Society for Immunotherapy of Cancer (SITC) recommendations on intratumoral immunotherapy clinical trials (IICT): from premalignant to metastatic disease

BACKGROUND

Intratumorally delivered immunotherapies have the potential to favorably alter the local tumor microenvironment and may stimulate systemic host immunity, offering an alternative or adjunct to other local and systemic treatments. Despite their potential, these therapies have had limited success in late-phase trials for advanced cancer resulting in few formal approvals. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to determine how to design clinical trials with the greatest chance of demonstrating the benefits of intratumoral immunotherapy for patients with cancers across all stages of pathogenesis.

METHODS

An Intratumoral Immunotherapy Clinical Trials Expert Panel composed of international key stakeholders from academia and industry was assembled. A multiple choice/free response survey was distributed to the panel, and the results of this survey were discussed during a half-day consensus meeting. Key discussion points are summarized in the following manuscript.

RESULTS

The panel determined unique clinical trial designs tailored to different stages of cancer development-from premalignant to unresectable/metastatic-that can maximize the chance of capturing the effect of intratumoral immunotherapies. Design elements discussed included study type, patient stratification and exclusion criteria, indications of randomization, study arm determination, endpoints, biological sample collection, and response assessment with biomarkers and imaging. Populations to prioritize for the study of intratumoral immunotherapy, including stage, type of cancer and line of treatment, were also discussed along with common barriers to the development of these local treatments.

CONCLUSIONS

The SITC Intratumoral Immunotherapy Clinical Trials Expert Panel has identified key considerations for the design and implementation of studies that have the greatest potential to capture the effect of intratumorally delivered immunotherapies. With more effective and standardized trial designs, the potential of intratumoral immunotherapy can be realized and lead to regulatory approvals that will extend the benefit of these local treatments to the patients who need them the most.

Cancer cell-derived type I interferons instruct tumor monocyte polarization

Monocytes are highly plastic immune cells that modulate antitumor immunity. Therefore, identifying factors that regulate tumor monocyte functions is critical for developing effective immunotherapies. Here, we determine that endogenous cancer cell-derived type I interferons (IFNs) control monocyte functional polarization. Guided by single-cell transcriptomic profiling of human and mouse tumors, we devise a strategy to distinguish and separate immunostimulatory from immunosuppressive tumor monocytes by surface CD88 and Sca-1 expression. Leveraging this approach, we show that cGAS-STING-regulated cancer cell-derived IFNs polarize immunostimulatory monocytes associated with anti-PD-1 immunotherapy response in mice. We also demonstrate that immunosuppressive monocytes convert into immunostimulatory monocytes upon cancer cell-intrinsic cGAS-STING activation. Consistently, we find that human cancer cells can produce type I IFNs that polarize monocytes, and our immunostimulatory monocyte gene signature is enriched in patient tumors that respond to anti-PD-1 immunotherapy. Our work exposes a role for cancer cell-derived IFNs in licensing monocyte functions that influence immunotherapy outcomes.

535 A phase I/II study of REGN7075 (EGFRxCD28 costimulatory bispecific antibody) in combination with cemiplimab (anti–PD-1) in patients with advanced solid tumors

Background

T-cell redirecting bispecific antibodies (bsAbs) are therapeutics that recognize two distinct antigens: a tumor-associated antigen on tumor cells to promote recruitment of T-cells to the tumor, and a receptor on T-cells to potentiate anti-tumor activity. REGN7075 is a human immunoglobulin G4-based costimulatory bsAb designed to bridge epidermal growth factor receptor (EGFR) positive tumor cells with CD28 positive T-cells and to provide amplified T-cell receptor-CD3 complex-mediated T-cell activation within the tumor, through the activation of CD28 co-stimulation. In genetically humanized immunocompetent mouse models, REGN7075 in combination with anti–PD-1 (antibody directed against programmed cell death-1 receptor) improved anti-tumor activity compared with either single agent alone.1

Methods

This is an open label, Phase I/II, first-in-human study evaluating the safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity of REGN7075 (EGFRxCD28) alone and in combination with cemiplimab in patients with advanced solid tumors (NCT04626635). Patients must have a protocol-defined advanced solid tumor, be ≥18 years of age (≥20 years in Japan), have an Eastern Cooperative Oncology Group performance status of 0 or 1, and be naïve to anti–PD-1/anti–PD-ligand(L)1.This study includes dose escalation (a 4+3 design modified from 3+3; Part 1) and expansion phases (Part 2). In Part 1, patients will receive a lead-in of REGN7075 monotherapy for 3 weeks followed by combination therapy with cemiplimab 350 mg every 3 weeks. Study therapies are administered until disease progression, intolerable adverse events, withdrawal of consent, or other stopping criterion is met. Once a recommended Phase 2 dose is determined in Part 1, four tumor-specific expansion cohorts will be opened: non-small cell lung cancer (PD-L1 ≥50%), triple-negative breast cancer, colorectal cancer (microsatellite stable), and cutaneous squamous cell carcinoma. Primary endpoints are safety and tolerability of REGN7075 alone or in combination with cemiplimab for Part 1, and objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1 for Part 2. This study is currently open to enrollment.

