[The relationship of mental health providers with health insurers; an exploration]

BACKGROUND

In 2020, Zorgverzekeraars Nederland (ZN), the umbrella organization of nine health insurers in The Netherlands. presented a vision of the future of mental health care in the Netherlands in ‘De GGZ in 2025. Vergezicht op de geestelijke gezondheidszorg’ (‘Outlook on mental health care’). This document can be seen as marking the fact that key stakeholders share a common vision on the future of the GGZ in the Netherlands. Contracting care is often difficult. The tension between providing quality and sufficient care and available funding leads to friction. Congruence in vision, goals and practices are important conditions for adequate relationship building. Does the vision document contribute to this?

AIM

To discuss the experiences of mental health care administrators and health insurers in contracting and collaboration.

METHOD

Conducting interviews with both directors of mental health institutions and the strategic (policy) advisors of health insurers. In the approach we used the salience model.

RESULTS

The relationship between mental health care administrators and health insurers is perceived to be distrustful and complex, and has deteriorated slightly in 2021 compared to 2019. Perceived power, legitimacy and urgency affect the relationship. Almost all health insurers are characterized as dominant stakeholders based on the salience model. Both parties are open to improving the relationship, which requires more transparency and mutual understanding.

CONCLUSION

With the supported content of the vision document, there is to some extent shared governance. The change steps (shared innovation) considered desirable will be promoted by partly granting the intended benefits to each other (shared savings).

An evaluation of the safety and immunogenicity of MVC-COV1901: Results of an interim analysis of a phase III, parallel group, randomized, double-blind, active-controlled immunobridging study in Paraguay

BACKGROUND

Data from previous studies of the MVC-COV1901 vaccine, a subunit vaccine against SARS-CoV-2 based on the stable prefusion spike protein (S-2P) adjuvanted with CpG 1018 adjuvant and aluminum hydroxide, suggest that the vaccine is generally safe and elicits a good immune response in healthy adults and adolescents. By comparing with AZD1222, this study adds to the findings from previous trials and further evaluates the breadth of protection offered by MVC-COV1901.

METHODS

In this phase 3, parallel group, randomized, double-blind, active-controlled trial conducted in 2 sites in Paraguay, we assigned adults aged 18-91 years in a 1:1 ratio to receive intramuscular doses of MVC-COV1901 or AZD1222 administered as scheduled in the clinical trial. Serum samples were collected on the day of vaccination and 14 days after the second dose. Primary and secondary safety and immunogenicity endpoints were assessed. In addition, other outcomes investigated were cross-reactive immunity against the Omicron strain and the induction of IgG subclasses.

RESULTS

A total of 1,030 participants underwent randomization. Safety data was derived from this set while primary immunogenicity data involved a per-protocol immunogenicity (PPI) subset including 225 participants. Among the participants, 58% are seropositive at baseline. When compared against AZD1222, MVC-COV1901 exhibited superiority in terms of neutralizing antibody titers and non-inferiority in terms of seroconversion rates. Reactogenicity was generally mild and no serious adverse event was attributable to MVC-COV1901. Both vaccines have a Th1-biased response predominated by the production of IgG1 and IgG3 subclasses. Omicron-neutralizing titers were 44.5 times lower compared to wildtype-neutralizing titers among seronegative individuals at baseline. This fold-reduction was 3.0 times among the seropositive.

CONCLUSION

Safety and immunogenicity data of MVC-COV1901 from the study in Paraguay confirm previous results. The previous infection coupled with vaccination of this vaccine may offer protection against the Omicron strain though its durability is still unknown.

121. Safety, Tolerability, and Pertussis Immunogenicity Findings From a Randomized, Participant-Blinded, Active-Controlled, Dose-Escalating, Phase 1 Trial of a Tetanus/Diphtheria/Pertussis Booster Vaccine (Tdap-1018 CpG Adjuvanted) Compared With Boostrix in Healthy Adults Aged 18 to 22 Years

Background

Bordetella pertussis is a gram-negative bacterium causing the highly contagious respiratory infection pertussis in over 151 000 individuals annually worldwide. A tetanus/diphtheria/pertussis (Tdap) vaccine combined with CpG 1018 adjuvant (Tdap-1018) may induce higher antibody titers than existing aluminum-adjuvanted Tdap vaccines used as a booster in adults.

Methods

In this randomized, active-controlled, participant-blinded, phase 1 trial, healthy adults aged 18 to 22 years received 1 booster injection of Tdap-1018 (with same Tdap composition as in Boostrix and escalating CpG 1018 dose of 1500 µg and 3000 µg) or Boostrix on Day 1. Pertussis immunogenicity evaluations assessed booster response rates (BRRs) for anti-pertussis toxin (anti-PT), anti-filamentous hemagglutinin (anti-FHA), and anti-pertactin (anti-PRN) antibodies, and systems serology at Week 4 post-vaccination. Safety and tolerability were assessed for solicited local and systemic post-injection reactions for 7 days and unsolicited adverse events for 12 weeks after vaccination.

