma (GEA)

4050

Background: Complete resection (R0) and pathologic response grade (PRG) correlate with long-term GEA outcome. FOLFIRINOX demonstrated efficacy in advanced GEA; gFOLFIRINOX improved tolerability. We evaluated R0, PRG and tolerability in this pilot P study. Methods: Gastric body (GB) + esophagogastric (EGJ) GEA patients (pts) with ≥T3Nx or TxN+ were enrolled & treated with 4 pre + 4 postoperative biweekly cycles of gFOLFIRINOX (5-FU 2400mg/m2 over 46 hrs; oxaliplatin 85mg/m2; iri: 180mg/m2 for UGT1A1 genotype 6/6, 135mg/m2 for 6/7, 90mg/m2 for 7/7) (+ trastuzumab (T) 6mg/kg then 4mg/kg for HER2+) with prophylactic peg-filgastrim. 1°endpoint R0 resection required 36 pts to assess for a 90% R0 rate (intention to treat (ITT)) with 90% power + 0.05 alpha; ≥30/36 R0 considered positive. Co-1°endpoint was PRG (Becker); 36 pts provided 85% power with 0.05 alpha for a complete (pCR G1a) rate of 16%. 2°endpoints were safety/toxicity, PET response, & R0/PRG by tumor site, histologic subtype, HER2 status, & UGT1A1 genotype. We report efficacy and toxicity data from the neoadjuvant (Neo) portion of the study; postop data & survival outcomes will be presented at the meeting. Results: 4 sites enrolled 36 ITT pts between 2/2014-8/2018; 75% male, median age 66 (range 27-85). All pts completed all 4 cycles of Neo therapy: 10% had any dose reduction of iri (16%/0%/25% by genotype 6/6, 6/7, 7/7); any G3+ toxicity occurred in 35% of pts (32% 6/6, 29% 6/7, 75% 7/7). G3+ toxicity in ≥5% of pts: diarrhea (17.5%; 6/6 21%, 6/7 11%, 7/7 25%), anemia (5%), vomiting (5%). Efficacy is shown in the Table. Of pts going to surgery, both R1 resections were GB linitus. PRG1(a+b) was achieved in 36% of ITT pts, 46% of intestinal type histology. Conclusions: Neo gFOLFIRINOX was tolerable with surrogate efficacy comparable to FLOT. Clinical trial information: NCT02366819. [Table: see text]

Deep sequencing of small RNA libraries reveals dynamic expression patterns of microRNAs in multiple developmental stages of Bactrocera dorsalis

In eukaryotes, microRNAs (miRNAs) are small, conserved, noncoding RNAs that have emerged as critical regulators of gene expression. The oriental fruit fly Bactrocera dorsalis is one of the most economically important fruit fly pests in East Asia and the Pacific. Although transcriptome analyses have greatly enriched our knowledge of its structural genes, little is known about post-transcriptional regulation by miRNAs in this dipteran species. In this study, small RNA libraries corresponding to four B. dorsalis developmental stages (eggs, larvae, pupae and adults) were constructed and sequenced. Approximately 30.7 million reads of 18-30 nucleotides were obtained, with 123 known miRNAs and 60 novel miRNAs identified amongst these libraries. More than half of the miRNAs were stage-specific during the four developmental stages. A set of miRNAs was found to be up- or down-regulated during development by comparison of their reads at different developmental stages. Moreover, a small part of miRNAs owned both miR-#-3p and miR-#-5p types, with enormously variable miR-#-3p/miR-#-5p ratios in the same library and amongst different developmental stages for each miRNA. Taking these findings together, the current study has uncovered a number of miRNAs and provided insights into their possible involvement in developmental regulation by expression profiling of miRNAs. Further analyses of the expression and function of these miRNAs could increase our understanding of regulatory networks in this insect and lead to novel approaches for its control.

Phase I pharmacokinetic and pharmacodynamic study of SJG-136, a novel DNA sequence selective minor groove cross-linking agent, in advanced solid tumors

PURPOSE

This phase I study assessed the maximum tolerated dose (MTD), safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of SJG-136, a sequence-specific DNA cross-linking agent, in patients with advanced cancer.

