The tumor microenvironment state associates with response to HPV therapeutic vaccination in patients with respiratory papillomatosis

Recurrent respiratory papillomatosis (RRP) is a rare, debilitating neoplastic disorder caused by chronic infection with human papillomavirus (HPV) type 6 or 11 and characterized by growth of papillomas in the upper aerodigestive tract. There is no approved medical therapy, and patients require repeated debulking procedures to maintain voice and airway function. PRGN-2012 is a gorilla adenovirus immune-therapeutic capable of enhancing HPV 6/11-specific T cell immunity. This first-in-human, phase 1 study (NCT04724980) of adjuvant PRGN-2012 treatment in adult patients with severe, aggressive RRP demonstrates the overall safety and clinically meaningful benefit observed with PRGN-2012, with a 50% complete response rate in patients treated at the highest dose. Responders demonstrate greater expansion of peripheral HPV-specific T cells compared with nonresponders. Additional correlative studies identify an association between reduced baseline papilloma HPV gene expression, greater interferon responses and expression of CXCL9 and CXCL10, and greater papilloma T cell infiltration in responders. Conversely, nonresponders were characterized by greater HPV and CXCL8 gene expression, increased neutrophilic cell infiltration, and reduced T cell papilloma infiltration. These results suggest that papilloma HPV gene expression may regulate interferon signaling and chemokine expression profiles within the tumor microenvironment that cooperate to govern clinical response to therapeutic HPV vaccination in patients with respiratory papillomatosis.

483 Initial safety results and immune responses induced by a novel human papillomavirus (HPV)-specific gorilla adenovirus immunotherapy vaccine, PRGN-2009, in patients with advanced HPV-associated cancers

Background

PRGN-2009 is a novel gorilla adenovirus vaccine containing 35 non-HLA-restricted epitopes of HPV 16 and 18 which is being tested in an open-label, NCI-sponsored, single-center Phase I/II study alone and combined with the bifunctional TGF-β ”trap”/anti-PD-L1 fusion protein bintrafusp alfa (BA) (NCT04432597).

Methods

For the Phase I of the trial, eligible patients are adults with previously treated (checkpoint blockade allowed) recurrent/metastatic HPV-associated cancers. Objectives are to assess the safety and determine the recommended phase 2 dose (RP2D) of PRGN-2009 alone and combined with BA. Treatment followed a single-agent 3+3 dose escalation at two dose levels of PRGN-2009 (dose level 1: 1x1011 viral particle units (VPU), dose level 2: 5x1011 VPU) subcutaneously Q2W for 3 times, then Q4W for up to one year in total. After determination of RP2D, a combination cohort of 10 patients treated with PRGN-2009 at the RP2D combined with BA (1200 mg IV Q2W for 52 weeks) opened. Peripheral blood mononuclear cells collected from patients before and after vaccination with PRGN-2009 were stimulated with overlapping peptide pools and assessed by intracellular cytokine staining to identify HPV-16 and HPV-18 specific T-cells, as well as T-cells targeting cascade antigens not encoded by the vaccine.

Results

Six patients were enrolled in the single-agent PRGN-2009 dose-escalation phase (3 with cervical cancer, 2 with anal cancer, 1 with vaginal cancer). Observed adverse events were Grade 1-2 flu-like syndrome (headache, body aches), injection site reactions (erythema, pruritus, soreness, localized edema), fatigue, and rash. There were no dose limiting toxicities, and 5x1011 VPU was selected as RP2D. Four patients had stable disease as best response, (one ongoing, 10 months on treatment).T-cells targeting HPV-16 and/or HPV-18 were increased after vaccination in 100% of patients, with 3/6 (50%) developing HPV-16 T cells and 5/6 (83%) developing HPV-18 T cells. In some patients, the magnitude and breadth of HPV-16 and HPV-18 specific T cells were notably increased after repeated vaccination. T cells that target the cascade antigens brachyury and MUC1 were also increased in all patients evaluated. Multifunctional T-cell responses against all these antigens were also developed after vaccination in the majority of patients. No differences in immunogenicity were noted between the two dose levels. Enrollment is underway in combination with BA. Updated data will be presented.