Results

Of the 87 enrolled adult participants, 84 had post-vaccination immunogenicity results. The median age was 19.0 years, 35% were men, and 83% were white. At Week 4, BRRs in the Tdap-1018 3000 µg group were statistically significantly higher (based on lower 95% confidence interval [CI] >0%) than the Boostrix group for anti-PT (difference in BRRs 22.2% [95% CI: 1.5%–42.8%]) and anti-PRN (22.2% [95% CI: 8.2%–40.9%]) antibodies, and similar for anti-FHA (14.8% [95% CI: -2.6%–33.9%]) antibodies (Table). Tdap-1018 1500 µg, Tdap-1018 3000 µg, and Boostrix were generally well tolerated with no observed safety concerns.

Conclusion

In this phase 1 trial, both dose levels of Tdap-1018 were generally well tolerated. Tdap-1018 3000 µg induced statistically significantly higher BRRs than Boostrix for anti-PT and anti-PRN, and a similar response for anti-FHA antibodies.

Disclosures

Robert Janssen, MD, Dynavax Technologies Corporation: employee|Dynavax Technologies Corporation: Stocks/Bonds Tammy Boyce, MEd, Dynavax Technologies Corporation: Employee|Dynavax Technologies Corporation: Stocks/Bonds Fang Xie, PhD, Dynavax Technologies Corporation: Employee|Dynavax Technologies Corporation: Stocks/Bonds Olivier Godeaux, MD, MPH, Dynavax: Advisor/Consultant.

An Immunobridging Study to Evaluate the Neutralizing Antibody Titer in Adults Immunized with Two Doses of Either ChAdOx1-nCov-19 (AstraZeneca) or MVC-COV1901

Rapid development and deployment of vaccines is crucial to control the continuously evolving COVID-19 pandemic. The placebo-controlled phase 3 efficacy trial is still the standard for authorizing vaccines in the majority of the world. However, due to a lack of eligible participants in parts of the world, this has not always been feasible. Recently, the Taiwan Food and Drug Administration, following the consensus of the International Coalition of Medicines Regulatory Authorities (ICMRA), adopted the use of immunobridging studies as acceptable for authorizing COVID-19 vaccines in lieu of efficacy data. Here, we describe a study in which our candidate vaccine, MVC-COV1901, an adjuvanted protein subunit vaccine, has been granted emergency use authorization (EUA) in Taiwan based on a noninferiority immunobridging study. Immunogenicity results from the per protocol immunogenicity (PPI) subset (n = 903) from the MVC-COV1901 phase 2 trial were compared with results from 200 subjects who had received an adenovirus vector vaccine, AstraZeneca ChAdOx nCOV-19 (AZD1222), in a separate study. The lower bound of the 95% confidence interval (CI) of the geometric mean titer (GMT) ratio comparing MVC-COV1901 to AZD1222 was 3.4. The lower bound of the 95% CI of the sero-response rate was 95.5%. Both the GMT ratio and sero-response rate exceeded the criteria established by the Taiwan regulatory authority, leading to EUA approval of MVC-COV1901 in Taiwan.

Safety and immunogenicity of HepB-CpG in women with documented pregnancies post-vaccination: A retrospective chart review

BACKGROUND

There are currently no published data on the use of HepB-CpG (HEPLISAV-B®) during pregnancy or in women with documented pregnancies in the post-vaccination period. We aimed to evaluate data from the clinical development program of HepB-CpG in women who became pregnant during study participation and follow up.

METHODS

We identified all study participants in the HepB-CpG pivotal pre-licensure clinical trials that had documented pregnancies during study follow up. We measured immunogenicity among study participants in the HepB-CpG (Heplisav-B®) arm compared to the HepB-alum (Engerix-B®) arm of the studies by comparing seroprotection rates (SPRs; anti-HBs ≥ 10 mIU/mL) and geometric mean concentrations (GMCs) of anti-HBs, obtained with FDA approved anti-HBsAg antibody assays at prespecified time points up to 28 weeks of follow up. Pregnancy outcomes were ascertained by chart review of extracted medical records of study participants.

RESULTS

We identified 40 documented pregnancies in the HepB-CpG arm and 19 documented pregnancies in the HepB-alum arm. Among subjects with documentation of seroprotection rates, 97.2% (95% CI 85.5-99.9) were seroprotected in the HepB-CpG arm and 66.7% (95% CI 41.0-86.7) were seroprotected in the HepB-alum arm. In the HepB-CpG arm, thirty-six study participants from the pivotal trials had reported pregnancy outcomes, the majority, 21/36 (58%) had a healthy term delivery, with 3/36 (8%) with spontaneous abortions, 1/36 (3%) congenital anomaly, and 2/36 (6%) had preterm birth. In the HepB-alum arm, 10/17 (59%) had healthy term deliveries, with 2/17 (12%) had spontaneous abortions and 1/17 (6%) had congenital anomaly.