Trial Registration

ClinicalTrials.

gov identifier NCT04626635.

References

Waite JC, Wang B, Haber L, et al. Tumor-targeted CD28 bispecific antibodies enhance the antitumor efficacy of PD-1 immunotherapy. Sci Transl Med 2020;12:2325.

Ethics Approval

This study was conducted in accordance with the principles of the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines. The study protocol and all amendments were approved by the institutional review board/ethics committee at each participating study site.

Consent

All patients provided written informed consent.

547 CERPASS: A randomized, controlled, open-label, phase 2 study of cemiplimab ± RP1 in patients with advanced cutaneous squamous cell carcinoma

Background

The prognosis for advanced and metastatic cutaneous squamous cell carcinoma (CSCC) remains poor for many patients with the disease despite approval of the anti-PD1 antibodies cemiplimab and pembrolizumab.1 2 RP1 is an oncolytic virus (HSV-1) that expresses a fusogenic glycoprotein (GALV-GP R-) and granulocyte macrophage colony stimulating factor (GM-CSF). In preclinical studies, RP1 induced immunogenic tumor cell death and provided potent systemic anti-tumor activity, which is further improved by combining anti-PD-1 therapy.3 Preliminary results from IGNYTE, a phase I/II clinical study of RP1 in combination with nivolumab showed a high rate of deep and durable responses in patients (pts) with CSCC.4 The objective of this trial is to evaluate the safety and efficacy of cemiplimab + RP1 versus cemiplimab alone in advanced CSCC.

Methods

This global, multicenter, randomized phase 2 study is enrolling pts with metastatic or unresectable, locally advanced CSCC who are not candidates for/refuse surgery and/or radiotherapy. Key eligibility criteria include no prior treatment with anti-PD1/PD-L1 antibodies or oncolytic viruses. The clinical trial will enroll approximately 180 pts from centers in the EU, Australia, Canada and USA. Pts will be randomized in a 2:1 ratio favoring the RP1 + cemiplimab arm. Pts will receive 350 mg of cemiplimab intravenously (IV) Q3W for up to 108 weeks. In the RP1 + cemiplimab arm, RP1 will be injected intratumorally at a starting RP1 dose of 1 × 10^6 plaque forming units (PFU)/mL alone, followed by up to 7 doses of RP1 at 1 × 10^7 PFU/mL Q3W together with cemiplimab. Pts in the combination arm may receive up to 8 additional RP1 doses. No crossover will be allowed. Pts will be stratified by disease status and prior systemic therapy. Tumor assessments will be performed every 9 weeks. Primary endpoints are overall response rate and complete response rate by blinded independent review. Secondary endpoints include safety, progression free survival, duration of response and overall survival. Exploratory endpoints include viral shedding and biodistribution, and immune biomarker analyses. This trial is currently enrolling pts.

Trial Registration

NCT04050436

References

Migden MR, Rischin D, Schmults CD, Guminski A, Hauschild A, Lewis KD, Chung CH, Hernandez-Aya L, Lim AM, Chang ALS, Rabinowits G, Thai AA, Dunn LA, Hughes BGM, Khushalani NI, Modi B, Schadendorf D, Gao B, Seebach F, Li S, Li J, Mathias M, Booth J, Mohan K, Stankevich E, Babiker HM, Brana I, Gil-Martin M, Homsi J, Johnson ML, Moreno V, Niu J, Owonikoko TK, Papadopoulos KP, Yancopoulos GD, Lowy I, Fury MG. PD-1 blockade with cemiplimab in advanced cutaneous squamous-cell carcinoma. N Engl J Med 2018;379(4):341–351.

Grob JJ, Gonzalez R, Basset-Seguin N, Vornicova O, Schachter J, Joshi A, Meyer N, Grange F, Piulats JM, Bauman JR, Zhang P, Gumuscu B, Swaby RF, Hughes BGM. Pembrolizumab monotherapy for recurrent or metastatic cutaneous squamous cell carcinoma: a single-arm phase II trial (KEYNOTE-629). J Clin Oncol 2020;38(25):2916–2925.

Thomas S, Kuncheria L, Roulstone V, Kyula JN, Mansfield D, Bommareddy PK, Smith H, Kaufman HL, Harrington KJ, Coffin RS. Development of a new fusion-enhanced oncolytic immunotherapy platform based on herpes simplex virus type 1. J Immunother Cancer 2019;7(1):214.

Middleton M, Aroldi F, Sacco J, Milhem M, Curti B, VanderWalde A, Baum S, Samson A, Pavlick A, Chesney J, Niu J, Rhodes T, Bowles T, Conry R, Olsson-Brown A, Earl Laux D, Kaufman H, Bommareddy P, Deterding A, Samakoglu S, Coffin R, Harrington K. 422 An open-label, multicenter, phase 1/2 clinical trial of RP1, an enhanced potency oncolytic HSV, combined with nivolumab: updated results from the skin cancer cohorts. J Immunother Cancer 2020; 8 (3).

Ethics Approval

The study was approved by institutional review board or the local ethics committee at each site. Informed consent was obtained from patients before participating into the trial.