EXPERIMENTAL DESIGN

In schedule A, seven patients received escalating doses of SJG-136 (6, 12, 24, and 48 μg/m(2)) daily for 5 of 21 days. Blood samples were collected for PK analysis on days 1 and 5 of cycle 1. In schedule B, SJG-136 was given daily for 3 of 21 days (N = 17; doses 20, 25, 30, and 35 μg/m(2)). Blood samples were collected on days 1 and 3 of cycles 1 and 2 for PK and PD analysis. Patients in schedule B received dexamethasone and early diuretic care.

RESULTS

Schedule A-dose-limiting toxicities included grade 3 edema, dyspnea, fatigue, and delayed liver toxicity (grade 3-4). PK analysis revealed dose-dependent increases in AUC and C(max). Substantial changes in volume of distribution at steady-state occurred after repeated dosing in some patients prior to the onset of edema. Schedule B-the same toxicities were manageable with steroid premedication and diuretic support. No significant myelosuppression occurred on either schedule. DNA interstrand cross-links correlated with systemic exposure of SJG-136 following the second dose in cycle 1 and were still detectable immediately before cycle 2.

CONCLUSIONS

The MTD of SJG-136 in this study was 30 μg/m(2) administered on a daily 3× basis with no myelosuppression effects. Coupled with supportive management, SJG-136 is now advancing to a phase II trial in ovarian cancer.

Interstitial-mediated diffusion in germanium under proton irradiation

We report experiments on the impact of 2.5 MeV proton irradiation on self-diffusion and dopant diffusion in germanium (Ge). Self-diffusion under irradiation reveals an unusual depth independent broadening of the Ge isotope multilayer structure. This behavior and the observed enhanced diffusion of B and retarded diffusion of P demonstrates that an interstitial-mediated diffusion process dominates in Ge under irradiation. This fundamental finding opens up unique ways to suppress vacancy-mediated diffusion in Ge and to solve the donor deactivation problem that hinders the fabrication of Ge-based nanoelectronic devices.

Theory of nanocluster size distributions from ion beam synthesis

Ion beam synthesis of nanoclusters is studied via both kinetic Monte Carlo simulations and the self-consistent mean-field solution to a set of coupled rate equations. Both approaches predict the existence of a steady-state shape for the cluster-size distribution that depends only on a characteristic length determined by the effective diffusion coefficient, the ion solubility, and the volumetric ion flux. The average cluster size in the steady-state regime is determined by the implanted species or matrix interface energy.

Expression of sex-determining genes in human sebaceous glands and their possible role in the pathogenesis of acne

BACKGROUND

The human skin, especially the sebaceous gland, is a steroidogenic organ similar to the gonads and adrenal cortex, possessing all the enzymes required for steroid sex-hormone synthesis and metabolism. Factors regulating cutaneous steroidogenesis associated with disease status remain largely unknown.

OBJECTIVE

We hypothesized that transcription factors involved in sex formation and regulation of steroidogenesis in the classical steroidogenic organs are also expressed in the sebaceous glands. Their possible role in the pathogenesis of acne were investigated.

METHODS

We used reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization and Western blotting to analyse the expression of SF-1, WT-1, SRY, SOX-9 and DAX-1 mRNAs and their proteins in cultured human sebocytes and the facial skin of acne patients.

RESULTS

The in situ hybridization study showed SOX-9 mRNA mainly localized in basal keratinocytes, the basal layer of the sebaceous glands and eccrine glands. Immortalized human sebaceous gland cells (SZ95) expressed mRNA for SOX-9, WT-1 and DAX-1 but not for SF-1 or SRY. The expression of DAX-1 protein was slightly inhibited by 10(-6) m oestradiol (E2) at 6 h but enhanced by 10(-6) m dihydrotestosterone (DHT) at 48 h. The facial expression of SOX-9 seemed to be higher in the acne-prone male patients, while DAX-1 was stronger in subjects without acne, although both were statistically insignificant.

CONCLUSION

Our findings confirm the expression of some sex-determining genes in human sebaceous glands. Further studies on a larger patient population including the normal controls are needed to elucidate the functional significance of these transcription factors in the pathogenesis of acne.

Large melting-point hysteresis of Ge nanocrystals embedded in SiO2

The melting behavior of Ge nanocrystals embedded within SiO2 is evaluated using in situ transmission electron microscopy. The observed melting-point hysteresis is large (+/-17%) and nearly symmetric about the bulk melting point. This hysteresis is modeled successfully using classical nucleation theory without the need to invoke epitaxy.