CONCLUSIONS

These limited data suggest that HepB-CpG is immunogenic in women who become pregnant after vaccination, and pregnancy outcomes appear to be similar to women who received HepB-alum prior to pregnancy. These results need to be further verified with larger prospective studies with HBV vaccine administration during pregnancy.

Intralesional SD-101 in Combination with Pembrolizumab in Anti-PD-1 Treatment-Naïve Head and Neck Squamous Cell Carcinoma: Results from a Multicenter, Phase II Trial

PURPOSE

To determine whether SD-101, a Toll-like receptor 9 agonist, potentiates the antitumor activity of anti-PD-1 antibodies in patients with anti-PD-1/PD-L1 naïve, recurrent/metastatic head and neck squamous cell carcinoma (HNSCC).

PATIENTS AND METHODS

Patients with PD-1 Ab-naïve HNSCC received either 2 mg SD-101 injected in one to four lesions or 8 mg SD-101 injected into a single lesion weekly × 4 doses then every 3 weeks × 7 doses. Pembrolizumab was administered at 200 mg every 3 weeks.

RESULTS

A total of 28 patients received 2 mg and 23 received 8 mg per injection, respectively. A total of 76% of patients had received prior systemic therapy. Combined positive score was ≥1 to < 20 in 35 patients (70%) and ≥ 20 in 15 patients (30%) of 50 patients with available data. There were 12 patients with grade ≥3 treatment-related adverse events (24%), and no treatment-related deaths. The objective response rate was 24% including 2 complete and 10 partial responses. The median duration of response was 7.0 [95% confidence interval (CI): 2.1-11.1] months. The response rate was higher in human papillomavirus-positive (HPV+) patients (44%, N = 16). Responses were not associated with PD-L1 expression levels or IFNγ-related gene expression at baseline. Responses were observed both in injected (32%) and in noninjected lesions (29%). Progression-free and overall survival at 9 months were 19.0% (95% CI: 9.1-31.7) and 64.7% (95% CI: 45.3-78.7), respectively.

CONCLUSIONS

SD-101 combined with pembrolizumab induced objective responses, especially in HPV+ tumors, which were frequently associated with increased intratumoral inflammation and effector immune cell activity.

A Phase Ib Open-Label, Multicenter Study of Inhaled DV281, a TLR9 Agonist, in Combination with Nivolumab in Patients with Advanced or Metastatic Non-small Cell Lung Cancer

PURPOSE

Although PD-(L)1 inhibitors have shown efficacy in advanced/metastatic non-small cell lung cancer (NSCLC), many patients do not respond to this treatment and more effective combinations with acceptable toxicities are needed. To assess the potential benefit of combining localized innate immune stimulation with checkpoint blockade, the TLR9 agonist DV281 was combined with nivolumab in a phase Ib study.

PATIENTS AND METHODS

Patients after one or two prior lines of systemic therapy were enrolled in a dose-escalation study with a 3+3 design. DV281 was administered via inhalation in five dose cohorts at 1 to 25 mg; nivolumab 240 mg was administered intravenously every 2 weeks. Safety, tolerability, pharmacodynamics, and response to treatment were assessed.

RESULTS

Twenty-six patients with advanced NSCLC enrolled. Baseline programmed death ligand 1 (PD-L1) expression was present in 16 patients (61.5%); 21 (80.7%) had received previous anti-PD-1/PD-L1. Thirteen patients (50%) had stable disease, nine (34.6%) had progressive disease, and four (15.4%) were not evaluable. Median duration of disease control was 124 days. Adverse events were seen in 16 patients (61.5%), mostly grade 1/2 chills, fatigue, flu-like symptoms, diarrhea, and rash; there was only one grade 3 adverse event (dyspnea). Pharmacodynamic assessment, measured by IFN- inducible gene expression, showed target engagement in all dose cohorts. Systemic pharmacodynamic responses plateaued in the 2 highest dose cohorts.

CONCLUSIONS

DV281 with nivolumab was well tolerated with target engagement observed at every dose. Pharmacodynamic advantages at doses above 10 mg were unclear. The long duration of disease control in 50% of patients suggests clinically relevant activity in this population of heavily pretreated patients.

Safety and immunogenicity of a Recombinant Stabilized Prefusion SARS-CoV-2 Spike Protein Vaccine (MVC-COV1901) Adjuvanted with CpG 1018 and Aluminum Hydroxide in healthy adults: A Phase 1, dose-escalation study

BACKGROUND

This was a phase 1, dose-escalation open-label trial to evaluate the safety and immunogenicity of MVC-COV1901, a SARS-CoV-2 S-2P protein vaccine adjuvanted with aluminum hydroxide and CpG 1018.