Phase I Trial of Cemiplimab, Radiotherapy, Cyclophosphamide, and Granulocyte Macrophage Colony-Stimulating Factor in Patients with Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

LESSONS LEARNED

Cemiplimab in combination with radiation therapy, cyclophosphamide, and granulocyte macrophage colony-stimulating factor did not demonstrate efficacy above what can be achieved with other PD-1 inhibitor monotherapies in patients with refractory and metastatic head and neck squamous cell carcinoma. The safety profile of cemiplimab combination therapy was consistent with previously reported safety profiles of cemiplimab monotherapy. No new safety signal was observed.

BACKGROUND

Refractory and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) generally does not respond to PD-1 inhibitor monotherapy. Cemiplimab is a human anti-PD-1 monoclonal antibody. An expansion cohort enrolled patients with R/M HNSCC in a phase I study combining cemiplimab plus radiation therapy (RT), cyclophosphamide, and granulocyte macrophage colony-stimulating factor (GM-CSF).

METHODS

Patients with R/M HNSCC refractory to at least first-line therapy and for whom palliative RT is clinically indicated received cemiplimab plus RT, cyclophosphamide, and GM-CSF. The co-primary objectives were the safety, tolerability, and efficacy of cemiplimab plus RT, cyclophosphamide, and GM-CSF in 15 patients with R/M HNSCC.

RESULTS

Fifteen patients were enrolled. Patients discontinued treatment due to progression of disease. The most common treatment-emergent adverse events (TEAEs) of any grade were fatigue (40.0%), constipation (26.7%), and asthenia, dyspnea, maculo-papular rash, and pneumonia (each 20%). The only grade ≥3 TEAE that occurred in two patients was pneumonia (13.3%). By investigator assessment, there was one partial response (6.7%); disease control rate was 40.0% (95% confidence interval [CI], 16.3-67.7; five patients with stable disease); seven patients had progressive disease, and two were not evaluable. Median progression-free survival by investigator assessment was 1.8 months (95% CI, 1.7-4.7).

CONCLUSION

The regimen demonstrated tolerability but not efficacy above that which can be achieved with anti-PD-1 inhibitor monotherapy for R/M HNSCC.

OncoTree: A Cancer Classification System for Precision Oncology

PURPOSE

Cancer classification is foundational for patient care and oncology research. Systems such as International Classification of Diseases for Oncology (ICD-O), Systematized Nomenclature of Medicine Clinical Terms (SNOMED-CT), and National Cancer Institute Thesaurus (NCIt) provide large sets of cancer classification terminologies but they lack a dynamic modernized cancer classification platform that addresses the fast-evolving needs in clinical reporting of genomic sequencing results and associated oncology research.

METHODS

To meet these needs, we have developed OncoTree, an open-source cancer classification system. It is maintained by a cross-institutional committee of oncologists, pathologists, scientists, and engineers, accessible via an open-source Web user interface and an application programming interface.

RESULTS

OncoTree currently includes 868 tumor types across 32 organ sites. OncoTree has been adopted as the tumor classification system for American Association for Cancer Research (AACR) Project Genomics Evidence Neoplasia Information Exchange (GENIE), a large genomic and clinical data-sharing consortium, and for clinical molecular testing efforts at Memorial Sloan Kettering Cancer Center and Dana-Farber Cancer Institute. It is also used by precision oncology tools such as OncoKB and cBioPortal for Cancer Genomics.

CONCLUSION

OncoTree is a dynamic and flexible community-driven cancer classification platform encompassing rare and common cancers that provides clinically relevant and appropriately granular cancer classification for clinical decision support systems and oncology research.

MET activation confers resistance to cetuximab, and prevents HER2 and HER3 upregulation in head and neck cancer

An understanding of the mechanisms underlying acquired resistance to cetuximab is urgently needed to improve cetuximab efficacy in patients with head and neck squamous cell carcinoma (HNSCC). Here, we present a clinical observation that MET pathway activation constitutes the mechanism of acquired resistance to cetuximab in a patient with HNSCC. Specifically, RNA sequencing and mass spectrometry analysis of cetuximab-sensitive (Cetux^Sen ) and cetuximab-resistant (Cetux^Res ) tumors indicated MET amplification and overexpression in the Cetux^Res tumor compared to the Cetux^Sen lesion. Stimulation of MET in HNSCC cell lines was sufficient to reactivate the MAPK pathway and to confer resistance to cetuximab in vitro and in vivo. In addition to the direct role of MET in reactivation of the MAPK pathway, MET stimulation abrogates the well-known cetuximab-induced compensatory feedback loop of HER2/HER3 expression. Mechanistically, we showed that the overexpression of HER2 and HER3 following cetuximab treatment is mediated by the ETS homologous transcription factor (EHF), and is suppressed by MET/MAPK pathway activation. Collectively, our findings indicate that evaluation of MET and HER2/HER3 in response to cetuximab in HNSCC patients can provide the rationale of successive line of treatment.