Conclusions

The Phase 1 results demonstrate the safety of single-agent PRGN-2009 and induction of anti-HPV T-cell immune responses, supporting the hypothesis that PRGN-2009 could potentially induce anti-tumor effects in HPV-associated cancers.

Acknowledgements

This research was supported in part by the Intramural Research Program of the NIH, NCI.

Trial Registration

NCT04432597

Ethics Approval

Approved by the NIH IRB (Ref No 543876). All participants have given informed consent before taking part in the study.

First-in-human phase I/II trial of PRGN-2009 vaccine as monotherapy or with bintrafusp alfa in patients with recurrent/metastatic (R/M) human papillomavirus (HPV)-associated cancers (HPVC) and as neoadjuvant/induction therapy in locoregionally advanced (LA) HPV oropharyngeal (OP) and sinonasal (SN) squamous cell cancer (SCC)

TPS6092

Background: R/M HPVC (cervical, anal, oropharyngeal, etc.) are incurable by current therapies. For newly diagnosed LA HPV-OPSCC standard-of-care (SOC) is radiotherapy ± chemotherapy (C/RT) or surgery ± adjuvant C/RT, with considerable risk of relapse. Newly diagnosed LA SNSCC treatment follows the OPSCC paradigm, and detection of HPV appears to confer improved prognosis. Neoadjuvant PD-1 immune checkpoint blockade (ICB) before surgery may improve RFS and is being evaluated in a multicenter phase III clinical trial (Keynote-689). PRGN-2009 (P) is a novel gorilla adenovirus vaccine containing 35 non-HLA-restricted epitopes of HPV 16 and 18 shown to induce HPV specific responses (preclinical models). Bintrafusp alfa (BA) is a bifunctional fusion protein targeting TGF-β and PD-L1 with promising activity in HPVC. This trial will evaluate the safety and activity of P/ P + BA in patients with previously treated R/M HPVC and as neoadjuvant/induction therapy before SOC surgery or C/RT in newly diagnosed LA HPV-OPSCC and HPV-SNSCC. Methods: This is a first-in-human, investigator-initiated, single-center phase I/II trial. Pts with previously treated (incl. ICB) R/M HPVC are eligible for Phase I: P dose escalation arm (3+3 design, 6-12 patients) testing 2 dose levels (1x1011, 5x1011 viral particle units, SC Q2W three times, then Q4W), and combination arm (10 patients) testing P (recommended phase 2 dose (RP2D), same schedule) + BA (1200 mg IV Q2W). Treatment (both arms) will continue until disease progression, unacceptable toxicity, decision to withdraw. Primary endpoint is safety. Secondary endpoints include ORR (RECIST 1.1), PFS, and OS. For Phase II, patients with newly diagnosed stage II/III (AJCC Cancer Staging Manual, 8th ed.) HPV-OPSCC and stage II/III/IVA/IVB HPV-SNSCC planned for SOC C/RT or surgery will be eligible for two treatment arms of 20+2 patients each (sequential): P arm and P + BA, to evaluate the treatment activity. All patients will have pre-treatment biopsy, receive two cycles of the study treatment at the NCI Clinical Center two weeks apart, followed by post-treatment biopsy and SOC treatment (at the referring institution) 4 weeks after the first study treatment. Primary endpoint is post-treatment ≥2-fold increase in tumor-infiltrating CD3+ cells. Secondary endpoints include RFS, OS. Exploratory endpoints for both arms include analyses of immune subsets, soluble factors, and HPV-specific immune responses in peripheral blood and tissue where available, and in Phase II sequencing (exome, scRNA), immune spatial profiling with multiplex immunofluorescence, and salivary HPV DNA. Clinical trial registry: NCT04432597. Clinical trial information: NCT04432597.