METHODS

Between September 28 and November 13 2020, 77 participants were screened. Of these, 45 healthy adults from 20 to 49 years of age were to be administered two doses of MVC-COV1901 in doses of 5 μg, 15 μg, or 25 μg of spike protein at 28 days apart. There were 15 participants in each dose group; all were followed for 28 days after the second dose at the time of the interim analysis. Adverse events and laboratory data were recorded for the safety evaluation. Blood samples were collected for humoral, and cellular immune response at various time points. Trial Registration: ClinicalTrials.gov NCT04487210.

FINDINGS

Solicited adverse events were mostly mild and similar. No subject experienced fever. After the second dose, the geometric mean titers (GMTs) for SARS-CoV-2 spike-specific immunoglobulin G were 7178.2, 7746.1, 11,220.6 in the 5 μg, 15 μg, and 25 μg dose groups, respectively. The neutralizing activity were detected in both methods. (Day 43 GMTs, 538.5, 993.1, and 1905.8 for pseudovirus; and 33.3, 76.3, and 167.4 for wild-type virus). The cellular immune response induced by MVC-COV1901 demonstrated substantially higher numbers of IFN-γ- producing cells, suggesting a Th1-skewed immune response.

INTERPRETATION

The MVC-COV1901 vaccine was well tolerated and elicited robust immune responses and is suitable for further development.

FUNDING

Medigen Vaccine Biologics Corporation.

Association of Number of Doses With Hepatitis B Vaccine Series Completion in US Adults

IMPORTANCE

Receipt of hepatitis B virus vaccine is important to prevent infection. However, adherence to the hepatitis B vaccine series among adults at risk of infection has been low.

OBJECTIVE

To assess whether recipients of a 2-dose hepatitis B vaccine with cytosine phosphoguanine adjuvant (HepB-CpG vaccine; Heplisav-B) are more likely to complete their series compared with recipients of a 3-dose vaccine with alum adjuvant (comparator vaccine; Engerix-B [HepB-alum]).

DESIGN, SETTING, AND PARTICIPANTS

This nested cohort study was conducted from August 7 to December 31, 2018, at Kaiser Permanente Southern California, an integrated health care system with a diverse population of approximately 4.6 million members. Adults not receiving dialysis who received a first dose of a hepatitis B vaccine series in family practice or internal medicine departments of 15 Kaiser Permanente Southern California medical centers were followed up through electronic health records for up to 1 year after receipt of the first dose. Data were analyzed from March 16 to September 23, 2020.

EXPOSURES

Receipt of a first dose of the HepB-CpG vaccine (2-dose vaccine) vs receipt of a first dose of the HepB-alum vaccine (3-dose vaccine).

MAIN OUTCOMES AND MEASURES

Series completion within the recommended vaccine schedule plus 3 months (primary outcome) and series completion within 1 year after receipt of the first dose (secondary outcome).

RESULTS

Of 4727 individuals who initiated the HepB-CpG vaccine series and 6161 individuals who initiated the HepB-alum vaccine series included in the study, 2876 (60.8%) and 3789 (61.5%), respectively, were ages 40 to 59 years, 2415 (51.1%) and 3113 (50.5%) were male, and 2364 (50.0%) and 2881 (46.8%) were Hispanic. The vaccine series was completed within the recommended schedule plus 3 months for 2111 (44.7%) individuals who initiated the HepB-CpG vaccine series and 1607 (26.1%) individuals who initiated the HepB-alum vaccine series, and within 1 year for 2858 (60.5%) and 1989 (32.3%) individuals, respectively. The individuals who initiated the HepB-CpG vaccine series were significantly more likely to complete the series (adjusted relative risk, 1.77; 95% CI, 1.68-1.87). Results were consistent across clinical and demographic strata.

CONCLUSIONS AND RELEVANCE

In this study, use of the HepB-CpG vaccine was associated with hepatitis B vaccine series completion, but tailored strategies to increase completion of hepatitis B vaccine series are warranted.

[Rheumatoid arthritis: more than a joint disease]

Rheumatoid arthritis (RA), one of the most common autoimmune disorders, mostly manifests itself as polyarthritis. However, extra-articular organ manifestations can also occur, even though their incidence has decreased substantially due to effective treatment with disease-modifying anti-rheumatic drugs. In this article we describe three patient cases of extra-articular manifestations in RA in the absence of prominent arthritis. The diversity of symptoms in RA can be of interest to different medical specialties who will occasionally encounter them in daily practice.

Recoil-Induced Asymmetry of Nondipole Molecular Frame Photoelectron Angular Distributions in the Hard X-ray Regime

We investigate angular emission distributions of the 1s photoelectrons of N_{2} ionized by linearly polarized synchrotron radiation at hν=40  keV. As expected, nondipole contributions cause a very strong forward-backward asymmetry in the measured emission distributions. In addition, we observe an unexpected asymmetry with respect to the polarization direction, which depends on the direction of the molecular fragmentation. In particular, photoelectrons are predominantly emitted in the direction of the forward nitrogen atom. This observation cannot be explained via asymmetries introduced by the initial bound and final continuum electronic states of the oriented molecule. The present simulations assign this asymmetry to a novel nontrivial effect of the recoil imposed to the nuclei by the fast photoelectrons and high-energy photons, which results in a propensity for the ions to break up along the axis of the recoil momentum. The results are of particular importance for the interpretation of future experiments at x-ray free electron lasers operating in the few tens of keV regime, where such nondipole and recoil effects will be essential.