Dynamics of inherent structure in supercooled liquids near kinetic glass transition

We present a description of the dynamics of a supercooled binary Lennard-Jones liquid in term of the potential landscape of the system. The slowing down of the dynamics in supercooled liquids near the kinetic glass transition is related to the existence of basins in the potential landscape. The inherent structures that are the local potential minima in the configuration space obtained by a quench process are employed to represent the configurations of the basins. We present time correlation functions of the inherent structure, both the self and the coherent part, as a function of wave vector. We also calculated the mean-square displacement, and the non-Gaussian parameter of the van Hove self-correlation function. Compared with the dynamics of original configurations, the short-time relaxation has almost been eliminated by the quench process. However, the long-time alpha relaxations remain essentially the same. We conclude that the long-time alpha relaxation is the result of cross-basin transition in the potential landscape in the configuration space.

Prothymosin alpha enhances protective immune responses induced by oral DNA vaccination against pseudorabies delivered by Salmonella choleraesuis

Previously, we showed that vaccination with the glycoprotein D (gD) gene of pseudorabies virus (PrV) delivered by Escherichia coli induced protective immune responses. In this study, we report that oral DNA vaccination with attenuated Salmonella choleraesuis carrying the PrV gD gene conferred protective immunity in mice against PrV. Moreover, co-delivery of the prothymosin alpha gene carried by S. choleraesuis enhanced the vaccine efficacy. Our results thus demonstrate for the first time, to our knowledge, the effectiveness of oral DNA vaccination using S. choleraesuis as a delivery vehicle and the potential usefulness of prothymosin alpha as a DNA vaccine adjuvant.

[QTLs and epistasis underlying rice (Oryza sativa L.) panicle length in different genetic background and environments]

A double haploid (DH) population and a recombinant inbred (RI) population derived from a cross between a japonica male parent Azucena and indica female parents, IR64 and IR1552 respectively, were used in both field and pot experiments for detecting QTLs and epistasis for rice panicle length in different genetic background and different environments. Panicle length (PL) was measured at maturity. QTLs for PL were detected using single marker analysis and interval mapping. Epistasis effects on the trait were also analyzed. Nine QTLs were detected in DH population, including 5 QTLs detected from field experiment and 4 from pot experiment, among them 3 QTLs mapped on chromosomes 1 and 4 were identified in both field and pot experiments. No significant epistasis effect was detected for PL. Four QTLs were detected in RI population, among them 2 from field condition and 2 from pot experiment. 6 pairs of epistasis loci were detected in RI population. One QTL mapped on chromosome 4 and two pairs of epistatic loci were detected in both field and pot experiments. One QTL on chromosome four was identified in both populations, and one marker locus RG323 on chromosome one was involved in additive effect in DH population, but epistasis effects in RI population.

Collective dynamics in fully hydrated phospholipid bilayers studied by inelastic x-ray scattering

The short wavelength density fluctuation of DLPC (dilaurylphosphatidylcholine) bilayers close to full hydration has been studied by the inelastic x-ray scattering technique below and above the main transition temperature. The analysis based on a generalized three effective eigenmode theory allows us to construct the dispersion relation of the high frequency sound mode for the first time. The marked softening of the excitation near k = 14 nm(-1), corresponding to the lipid chain-chain correlation peak in the structure factor, in the L(alpha) phase implies prevalent occurrences of short-wavelength in-plane motions of lipid chains that might be of importance for transportation of small molecules across membranes.

Analysis of inelastic x-ray scattering spectra of low-temperature water

We analyze a set of high-resolution inelastic x-ray scattering (IXS) spectra from H2O measured at T=259, 273, and 294 K using two different phenomenological models. Model I, called the "dynamic cage model," combines the short time in-cage dynamics described by a generalized Enskog kinetic theory with a long-time cage relaxation dynamics described by an alpha relaxation. This model is appropriate for supercooled water where the cage effect is dominant and the existence of an alpha relaxation is evident from molecular-dynamics (MD) simulation data of extended simple point charge (SPC/E) model water. Model II is essentially a generalized hydrodynamic theory called the "three effective eigenmode theory" by de Schepper et al. 11. This model is appropriate for normal liquid water where the cage effect is less prominent and there is no evidence of the alpha relaxation from the MD data. We use the model I to analyze IXS data at T=259 K (supercooled water). We successfully extract the Debye-Waller factor, the cage relaxation time from the long-time dynamics, and the dispersion relation of high-frequency sound from the short time dynamics. We then use the model II to analyze IXS data at all three temperatures, from which we are able to extract the relaxation rate of the central mode and the damping of the sound mode as well as the dispersion relation for the high-frequency sound. It turns out that the dispersion relations extracted from the two models at their respective temperatures agree with each other giving the high-frequency sound speed of 2900+/-300 m/s. This is to be compared with a slightly higher value reported previously, 3200+/-320 m/s, by analyzing similar IXS data with a phenomenological-damped harmonic oscillator model 22. This latter model has traditionally been used exclusively for the analysis of inelastic scattering spectra of water. The k-dependent sound damping and central mode relaxation rate extracted from our model analyses are compared with the known values in the hydrodynamic limit.