Anti-Hu-Associated Autoimmune Limbic Encephalitis in a Patient with PD-1 Inhibitor-Responsive Myxoid Chondrosarcoma

Autoimmune encephalitis is an uncommon complication of immune checkpoint inhibitor therapy. This article reports a case of fatal anti-Hu-associated autoimmune limbic encephalitis presenting within 8 weeks following anti-PD1 therapy in a patient with myxoid chondrosarcoma and pre-existing anti-Hu antibodies. Although tumor reduction occurred in response to PD-1 inhibitor therapy, the patient had a rapidly progressive decline in neurologic function despite initial stabilization with immunosuppression. Considering the increasing use of immune checkpoint inhibitors for the treatment of various malignancies, an increase in the occurrence of neurologic adverse events is likely, requiring prompt intervention and enhanced pharmacovigilance in malignancies associated with onconeuronal antibodies.

A nomogram to predict loco-regional control after re-irradiation for head and neck cancer

BACKGROUND AND PURPOSE

Loco-regionally recurrent head and neck cancer (HNC) in the setting of prior radiotherapy carries significant morbidity and mortality. The role of re-irradiation (re-RT) remains unclear due to toxicity. We determined prognostic factors for loco-regional control (LRC) and formulated a nomogram to help clinicians select re-RT candidates.

MATERIAL AND METHODS

From July 1996 to April 2011, 257 patients with recurrent HNC underwent fractionated re-RT. Median prior dose was 65 Gy and median time between RT was 32.4 months. One hundred fifteen patients (44%) had salvage surgery and 172 (67%) received concurrent chemotherapy. Median re-RT dose was 59.4 Gy and 201 (78%) patients received IMRT. Multivariate Cox proportional hazards were used to identify independent predictors of LRC and a nomogram for 2-year LRC was constructed.

RESULTS

Median follow-up was 32.6 months. Two-year LRC and overall survival (OS) were 47% and 43%, respectively. Recurrent stage (P=0.005), non-oral cavity subsite (P<0.001), absent organ dysfunction (P<0.001), salvage surgery (P<0.001), and dose >50 Gy (P=0.006) were independently associated with improved LRC. We generated a nomogram with concordance index of 0.68.

CONCLUSION

Re-RT can be curative, and our nomogram can help determine a priori which patients may benefit.

18F-FDG PET/CT metabolic tumor volume and total lesion glycolysis predict outcome in oropharyngeal squamous cell carcinoma

Treatment of oropharyngeal squamous cell carcinoma with chemoradiotherapy can now accomplish excellent locoregional disease control, but patient overall survival (OS) remains limited by development of distant metastases (DM). We investigated the prognostic value of staging (18)F-FDG PET/CT, beyond clinical risk factors, for predicting DM and OS in 176 patients after definitive chemoradiotherapy.

METHODS

The PET parameters maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were recorded. Univariate Cox regression was used to examine the prognostic value of these variables and clinical prognosticators for local treatment failure (LTF), OS, and DM. Multivariate analysis examined the effect of SUVmax, TLG, and MTV in the presence of other covariates. Kaplan-Meier curves were used to evaluate prognostic values of PET/CT parameters.

RESULTS

Primary tumors were distributed across all stages. Most patients underwent chemoradiotherapy only, and 11 also underwent tonsillectomy. On univariate analysis, primary tumor MTV was predictive of LTF (P = 0.005, hazard ratio [HR] = 2.4 for a doubling of MTV), DM and OS (P < 0.001 for both, HR = 1.9 and 1.8, respectively). The primary tumor TLG was associated with DM and OS (P < 0.001, HR = 1.6 and 1.7, respectively, for a doubling of TLG). The primary tumor SUVmax was associated with death (P = 0.029, HR = 1.1 for a 1-unit increase in standardized uptake value) but had no relationship with LTF or DM. In multivariate analysis, TLG and MTV remained associated with death after correcting for T stage (P = 0.0125 and 0.0324, respectively) whereas no relationship was seen between standardized uptake value and death after adjusting for T stage (P = 0.158).

CONCLUSION

Parameters capturing the volume of (18)F-FDG-positive disease (MTV or TLG) provide important prognostic information in oropharyngeal squamous cell carcinoma treated with chemoradiotherapy and should be considered for risk stratification in this disease.

Comparison of cisplatin (CDDP) and radiation (RT) to cetuximab (C) and RT for locally advanced head and neck cancer (LAHNC): A preliminary analysis