Photon-Momentum-Induced Molecular Dynamics in Photoionization of N_{2} at hν=40 keV

We investigate K-shell ionization of N_{2} at 40 keV photon energy. Using a cold target recoil ion momentum spectroscopy reaction microscope, we determine the vector momenta of the photoelectron, the Auger electron, and both N^{+} fragments. These fully differential data show that the dissociation process of the N_{2}^{2+} ion is significantly modified not only by the recoil momentum of the photoelectron but also by the photon momentum and the momentum of the emitted Auger electron. We find that the recoil energy introduced by the photon and the photoelectron momentum is partitioned with a ratio of approximately 30∶70 between the Auger electron and fragment ion kinetic energies, respectively. We also observe that the photon momentum induces an additional rotation of the molecular ion.

286. Hepatitis B Vaccine Compliance: Comparing 2-Dose and 3-Dose Vaccines

Background

Less than 1 in 3 US adults who initiated the 3-dose (0, 1, 6 months) hepatitis B vaccine series have completed it. HepB-CpG (Heplisav-B; Dynavax) is a new licensed adjuvanted vaccine that requires only 2 doses (0, 1 month). As part of a cluster study performed at Kaiser Permanente Southern California, we compared compliance with second dose and series completion for HepB-CpG vs. comparator vaccine (Engerix-B; GlaxoSmithKline) recipients.

Methods

The cohort included adults not on dialysis who received their first dose of hepatitis B vaccine in family or internal medicine departments from 8/7/2018 to 2/1/2019. Second dose compliance was assessed for the full cohort, but series completion was assessed for a subset vaccinated from August 7, 2018 to September 30, 2018 to allow at least 6 months’ follow-up. Compliance rates were estimated using the Kaplan Meier method. Adjusted hazard ratios (aHR) were estimated using Cox proportional hazard regression with robust variance to account for within medical center correlation, adjusting for age, race/ethnicity, census block income and education, prior healthcare utilization, and factors that trigger alerts for hepatitis B vaccination (diabetes and testing for sexually transmitted infections).

Results

There were 6500 HepB-CpG and 7733 comparator vaccine recipients (1,442 and 2,604 prior to September 30, 2018). Rates of second dose compliance at 60 days were 32.9% for HepB-CpG and 29.1% for comparator vaccine, and rates of series completion at 210 days were 56.9% and 20.6%. There was no significant difference in second dose compliance (aHR 1.14, 95% CI: 0.91, 1.47), but HepB-CpG recipients were 5 times more likely to complete the series (aHR 5.17; 95% CI: 3.84, 6.98). Second dose compliance and series completion were significantly less likely among Blacks compared with Whites and significantly more likely among Asians, adults ≥60 years compared with those < 30 years, and adults living in census blocks with a median annual income of $40,000–69,000 compared with < $40,000.

Conclusion

Overall, second dose compliance was similar, but series completion was better for HepB-CpG recipients than comparator vaccine recipients, suggesting that the 2-dose vaccine could lead to improvements in coverage and protection against hepatitis B virus.

Disclosures

All authors: No reported disclosures.

Abstract CT224: Phase Ib/II, open label, multicenter study of inhaled DV281, a Toll-like receptor 9 agonist, in combination with nivolumab in patients with advanced or metastatic non small cell lung cancer (NSCLC)

Background and Objectives: DV281 is a synthetic CpG-ODN agonist of TLR9 that stimulates dendritic cells to release IFN-alpha and mature into antigen presenting cells to activate T cell anti-tumor responses. Nivolumab is a PD-1 inhibitor that has demonstrated activity in advanced/metastatic NSCLC. Study DV9- NSC-01 (NCT03326752) is a phase 1b/2 study to assess safety and pharmacodynamic activity of DV281 in combination with nivolumab in patients with advanced or metastatic NSCLC and to determine the recommended dose for expansion.

Methods: Anti-PD-1/L1 experienced or naïve patients were enrolled in 2L or 3L NSCLC in the escalation phase, 3+3 design: 5 dose cohorts, with intra-patient dose escalation between the first 2 monotherapy doses: cohort 1: 1 mg; cohort 2: 1 to 3 mg; cohort 3: 3 to 10 mg; cohort 4: 10 to 15 mg; cohort 5: 15 to 25 mg. Nivolumab was administered at 240 mg Q2w. Safety was primary objective and pharmacodynamic effects including IFN-inducible gene expression were key secondary objective. DV281 is administered via inhalation, first alone, weekly for 2 doses, then 6 doses weekly with nivolumab, followed by a 5 week off period of DV281, while continuing nivolumab, then DV281 with intravenous nivolumab Q2w for an additional 24 weeks.