Indiplon: the development of a novel therapy for the treatment of sleep onset and sleep maintenance insomnia

Indiplon is a novel non-benzodiazepine sedative-hypnotic that modulates the GABAA receptor complex. It appears to be more selective for the alpha1-receptor subunit, associated with sedation, than other hypnotics. Two different formulations of indiplon have been developed: an immediate release (IR) version targeting sleep onset insomnia and a modified release (MR) version addressing sleep maintenance insomnia. Early results from clinical trials indicate that both formulations are well tolerated and effective at improving both objective and subjective measures of sleep. As of May 2006 indiplon-IR has been provisionally approved for use in the US market and discussions are continuing with the FDA regarding the MR formulation.

Effects of A1 adenosine receptor stimulation on the expression of genes involved in calcium homeostasis

We investigated whether A(1) adenosine receptor stimulation affects expression of genes involved in calcium homeostasis, including sarcolemmal L-type Ca(2+) channel, Na(+)/Ca(2+) exchanger, sarcoplasmic reticulum (SR) Ca(2+)-ATPase, phospholamban, or ryanodine receptor. Three models of A(1) stimulation were used: i) an acute model, i.e. isolated perfused rat hearts treated for 120 min with 15 nM R-phenylisopropyladenosine (R-PIA), an A(1) receptor agonist; ii) a subacute model, i.e. rats treated with 1.5 mg/kg R-PIA e.v. and sacrificed after 24 h; iii) a transgenic model, i.e. mice overexpressing A(1) adenosine receptors. In all models gene expression was determined by RT-PCR, and oxalate-supported Ca(2+) uptake, representing SR Ca(2+) uptake, was measured in the crude homogenate. Significant increase in the expression of the phospholamban gene was observed in each model of A(1) stimulation, while the expression of the other four genes was not significantly modified. In the acute model, SR Ca(2+) uptake was unaffected, however in the subacute and transgenic models uptake rate was significantly reduced. In parallel experiments, hearts obtained from the subacute model demonstrated a significant reduction in irreversible tissue injury from 30 min of ischemia and 120 min of reperfusion. Increased resistance to ischemia has already been reported also in our transgenic model. In conclusion, A(1) adenosine receptor stimulation up-regulates phospholamban gene expression, which leads within 24 h to a reduced rate of SR Ca(2+) uptake. Changes in Ca(2+) homeostasis might contribute to the delayed cardioprotective effect of adenosine.

Myocardial function following cold ischemic storage is improved by cardiac-specific overexpression of A1-adenosine receptors

Cold ischemic storage of hearts for transplantation is limited to 4-6 h, and therefore the development of strategies to extend preservation time may increase the donor pool of hearts. Overexpression of A1-adenosine receptors (A1AR) can protect hearts from acute ischemic injury, and the purpose of this study was to test the hypothesis that overexpression of A1AR will improve tolerance to longer periods of cold ischemic preservation. Hearts from 18 wild type and 16 transgenic mice with overexpression of A1AR (A1AR Trans) were isolated and perfused, and then subjected to 18 h of preservation in 5 degrees C University of Wisconsin solution followed by 2 h of reperfusion. Left ventricular end diastolic pressure and left ventricular developed pressure were measured as indices of ventricular function. Cell viability was assessed by determination of infarct size and myocardial cell apoptosis. A1AR Trans hearts showed improved function following 18 h of ischemia, as shown by lower end diastolic pressure (p < 0.05) and higher recovery of left ventricular developed pressure (p < 0.05) during reperfusion. A1AR Trans hearts had markedly reduced infarct size (p < 0.05) and decreased apoptosis (p < 0.05). Overexpression of cardiac A1AR imparts cardioprotection during long-term cold ischemic preservation.