6042

Background: Both concurrent CDDP/RT and C/RT have been shown in randomized trials to yield superior disease control compared to RT alone in LAHNC, but no randomized trial has compared them. We evaluated our center's experience with these regimens. Methods: From 3/1/06 - 4/1/08, 175 patients were retrospectively identified who received definitive treatment for LAHNC with CDDP (planned total dose 100 mg/m2 Q3 weeks X 3) and RT (n = 125) or C (400 mg/m2 load; 250 mg/m2 weekly) and RT (n = 50). Patients who received prior RT, additional systemic therapy, and/or surgery to the primary site were excluded. C was given for the following reasons: auditory 30%, renal 4%, cardiac 2%, performance status 18%, patient choice 16%, neuropathy 4%, unknown 2%, and a combination of factors 24%. The median age: CDDP group 56, 6% >71; C group 66.5, 40% >71. Additional CDDP and C features: male sex, 86 v 78%; stage IV, 70 v 68%; and oropharynx, 78 v 70%. Median RT dose (70 Gy), RT length (46 days), and Karnofsky performance status (KPS) (90%) were the same; alcohol/tobacco use was similar. Results: At a median follow up of 18.7 months, with death without local failure (LF) as a competing risk, the 18 month LF incidence rate was 2.5% in the CDDP group and 43.3% in the C group (p < 0.0001), with the latest event occurring at 16.5 months. The 18 month disease-free survival (DFS) and overall survival (OS) rates were 85.7 v 40.9%, and 96.8 v 73.1%, in favor of CDDP (p < 0.0001 for both). Initially, 21 variables were assessed for significance, and when Cox proportional hazards model was used for multivariate analysis to address prognostic imbalances, treatment with CDDP still predicted for improved LF, DFS, and OS (p < 0.0001 for LF and DFS; p = 0.0017 for OS). For OS analysis, the concordance probability estimates were .67 for using drug choice alone and .80 for using drug choice, T stage, RT dose, and KPS. Conclusions: CDDP/RT and C/RT were used to treat somewhat different populations with LAHNC. The observed superiority of CDDP/RT compared to C/RT in LF, DFS, and OS may reflect patient selection issues. However, preliminary multivariate modeling suggests that CDDP/RT remains the preferred option for fit patients pending further analyses and prospective studies comparing these regimens.

[Table: see text]

Correlation of dynamic contrast enhanced magnetic resonance imaging (DCE MRI) with 18f-fluoromisonidazole positron emission and computed tomography (18F-FMISO PET/CT) in assessing tumor hypoxia in a series of head and neck cancer (HNC) patients with nodal metastases

6083

Background: 18F-FMISO PET/CT is a noninvasive hypoxia imaging modality. Hypoxia can develop within the tumor which typically corresponds to regions with poor blood perfusion. DCE-MRI can yield results on tumor perfusion. The present study compares hypoxic and perfusion status of HNC with nodal metastases using DCE-MRI and 18F-FMISO PET/CT imaging. Methods: 13 HNC (7 base of tongue, 5 tonsil, 1 larynx) patients with nodal metastases underwent both DCE-MRI and 18F-FMISO PET/CT scans prior to chemoradiotherapy. MRI was performed on a 1.5 Tesla GE Excite scanner. DCE-MRI studies were acquired using a fast multi-phase spoiled gradient echo sequence. Antecubital vein catheters delivered a bolus of 0.1 mmol/kg Gd-DTPA at 2 cc/s. For 18F-FMISO PET/CT,∼10.0 mCi of 18F-FMISO was administered IV and images were acquired ∼2 hours later. PET images were reconstructed; CT data were used for attenuation correction. Region of interests (ROIs) were manually drawn by a neuroradiologist. Quantitative DCE-MRI analyses were done using the 2-compartment Tofts model. The analyses calculated the pixel Ktrans(distribution rate constant), ve(extravascular-extra-cellular volume fraction), and kep(redistribution rate constant). 18F-FMISO PET/CT images were analyzed and the uptake by the tumor was scored as: no uptake (score 0); moderate-severe uptake (score 1). Semi-quantitative analysis included standardized uptake value (SUV) measurements. Statistical significance was calculated using a 2-sided Student's t-test, with p < 0.05. Results: A total of 17 nodes were analyzed. For the nodes that showed no hypoxia on PET imaging (n = 7), the mean (±SD) values were: 18F-MISO SUV (1.1 ± 03), Ktrans(0.33 ± 0.18), ve(0.53 ± 0.23), and kep(0.66 ± 0.25). For the nodes that showed moderate to severe 18F-MISO uptake (n = 10) the values were: 18F-FMISO SUV (2.8 ± 08), Ktrans(0.24 ± 0.07), ve(0.61 ± 0.13), and kep (0.43 ± 0.17). A significant lower kep for nodes with 18F-MISO uptake (p = 0.042). Conclusions: Preliminary result supports the hypothesis that the hypoxic nodes are poorly perfused nodes (lower kep values) versus nodes with no hypoxia.

No significant financial relationships to disclose.