Preliminary Results from the Escalation phase: 22 patients have been enrolled to date: Cohort (C) 1: 4 patients; C 2: 3 pts; C3: 7 pts; C 4: 7 pts; C 5: 1pt, ongoing. Median age 67 y/o; male 50%; all ECOG PS0-1 (27.3/72.7%); non squamous 15 (68%), squamous 7 (32%); locally advanced 4 (18%), metastatic 18 (82%); PD-L1 expression: positive 12 pts (52%), negative 10 pts (48%); prior lines of therapy - 1 line: 10 pts (45.5%), 2 lines:12 (54.5%). Previous treatment with PD-1/PD-L1 inhibitors: 18 pts (9 as single agent, 9 in combination). Median treatment duration 11.5 weeks (1 to 38). Eighteen patients discontinued DV281: adverse event 2, PD 14, other 2. Safety profile of DV281 alone and combined with nivolumab with a median number of 5 doses (1.0 to 18.0): grade 1/ 2 chills (18%), fatigue (13.6%), flu-like symptoms (4.5%), diarrhea (13.6%) and rash (13.6%); no grade ≥3 DV281/nivolumab treatment related AE; no immune-related AEs. Pharmacodynamic (PD) assessment (IFN-induced genes) shows target engagement in all dose cohorts, with every patient showing evidence of target engagement in cohorts 3 and 4. A dose dependent increase in PD activity appears to begin to plateau at the 15 mg dose.

Conclusions: In this population of heavily pretreated patients, DV281 in monotherapy and in combination with nivolumab was well tolerated. Target engagement was observed at all dose levels. The expansion phase will use a modified dosing schedule, evaluating several groups of patients: non squamous resistant to PD-1/PD-L1 or to EGFR inhibitors; squamous experienced or naïve to anti PD-1/PD-L1.

Citation Format: Edward Garon, Alexander I. Spira, Melissa Johnson, Lyudmila Bazhenova, Joseph Leach, Albert Candia, Robert Coffman, Mary Janatpour, Erick Gamelin, Robert Janssen, Laura Q. Chow. Phase Ib/II, open label, multicenter study of inhaled DV281, a Toll-like receptor 9 agonist, in combination with nivolumab in patients with advanced or metastatic non small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT224.

Phase 1b/2, open label, multicenter, study of the combination of SD-101 and pembrolizumab in patients with advanced melanoma who are naïve to anti-PD-1 therapy

9534

Background: SD-101 is a synthetic CpG TLR9 agonist. Pembrolizumab is a PD-1 inhibitor. SYNERGY-001/KEYNOTE-184 assesses the safety and preliminary efficacy of the combination of SD-101 and pembrolizumab in patients naïve to anti-PD-1/L1 therapy with unresectable stage IIIC-IV melanoma. Methods: SD-101 was evaluated as 2 mg/lesion injected into 1 to 4 lesions and 8 mg/lesion in 1 lesion as 4 weekly doses followed by 7 doses Q3W. Pembrolizumab was administered as 200 mg IV Q3W. CT scans were performed every 9 weeks. Responses were assessed per investigator using RECIST v1.1. Responses and post-hoc Kaplan-Meier analyses of PFS in the ITT population were compared for patients who received 2 mg/lesion with 8 mg/lesion. Results: 86 patients (2 mg: N = 45; 8 mg: N = 41) have been enrolled with similar baseline characteristics: median age = 66 years; male = 67%; ECOG stage 0 = 67%; disease stage: IIIC = 21%; IVM1a/b = 50%; IVM1c = 28%; LDH ≤ ULN = 71%; treatment naïve = 73%. Median follow up to date is 8.1 months in 2 mg group and 8.3 months in 8 mg group. SD-101 safety profile comprises flu-like symptoms with most frequent grade ≥3 SD-101-related AEs of headache (7%), fatigue (7%), malaise (5%), myalgia (4%), and chills (4%). Immune-related AEs were reported in 19%. ORR in 2 mg group = 71% (95% CI: 57, 82) (CR: 13%) and in 8 mg group = 49% (95% CI: 33, 65) (CR: 7%) with responses in both injected and non-injected lesions, including visceral. DOR = not reached (NR) in either group. ORR by baseline PD-L1 expression in 62 patients, 53% of whom were PD-L1 positive: 2 mg = 80%/79% (PD-L1 positive/negative); 8 mg = 62%/40% (PD-L1 positive/negative). PFS was higher in 2 mg group with median PFS in 2 mg = NR (95% CI: Not estimable [NE], NE) and in 8 mg = 10.4 months (95% CI: 4.2, NE), HR = 0.45 (95% CI: 0.21, 0.98), p = 0.036. 6 month PFS rate in 2 mg = 81% and in 8 mg = 60%. 6 month OS rate in 2 mg = 98% and in 8 mg = 92%. Conclusions: The TLR9 innate immune stimulant, SD-101, in combination with pembrolizumab has been well-tolerated, and is showing promising high response rates and PFS, regardless of PD-L1 expression, particularly in patients who received 2 mg SD-101. Clinical trial information: NCT02521870.