Model for dynamics in supercooled water

We propose a phenomenological model for the intermediate scattering function (ISF) associated with density fluctuation in low temperature water. The motivation is twofold: to extract various physical parameters associated with the ISF computed from extended simple-point-charge model water at supercooled temperatures, and to apply this model to analyze high resolution inelastic x-ray scattering data of water in the future. The ISF of the center of mass of low temperature water computed from 10 M-step molecular dynamics (MD) data shows clearly time-separated two-step relaxation with a well-defined plateau in-between. We interpret this result as due to the formation of a stable hydrogen-bonded, tetrahedrally coordinated cage around a typical molecule in low temperature water. We thus model the long-time cage relaxation by the well-known Kohlrausch form exp[-(t/tau)(beta)] with an amplitude factor which is a k-dependent Debye-Waller factor A(k), and treat the short-time relaxation as due to molecular collisional motions within the cage. The latter motions can be described by the generalized Enskog equation, taking into account the confinement effect of the cage. We shall show that the effect of the confinement changes the collisional dynamics by modifying certain input parameters in the kinetic theory by a factor [1-A(k)](1/2). We solve the generalized Enskog equation approximately but analytically by a Q-dependent triple relaxation time kinetic model. This kinetic model was previously shown to account for the large k behavior of Rayleigh-Brillouin scattering from moderately dense, simple fluids. We find that our model fits well with the MD generated collective as well as single-particle ISFs. For the short-time collisional dynamics, we fix values of the hard sphere diameter sigma and pair correlation function at contact g(sigma), without introducing any adjustable parameters. The calculated ISFs reproduce the correct Brillouin peak frequencies at low k values. From the long-time dynamics, we deduce values of the Debye-Waller factor A(k), the Kohlrausch exponent beta(k), and the cage relaxation time tau(k).

SH3 domain of Bruton's tyrosine kinase can bind to proline-rich peptides of TH domain of the kinase and p120cbl

X-linked agammaglobulinemia (XLA), an inherited disease, is caused by mutations in the Bruton's tyrosine kinase (BTK). The absence of functional BTK leads to failure of B-cell differentiation; this incapacitates antibody production in XLA patients, who suffer from recurrent, sometimes lethal, bacterial infections. BTK plays an important role in B-cell development; it interacts with several proteins in the context of signal transduction. Point mutation in the BTK gene that leads to deletion of C-terminal 14 aa residues of BTK SH3 domain was found in a patient family. To understand the role of BTK, we studied binding of BTK SH3 domain (aa 216-273, 58 residues) and truncated SH3 domain (216-259, 44 residues) with proline-rich peptides; the first peptide constitutes the SH3 domain of BTK, while the latter peptide lacks 14 amino acid residues of the C terminal. Proline-rich peptides selected from TH domain of BTK and p120cbl were studied. It is known that BTK TH domain binds to SH3 domains of various proteins. We found that BTK SH3 domain binds to peptides of BTK TH domain. This suggests that BTK SH3 and TH domains may associate in inter- or intramolecular fashion, which raises the possibility that the kinase may be regulating its own activity by restricting the availability of both its ligand-binding modules. We also found that truncated SH3 domain binds to BTK TH domain peptide less avidly than does normal SH3 domain. Also, we show that the SH3 and truncated SH3 domains bind to peptide of p120cbl, but the latter domain binds weakly. It is likely that the truncated SH3 domain fails to present to the ligand the crucial residues in the correct context, hence the weaker binding. These results delineate the importance of C-terminal in binding of SH3 domains and indicate also that improper folding and the altered binding behavior of mutant BTK SH3 domain likely leads to XLA.