PET monitoring of therapy response in head and neck squamous cell carcinoma

In the Western world, more than 90% of head and neck cancers are head and neck squamous cell carcinomas (HNSCCs). The most appropriate treatment approach for HNSCC varies with the disease stage and disease site in the head and neck. Concurrent chemoradiotherapy has become a widely used means for the definitive treatment of locoregionally advanced HNSCC. Although this multimodality treatment provides higher response rates than radiotherapy alone, the detection of residual viable tumor after the end of therapy remains an important issue and is one of the major applications of (18)F-FDG PET. Studies have shown that negative (18)F-FDG PET or PET/CT results after concurrent chemoradiotherapy have a high negative predictive value (>95%), whereas the positive predictive value is only about 50%. However, when applied properly, FDG PET/CT can exclude residual disease in most patients, particularly patients with residual enlarged lymph nodes who would otherwise undergo neck dissection. In contrast to other malignancies, data are limited on the utility of (18)F-FDG PET for monitoring the response to induction chemotherapy in HNSCC or for assessing treatment response early during the course of definitive chemoradiotherapy. The proliferation marker (18)F-3'-deoxy-3'fluorothymidine is currently under study for this purpose. Beyond standard chemotherapy, newer treatment regimens in HNSCC take advantage of our improved understanding of tumor biology. Two molecules important in the progression of HNSCC are the epidermal growth factor receptor and the vascular endothelial growth factor (VEGF) and its receptor VEGF-R. Drugs attacking these molecules are now under study for HNSCC. PET probes have been developed for imaging the presence of these molecules in HNSCC and their inhibition by specific drug interaction; the relevance of these probes for response assessment in HNSCC will be discussed. Hypoxia is a common phenomenon in HNSCC and renders cancers resistant to chemo- and radiotherapy. Imaging and quantification of hypoxia with PET probes is under study and may become a prerequisite for overcoming chemo- and radioresistance using radiosensitizing drugs or hypoxia-directed irradiation techniques and for monitoring the response to these techniques in selected groups of patients. Although (18)F-FDG PET/CT will remain the major clinical tool for monitoring treatment in HNSCC, other PET probes may have a role in identifying patients who are likely to benefit from treatment strategies that include biologic agents such as epidermal growth factor receptor inhibitors or VEGF inhibitors.

Prospective trial incorporating pre-/mid-treatment [18F]-misonidazole positron emission tomography for head-and-neck cancer patients undergoing concurrent chemoradiotherapy

PURPOSE

To report the results from a prospective study of a series of locoregionally advanced head-and-neck cancer patients treated with platinum-based chemotherapy and intensity-modulated radiotherapy and to discuss the findings of their pre-/mid-treatment [(18)F]-misonidazole ((18)F-FMISO) positron emission tomography (PET) scans.

METHODS AND MATERIALS

A total of 28 patients agreed to participate in this study. Of these 28 patients, 20 (90% with an oropharyngeal primary cancer) were able to undergo the requirements of the protocol. Each patient underwent four PET scans: one pretreatment fluorodeoxyglucose PET/computed tomography scan, two pretreatment (18)F-FMISO PET/computed tomography scans, and a third (18)F-FMISO PET (mid-treatment) scan performed 4 weeks after the start of chemoradiotherapy. The (18)F-FMISO PET scans were acquired 2-3 h after tracer administration. Patients were treated with 2-3 cycles of platinum-based chemotherapy concurrent with definitive intensity-modulated radiotherapy.

RESULTS

A heterogeneous distribution of (18)F-FMISO was noted in the primary and/or nodal disease in 90% of the patients. Two patients had persistent detectable hypoxia on their third mid-treatment (18)F-FMISO PET scan. One patient experienced regional/distant failure but had no detectable residual hypoxia on the mid-treatment (18)F-FMISO PET scan.

CONCLUSION

Excellent locoregional control was observed in this series of head-and-neck cancer patients treated with concurrent platinum-based chemotherapy and intensity-modulated radiotherapy despite evidence of detectable hypoxia on the pretreatment (18)F-FMISO PET/computed tomography scans of 18 of 20 patients. In this prospective study, neither the presence nor the absence of hypoxia, as defined by positive (18)F-FMISO findings on the mid-treatment PET scan, correlated with patient outcome. The results of this study have confirmed similar results reported previously.

Clinical utility of 18F-FDG PET/CT in assessing the neck after concurrent chemoradiotherapy for Locoregional advanced head and neck cancer

For patients with locoregional advanced head and neck squamous cell carcinoma (HNSCC), concurrent chemoradiotherapy is a widely accepted treatment, but the need for subsequent neck dissection remains controversial. We investigated the clinical utility of 18F-FDG PET/CT in this setting.

METHODS

In this Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPPA)-compliant retrospective study, we reviewed the records of patients with HNSCC who were treated by concurrent chemoradiation therapy between March 2002 and December 2004. Patients with lymph node metastases who underwent 18F-FDG PET/CT > or = 8 wk after the end of therapy were included. 18F-FDG PET/CT findings were validated by biopsy, histopathology of neck dissection specimens (n = 18), or clinical and imaging follow-up (median, 37 mo).

RESULTS

Sixty-five patients with a total of 84 heminecks could be evaluated. 18F-FDG PET/CT (visual analysis) detected residual nodal disease with a sensitivity of 71%, a specificity of 89%, a positive predictive value (PPV) of 38%, a negative predictive value (NPV) of 97%, and an accuracy of 88%. Twenty-nine heminecks contained residual enlarged lymph nodes (diameter, > or =1.0 cm), but viable tumor was found in only 5 of them. 18F-FDG PET/CT was true-positive in 4 and false-positive in 6 heminecks, but the NPV was high at 94%. Fifty-five heminecks contained no residual enlarged nodes, and PET/CT was true-negative in 50 of these, yielding a specificity of 96% and an NPV of 98%. Lack of residual lymphadenopathy on CT had an NPV of 96%. Finally, normal 18F-FDG PET/CT excluded residual disease at the primary site with a specificity of 95%, an NPV of 97%, and an accuracy of 92%.