Altered sinus nodal and atrioventricular nodal function in freely moving mice overexpressing the A1 adenosine receptor

To investigate whether altered function of adenosine receptors could contribute to sinus node or atrioventricular (AV) nodal dysfunction in conscious mammals, we studied transgenic (TG) mice with cardiac-specific overexpression of the A1 adenosine receptor (A1AR). A Holter ECG was recorded in seven freely moving littermate pairs of mice during normal activity, exercise (5 min of swimming), and 1 h after exercise. TG mice had lower maximal heart rates (HR) than wild-type (WT) mice (normal activity: 437 +/- 18 vs. 522 +/- 24 beats/min, P < 0.05; exercise: 650 +/- 13 vs. 765 +/- 28 beats/min, P < 0.05; 1 h after exercise: 588 +/- 18 vs. 720 +/- 12 beats/min, P < 0.05; all values are means +/- SE). Mean HR was lower during exercise (589 +/- 16 vs. 698 +/- 34 beats/min, P < 0.05) and after exercise (495 +/- 16 vs. 592 +/- 27 beats/min, P < 0.05). Minimal HR was not different between genotypes. HR variability (SD of RR intervals) was reduced by 30% (P < 0.05) in TG compared with WT mice. Pertussis toxin (n = 4 pairs, 150 microg/kg ip) reversed bradycardia after 48 h. TG mice showed first-degree AV nodal block (PQ interval: 42 +/- 2 vs. 37 +/- 2 ms, P < 0.05), which was diminished but not abolished by pertussis toxin. Isolated Langendorff-perfused TG hearts developed spontaneous atrial arrhythmias (3 of 6 TG mice vs. 0 of 9 WT mice, P < 0.05). In conclusion, A1AR regulate sinus nodal and AV nodal function in the mammalian heart in vivo. Enhanced expression of A1AR causes sinus nodal and AV nodal dysfunction and supraventricular arrhythmias.

Pertussis toxin sensitive and insensitive effects of adenosine and carbachol in murine atria overexpressing A(1)-adenosine receptors

1 It was investigated how A(1)-adenosine receptor overexpression alters the effects of carbachol on force of contraction and beating rate in isolated murine atria. Moreover, the influence of pertussis toxin on the inotropic and chronotropic effects of adenosine and carbachol in A(1)-adenosine receptor overexpressing atria was studied. 2 Adenosine and carbachol alone exerted negative inotropic and chronotropic effects in electrically driven left atrium or spontaneously beating right atrium of wild-type mice. 3 These effects were abolished or reversed by pre-treatment of animals with pertussis toxin which can interfere with signal transduction through G-proteins. 4 Adenosine and carbachol exerted positive inotropic but negative chronotropic effects in atrium overexpressing A(1)-adenosine receptors from transgenic mice. 5 The positive inotropic effects of adenosine and carbachol were qualitatively unaltered whereas the negative chronotropic effects were abolished or reversed in atrium overexpressing A(1)-adenosine receptors after pre-treatment by pertussis toxin. 6 Qualitatively similar effects for adenosine and carbachol were noted in the presence of isoprenaline, beta-adrenoceptor agonist. 7 It is concluded that overexpression of A(1)-adenosine receptors also affects the signal transduction of other heptahelical, G-protein coupled receptors like the M-cholinoceptor in the heart. The chronotropic but not the inotropic effects of adenosine and carbachol in transgenic atrium were mediated via pertussis toxin sensitive G-proteins.

Pertussis toxin sensitive and insensitive effects of adenosine and carbachol in murine atria overexpressing A(1)-adenosine receptors

1 It was investigated how A(1)-adenosine receptor overexpression alters the effects of carbachol on force of contraction and beating rate in isolated murine atria. Moreover, the influence of pertussis toxin on the inotropic and chronotropic effects of adenosine and carbachol in A(1)-adenosine receptor overexpressing atria was studied. 2 Adenosine and carbachol alone exerted negative inotropic and chronotropic effects in electrically driven left atrium or spontaneously beating right atrium of wild-type mice. 3 These effects were abolished or reversed by pre-treatment of animals with pertussis toxin which can interfere with signal transduction through G-proteins. 4 Adenosine and carbachol exerted positive inotropic but negative chronotropic effects in atrium overexpressing A(1)-adenosine receptors from transgenic mice. 5 The positive inotropic effects of adenosine and carbachol were qualitatively unaltered whereas the negative chronotropic effects were abolished or reversed in atrium overexpressing A(1)-adenosine receptors after pre-treatment by pertussis toxin. 6 Qualitatively similar effects for adenosine and carbachol were noted in the presence of isoprenaline, beta-adrenoceptor agonist. 7 It is concluded that overexpression of A(1)-adenosine receptors also affects the signal transduction of other heptahelical, G-protein coupled receptors like the M-cholinoceptor in the heart. The chronotropic but not the inotropic effects of adenosine and carbachol in transgenic atrium were mediated via pertussis toxin sensitive G-proteins.