Phase 1b/2, open label, multicenter, study of the combination of SD-101 and pembrolizumab in patients with advanced/metastatic melanoma resistant to anti-PD-1/PD-L1 therapy

9555

Background: SD-101 is a synthetic CpG-ODN agonist of TLR9 that stimulates dendritic cells to release IFN-alpha and mature into antigen presenting cells - activating T cell anti-tumor responses. Pembrolizumab has demonstrated activity in melanoma. SYNERGY-001/KEYNOTE-184 study assesses the safety and preliminary efficacy of the combination of intratumoral SD-101 and intravenous pembrolizumab in PD1/PDL 1 resistant unresectable stage IIIC- IV melanoma. A prior phase 2 study with SD-101 at 8 mg per injection resulted in a 21.4% ORR in this population (Abstract 3781, ESMO 2018). We report preliminary data in this ongoing phase 2 trial evaluating efficacy at a lower SD-101 dose of 2 mg per injection. Methods: PD1/PDL 1 resistant melanoma patients received 2 mg of SD-101 intratumorally per lesion in 1-4 lesions (weekly x 4 doses followed by Q3W x 7). Pembrolizumab was administered at a dose of 200 mg intravenously Q3W. Scans were performed Q9W. Responses were assessed per RECIST v1.1. Results: 23 patients have been enrolled with baseline characteristics: median age 65 years; male: 77%; stage at screening: IIIC = 26%; IV = 57%, unknown = 17%; LDH > ULN: 36%. Lines of prior therapy: 1: 52%; 2: 22%; > 2: 26%. Prior anti CTL-A4 therapy: 39%. Best overall response on prior antiPD-1/PD-L1: PD: 88%, PR/CR: 8%, SD: 4%. Safety: Grade ≥3 treatment-related AEs: pneumonia and constipation (8%). No immune-related AEs reported. 2 non-treatment related SAEs reported from 2 patients: pneumonia and intussusception. 4 patients discontinued treatment early: 1 post SAE, per patient’s request, 3 due to PD. 1 patient died due to malignant pleural effusion after 1 dose of SD 101 and Pembrolizumab. No treatment related deaths. Efficacy: Mean duration on treatment: 39 days (1 - 169). mITT population: six patients at time of first CT scan at day 64: PR: 1, SD: 1, PD:3; non-evaluable: 1. 17 patients on study have not yet had first CT scan. Conclusions: The TLR9 innate immune stimulant, SD-101, in combination with pembrolizumab is well tolerated. Mature efficacy data, with additional first and second follow-up CT scans, will be presented at the meeting. Clinical trial information: NCT02521870.

Phase 1b/2, open label, multicenter study of intratumoral SD-101 in combination with pembrolizumab in anti-PD-1 treatment naïve patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC)

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Background: SD-101, a synthetic CpG-ODN agonist of TLR9, stimulates dendritic cells to release IFN-alpha and mature into antigen presenting cells - activating T cell anti-tumor responses. Pembrolizumab has demonstrated activity in HNSCC. Study DV3-MEL-01 (NCT02521870) assesses safety and efficacy of SD-101 in combination with pembrolizumab in patients with recurrent/metastatic HNSCC. We have previously reported a 27.3% ORR in 22 patients receiving 8 mg SD-101/injection in the modified ITT after at least 2 CT scans due to late responses (Abstract 3560, ESMO 2018). Higher efficacy at a lower SD-101 dose, 2 mg/injection, has been reported in advanced melanoma patients (LBA 45, ESMO 2018). Consequently, this dose is now being assessed in HNSCC. We report preliminary data with the 2 mg/injection dose in 23 patients in mITT at the first CT scan. Methods: Anti-PD-1/PD-L1 naïve patients received 2 mg SD-101 intratumorally in 1 - 4 lesions (weekly x 4 doses then Q3W x 7 doses). Pembrolizumab is was administered IV at 200 mg Q3W. Responses were assessed per RECIST v1.1. Results: 28 patients enrolled: median age 63 y/o, male 68%; ECOG PS 0-1 (18%/82%); mean prior lines of systemic therapy 1 (0-3); mean treatment duration 70 days (1-253). Primary tumors: 19 (68%) oropharyngeal; 3 (10%) laryngeal; 2 (7%) hypopharyngeal; 4 (14%) unknown. Mean number of target lesions: 1.82 (1 to 5). HPV status: 7 (25%) +, 9 (32%) -, 12 (43%) unknown. 18 (64 %) discontinued treatment: 12 (42%) due to PD, 4 (16%) deaths, 1 (3%) consent withdrawn, 1 (3%) went to hospice. Mean follow up 2.70 months. Safety: 16 non-treatment-related SAEs in 9 patients. 2 treatment-related Grade ≥3 AEs: sepsis (4%) and lymphopenia (4% ). No treatment-related deaths. Efficacy: 23 patients in the mITT population with first CT scan at day 64: ORR: CR: 2, PR: 3 (22%); SD: 6 (26%), PD: 7 (30%), non-evaluable: 5 (22%). Disease control rate (48%). 5 patients on study have not had a CT scan. Conclusions: SD-101 with Pembrolizumab shows early promising data and is well tolerated. Additional follow-up scans from both dose cohorts are being evaluated and will be presented. Clinical trial information: NCT02521870.