CONCLUSION

In patients with HNSCC, normal 18F-FDG PET/CT after chemoradiotherapy has a high NPV and specificity for excluding residual locoregional disease. In patients without residual lymphadenopathy, neck dissection may be withheld safely. In patients with residual lymphadenopathy, a lack of abnormal 18F-FDG uptake in these nodes also excludes viable tumor with high certainty, but confirmation of these data in a prospective study may be necessary before negative 18F-FDG PET/CT may become the only, or at least most-decisive, criterion in the management of the neck after chemoradiotherapy.

Single agent bevacizumab and bevacizumab in combination with docetaxel and cisplatin as induction therapy for resectable IB-IIIA non-small cell lung cancer

18045

Background: Bevacizumab (Bev) improves response and survival in patients with advanced non-squamous lung cancer with chemotherapy however there are limited data as single agent therapy and in early stage NSCLC. Methods: Patients with resectable stage IB-IIIA NSCLC were eligible. Patients with adenocarcinoma (Cohort 1) received preoperative Bev and docetaxel and cisplatin (DC). Patients with squamous histology, central location or recent hemoptysis received DC induction therapy without Bev (Cohort 2). Cohort 1 received Bev (15 mg/kg) followed by CT 2 weeks later to assess single agent Bev response. Subsequently D (75 mg/m2) and C (75 mg/m2) were given q 3 weeks; an additional 2 cycles of Bev was administered with C2 and C3 of DC (total of 3 preoperative doses of Bev). Cohort 2 received DC alone followed by resection. Both cohorts received adjuvant Bev x 1 year. Study endpoints included response to single agent Bev, downstaging, safety and survival. Results: 19 patients of planned 70 were enrolled (11 Cohort 1 and 8 Cohort 2). On Cohort 1, there were 2 clinical stage IIB and 9 IIIA patients. After single agent Bev (by bimensional measurement), > 10% reduction in tumor size was observed after 2 weeks in 6/11 patients (- 20%, 15%, 16%, 15%, 13% and 20%). After Bev + DC, there were 6/10 (60%) PRs and DC delivery was 96%. 6/10 patient underwent R0 resection; 1 R2 and 2 were unresectable. 1 patient developed hemoptysis preoperatively and 1 patient developed an upper GI bleed post-operatively. There were otherwise no Bev related operative complications observed. 5/9 patients were downstaged by induction treatment. 3 patients received adjuvant bevacizumab to date (median 5.7 cycles). 8 patients were treated on Cohort 2 (3 with stage IB, 1 with IIB and 4 with IIIA). All 8 patients underwent R0 resection. DC delivery was 94% and there were 6/8 PRs. Downstaging was observed in 5/8 patients and 6/8 are receiving adjuvant Bev (median # cycles to date = 6.7). Conclusions: Bev as a single agent demonstrates regression of tumors after 2 weeks. To date, Bev has been safely administered in the neoadjuvant and adjuvant setting. Preoperative chemotherapy is well tolerated with more than 90% full dose drug delivery. The study is ongoing. Supported by Genentech, Inc.

[Table: see text]

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) as a predictor of response in head and neck squamous cell carcinoma (HNSCC)

6007

Background: We wish to assess on a preliminary basis whether pretreatment DCE-MRI predicts response to chemoradiation in HNSCC. Methods: Tumor perfusion was assessed in 14 patients (median age, 56y; 13 M, 1 F; squamous cell cancer 13, poorly differentiated carcinoma 1; base of tongue 6; tonsil 6; larynx 1; nasopharynx 1) with nodal metastases (size >1 cc for DCE-MRI; N1, 3; N2a, 2; N2b, 4; N2c, 4; N3, 1; Stage III, 3; Stage IVa, 10; Stage IVb, 1) prior to platin-based concurrent chemoradiation therapy. Data were acquired on a 1.5 Tesla clinical scanner with a standard MRI protocol using a clinical contrast agent (Gd-DTPA). The two compartment model analysis measured the rate constants of the contrast agent transfer between the lesion and plasma compartments (kep) and elimination by the plasma (kel). Each patient was assigned a single MR imaging parameter of uptake slope and compartmental model (Akep) on the basis of the histogram analysis of all individually fit tumor voxels. Histogram analysis calculated the amplitude (a), width (s), and median (μ) of the distribution from the fitting procedure. Overall response was determined approximately 2–5 months post treatment. Results: DCE-MRI data showed a rapid rise in the time intensity curves for viable appearing tumor, whereas muscle showed minimal signal enhancement. The mean Akep value was higher for complete responders (CR/near CR, n = 7) than for incomplete responders (ICR, n = 7; 3 partial response, 4 no response) (12.29/min±4.09 vs 7.11/min±2.51 [P = 0.04]. The preliminary histogram analysis for the slope showed that the width and median were able to differentiate between CR and ICR, P=0.039 and P=0.013 respectively, while amplitude was not significant (P=0.150). Conclusions: These preliminary data suggest that DCE-MRI may prove to be a useful predictor of response in HNSCC patients, and thus may enhance prognostication, patient selection, and treatment outcomes.

No significant financial relationships to disclose.