Circulating metabolites of the human immunodeficiency virus protease inhibitor nelfinavir in humans: structural identification, levels in plasma, and antiviral activities

Nelfinavir mesylate (Viracept, formally AG1343) is a potent and orally bioavailable human immunodeficiency virus (HIV) type 1 (HIV-1) protease inhibitor (K(i) = 2 nM) and is being widely prescribed in combination with HIV reverse transcriptase inhibitors for the treatment of HIV infection. The current studies evaluated the presence of metabolites circulating in plasma following the oral administration of nelfinavir to healthy volunteers and HIV-infected patients, as well as the levels in plasma and antiviral activities of these metabolites. The results showed that the parent drug was the major circulating chemical species, followed in decreasing abundance by its hydroxy-t-butylamide metabolite (M8) and 3'-methoxy-4'-hydroxynelfinavir (M1). Antiviral assays with HIV-1 strain RF-infected CEM-SS cells showed that the 50% effective concentrations (EC50) of nelfinavir, M8, and M1 were 30, 34, and 151 nM, respectively, and that the corresponding EC50 against another HIV-1 strain, IIIB, in MT-2 cells were 60, 86, and 653 nM. Therefore, apparently similar in vitro antiviral activities were demonstrated for nelfinavir and M8, whereas an approximately 5- to 11-fold-lower level of antiviral activity was observed for M1. The active metabolite, M8, showed a degree of binding to human plasma proteins similar to that of nelfinavir (ca. 98%). Concentrations in plasma of nelfinavir and its metabolites in 10 HIV-positive patients receiving nelfinavir therapy (750 mg three times per day) were determined by a liquid chromatography tandem mass spectrometry assay. At steady state (day 28), the mean plasma nelfinavir concentrations ranged from 1.73 to 4.96 microM and the M8 concentrations ranged from 0.55 to 1.96 microM, whereas the M1 concentrations were low and ranged from 0.09 to 0.19 microM. In conclusion, the findings from the current studies suggest that, in humans, nelfinavir forms an active metabolite circulating at appreciable levels in plasma. The active metabolite M8 may account for some of the antiviral activity associated with nelfinavir in the treatment of HIV disease.

Spontaneous perforation of the bile duct

We present a classic but rare case of spontaneous perforation of the bile duct in infancy and a previously undescribed treatment technique. The patient, a male age 5 weeks, was admitted with abdominal distention, ascites, and conjugated hyperbilirubinemia. Ultrasound revealed ascites but did not provide visualization of the gallbladder. Although hepatobiliary scintigraphy with technetium [dimethyl iminodiacetic acid (HIDA scan)] showed normal uptake peritoneal excretion suggested perforation of the common bile duct (CBD). Exploratory laparotomy revealed 200 cm3 dark amber ascitic fluid in the peritoneal cavity and cholestasis of the liver. Intraoperative cholangiogram performed via the gallbladder showed a large perforation at the cystic duct/CBD junction. The perforation was large and leakage of contrast prevented demonstration of the distal CBD despite our attempt to primarily repair the perforation. The CBD was explored; a T-tube was placed. T-tube cholangiogram demonstrated flow of contrast into the duodenum. A large leak remained at the cystic CBD junction. A cholecystectomy was performed and a vascularized flap of the gallbladder wall was used to repair the CBD over the T-tube. The T-tube was clamped intermittently beginning 3 weeks postoperatively. T-tube cholangiogram performed 6 weeks postoperatively revealed no extravasation and normal intra- and extrahepatic biliary tree. The T-tube was subsequently discontinued and liver function tests remained normal at 6 months follow-up.