2287. Recently Approved HEPLISAV-B(R) [Hepatitis B Vaccine (Recombinant), Adjuvanted] Shows a Higher Proportion of Subjects Achieving Seroprotection With a More Consistent Immune Response Compared With Engerix-B(R) [Hepatitis B Vaccine (Recombinant)] in Three Comparative Trials

Background

HEPLISAV-B^® [hepatitis B vaccine (recombinant), adjuvanted] uses a cytidine phospho-guanosine (CpG) oligonucleotide or “1018,” a Toll-like receptor 9 agonist, as an adjuvant. Engerix-B^® [hepatitis B vaccine (recombinant)], as well as other hepatitis B vaccines, use alum. HEPLISAV-B, a 2-dose vaccine given at Weeks 0 and 4, was recently approved for use in adults ≥18 years for the prevention of hepatitis B. Approval of HEPLISAV-B was based on three pivotal phase 3 noninferiority trials, comparing it with Engerix-B, a 3-dose vaccine given at Day 0, Day 30, and 6 months. Immunogenicity and safety results for these trials, HBV-10, HBV-16 and HBV-23, have been published previously; the safety of HEPLISAV-B was generally similar to Engerix-B.

Methods

The 3 randomized trials were observer-blinded and collectively included subjects aged 18–70 years. Immunogenicity analysis based on antibody against hepatitis B surface antigen (anti-HBs) levels were based on the per-protocol analysis. Presented here are reverse cumulative frequency plots of anti-HBs serum concentrations for the 3 trials.

Results

Across the trials, reverse cumulative frequency plots of anti-HBs concentrations showed a higher proportion (>90%) of HEPLISAV-B subjects developed a seroprotective antibody level (anti-HBs levels ≥10 mIU/mL) compared with Engerix-B subjects (80% to ~90%). A higher proportion of HEPLISAV-B subjects had anti-HBs levels between 10 mIU/mL and 1,000 mIU/mL. While a higher proportion of Engerix-B subjects had anti-HBs levels >1,000 mIU/mL, a significantly higher proportion of Engerix-B subjects did not develop seroprotective antibody levels. The response curves indicate a more consistent immune response with a higher percentage of subjects achieving seroprotection with less variability for HEPLISAV-B compared with Engerix-B, which showed a more variable response and fewer subjects achieving seroprotection.

Conclusion

HEPLISAV-B, using a CpG adjuvant, results in a higher percentage of persons achieving seroprotection and produces a more uniform and consistent induction of protective antibody levels than Engerix-B, an alum-adjuvanted vaccine.

Disclosures

R. N. Hyer, Dynavax Technologies Corporation: Employee and Shareholder, Salary and Stock options. R. Janssen, Dynavax Technologies Corporation: Employee and Shareholder, Salary and Stock options.

In Situ Vaccination with a TLR9 Agonist and Local Low-Dose Radiation Induces Systemic Responses in Untreated Indolent Lymphoma

This multicenter phase I/II clinical trial evaluated intratumoral SD-101, a TLR9 agonist, and low-dose radiation in patients with untreated indolent lymphoma. Twenty-nine enrolled patients received 4 Gy of radiation followed by 5 weekly intratumoral injections of SD-101 at a single tumor site. No treatment-related grade 4 or serious adverse events occurred. Nearly all patients had tumor reduction at their treated site. More importantly, 24 patients had tumor reduction at their nontreated sites, with 5 patients achieving a partial response and one achieving a complete response. Treatment-related increases of CD8+ and CD4+ effector T cells and decreases of T follicular helper and T regulatory cells (Treg) were observed in the tumor microenvironment. Low pretreatment levels of CD4+ Tregs, proliferating CD8+ T cells, and Granzyme B+ CD8+ T cells were associated with favorable outcomes. Intratumoral SD-101 in combination with low-dose radiation is well tolerated and results in regression of both treated and untreated sites of disease.Significance: In situ vaccination with the TLR9 agonist SD-101, along with low-dose radiation, was safe and induced systemic responses in patients with indolent lymphoma. Low levels of CD4+ Tregs, proliferating CD8+ T cells, and Granzyme B+ CD8+ T cells in the tumor microenvironment predicted favorable response to treatment. Cancer Discov; 8(10); 1258-69. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 1195.