A phase II study of single agent depsipeptide (DEP) in patients (pts) with radioactive iodine (RAI)-refractory, metastatic, thyroid carcinoma: Preliminary toxicity and efficacy experience

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Background: RAI-refractory thyroid cancer carries a poor prognosis, and no effective systemic therapy exists. DEP is a potent histone deacetylase inhibitor with broad in vitro and phase I anti-tumor activity, and has restored sodium-iodide symporter expression and RAI avidity in thyroid cancer cell lines. Methods: Eligible pts have confirmed papillary, follicular, or Hürthle cell carcinoma, progressive measurable disease, and adequate hepatic/renal function. All pts are RAI-refractory by diagnostic RAI whole body scan (WBS). Prior chemotherapy in the recurrent/metastatic setting, and history of significant cardiac disease are exclusions. DEP 13 mg/m2 IV is given on day 1, 8, and 15, every 28 days. A novel Simon 2-stage design specifies an initial accrual of 21 pts, with expansion to 41 total pts if 2 RECIST responses or 6 pts with PFS at 6 months are observed. Primary outcome is RECIST response rate. Change in RAI avidity (by diagnostic RAI WBS) is a secondary outcome. Results: To date, 14 pts have been enrolled: female 50%, median age 62 (42–78), median Karnofsky 90 (70–100), papillary/follicular/Hürthle histology (7/1/6). Grade 3–5 toxicities possibly related to drug: grade 5 sudden death (1); no grade 4 toxicity; grade 3 toxicity - fatigue (1), dysphagia (1), dyspnea (1). No grade 3 thrombocytopenia (phase I DLT) has been observed. Grade 1 (6) and grade 2 (4) fatigue have been common. As a result of the grade 5 event, protocol accrual and treatment were suspended temporarily. After NCI-CTEP review, more restrictive cardiac exclusions were added and protocol accrual was resumed. Response at 2 months: stable disease (4); progression (2); inevaluable (6, due to protocol suspension); withdrew consent (1); too early (1). In a proof-of-principle event, clinically significant restoration of RAI avidity was observed in a 78 year-old woman with papillary carcinoma. Per protocol, she was taken off study and given treatment-dose RAI; post-therapy WBS confirmed dramatic RAI avidity. Conclusions: Preliminary signs of in vivo reversal of RAI resistance have been observed. Accrual continues with more restrictive cardiac exclusions, and close surveillance for cardiac events.

No significant financial relationships to disclose.

Direct interaction between BKCa potassium channel and microtubule-associated protein 1A

The BKCa channel, a potassium channel that is allosterically activated by voltage and calcium, is expressed in both excitable and non-excitable cells. The channel plays an important role in regulating membrane excitability. The channel activity can be modulated by post-translational modifications such as phosphorylation. Recently, hippocampal BKCa channels were shown to be directly modulated by assembly/disassembly of the submembranous actin cytoskeleton. Here, we report that the BKCa channel physically interacts with the light chain of microtubule associated protein 1A (MAP1A). The light chain was isolated in a yeast two-hybrid screen of a human brain cDNA library. The specificity of the interaction was demonstrated in biochemical experiments utilizing GST fusion protein pulldown assays and reciprocal co-immunoprecipitations from rat brain. Furthermore, utilizing immunofluorescence, the BKCa channel and MAP1A co-localize in the Purkinje cell layer of the cerebellum. These studies identify a novel interaction between the C-terminal tail of the BKCa channel and the light chain of MAP1A, which enables channel association with and modulation by the cytoskeleton.

Molecular BKology: the study of splicing and dicing

The activity of ion channels is regulated by several different mechanisms. Studies have been undertaken to determine how the large-conductance Ca(2+)-sensitive K(+) channel (the BK channel) is regulated. Fury et al. discuss how the presence or absence of alternatively spliced regions in the BK channel alpha subunit can act as a molecular switch by which different kinases activate the BK channel.

Thirteen anti-Sm monoclonal antibodies immunoprecipitate the three cytoplasmic snRNP core protein precursors in six distinct subsets

The small nuclear ribonucleoprotein particle (snRNP) common core proteins are the lupus-associated Sm autoantigens. In mouse fibroblasts the seven snRNP core proteins form a particle with a suggested stoichiometry of B2[D1,D2(E,F,G)2] D3. Core particle assembly occurs in the cytoplasm where newly synthesized snRNAs assemble with core proteins stored in three RNA-free complexes of (1) a 6S complex of [D1,D2(E,F,G)2] (2) a 20S complex of (B,D3 and an unidentified 70 kDa protein) and (3) a 2S-6S complex that minimally contains the B protein. In this report a panel of 13 anti-Sm monoclonal antibodies is shown to immunoprecipitate six different subsets of the cytoplasmic snRNP proteins. Four epitopes are shared by the three aforementioned complexes and five other epitopes are shared by two of the complexes. In addition, the 6S or 20S complexes are apparently disrupted by five of the antibodies. Kinetic studies show that the three cytoplasmic snRNP protein complexes have independent half-lives. These studies provide another approach for characterizing the Sm epitopes. They also complement previous in vitro snRNP assembly studies and suggest that snRNP core assembly occurs by the initial binding of snRNA to the 6S particle followed by addition of the B and D3 proteins.