Abstract LB008: Characterization of immune correlates of clinical activity for Nous-209, an off-the-shelf immunotherapy, with pembrolizumab for treatment of tumors characterized by microsatellite instability (MSI)

Tumors with microsatellite instability (MSI) are caused by a deficiency in DNA mismatch repair (dMMR) system that leads to the accumulation of mutations within microsatellite regions. These types of mutations can determine a shift of the translational reading frame, generating Frame Shifted Peptides (FSPs). FSPs are tumor-specific neoantigens. Nous-209 is an off-the-shelf vaccine encoding 209 FSPs shared across dMMR/MSI tumors (Leoni et al., Cancer Res, 2020). The combination of the Nous-209 genetic polyvalent cancer vaccine and pembrolizumab has been demonstrated to be safe, highly immunogenic, with promising early signs of clinical efficacy in 12 patients with 7 durable confirmed PRs, 2 durable SDs and 3 PDs observed (Overman et al., SITC Nov 13, 2021 Poster number: 410). Here, we explore immune correlates potentially associated with the clinical outcome with the aim to address the Nous-209 contribution to the activity of pembrolizumab in this patient population. Several immunological analyses were performed on biological samples collected before and after treatment with Nous-209. Analyses were performed on paired blood and tumor biopsy samples. In periphery, vaccine immunogenicity was demonstrated by ex-vivo interferon-gamma ELISpot assay in 67% of subjects in dose level 1 (n=3), and 100% (n=7) of patients in dose level 2 with a mean of ≈1,500 IFN-γ SFCs/million PBMCs at the peak of the immune response. In 3 patients with partial response whose pre/post tumor biopsies were available, the intratumoral TCR repertoire was expanded and diversified post treatment with Nous-209. Moreover, in one out of these three patients it was possible to track vaccine-induced neoantigen specific TCR in the tumor biopsy post Nous-209 treatment. Overall, these results indicate that neoantigen specific CD8+ T cells, induced by Nous-209, expand and diversify upon treatment, and successfully traffic to and infiltrate the tumor microenvironment to exert anti-tumor activity.

Citation Format: Anna Morena D'Alise, Guido Leoni, Francesca Langone, Elisa Micarelli, Gabriella Cotugno, Michael James Overman, Marwan Fakih, Dung Le, Théa Faivre, Elisa Scarselli. Characterization of immune correlates of clinical activity for Nous-209, an off-the-shelf immunotherapy, with pembrolizumab for treatment of tumors characterized by microsatellite instability (MSI) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB008.

First clinical and immunogenicity results including all subjects enrolled in a phase I study of Nous-209, an off-the-shelf immunotherapy, with pembrolizumab, for the treatment of tumors with a deficiency in mismatch repair/microsatellite instability (dMMR/MSI)

2515

Background: Defective DNA mismatch repair (dMMR) leads to high levels of microsatellite-instability (MSI-H) and insertions or deletions in coding regions, triggering the generation of tumor-specific frameshift peptides (FSPs). We selected 209 shared FSPs among subjects with dMMR/MSI-H cancers, to generate an off-the-shelf vaccine for the treatment of dMMR/MSI-H tumors. Those FSPs were cloned into four proprietary Great Apes Adenoviral (GAd) and four Modified Vaccinia Ankara (MVA) vectors to create a polyvalent viral vectored vaccine named Nous-209 [Leoni, G. et al. Cancer Res, 2020. 80(18): p. 3972-3982.]. Methods: This phase 1 first in human (FIH) study ( NCT04041310 ) evaluates safety and tolerability of two dose levels of the Nous-209 in combination with pembrolizumab, assesses immunogenicity and detects preliminary evidence of anti-tumor activity. Nous-209 is administered intramuscularly, concomitantly with pembrolizumab: one prime (GAd-209-FSP) at the 2nd pembrolizumab infusion and three boosters (MVA-209-FSP) at subsequent infusions each 3 weeks apart. The study is composed of two sequential cohorts i.e. dose escalation and dose expansion. Results: All evaluable subjects with 1st- or 2nd-line metastatic dMMR/MSI-H colorectal (CRC), gastric or gastroesophageal junction (GEJ) cancers enrolled in this phase I (n = 20) were evaluated as of February 03, 2022. Three subjects enrolled in dose level (DL) 1 (2 CRC and 1 GEJ cancer) showed durable confirmed partial responses (PRs). In DL 2 (12 CRC and 5 gastric cancers), 7 subjects had PRs, 6 had stable disease (SD) and 4 had progressive disease (PD) as best response. Most progressors progressed at the 1st CT and none of the responders have progressed. The median follow-up for subjects in DL1 is 24.7 months (22.3-26.7), and 7.6 months (0.9-19.4) in DL 2. The median progression free survival (PFS) and median duration of response (DoR) have not been reached. No dose limiting toxicities (DLTs) were observed. Vaccine immunogenicity was demonstrated in periphery by ex-vivo interferon-gamma ELISpot in 67% of subjects in DL 1, and 82% of subjects with evaluable samples in DL 2. The intratumoral TCR repertoire on pre/post tumor biopsies was analyzed in 3 evaluable subjects with PR and in 1 with PD: expansion and diversification of T cells post treatment with Nous-209 was noted only for the former. Vaccine-reactive TCR clones infiltrating the tumor biopsy post treatment were found in the only subject evaluated to date, with a long-term response. Conclusions: The combination of the Nous-209 and pembrolizumab is safe and well tolerated, and shows signs of clinical efficacy. Nous-209 elicits a neoantigen-specific T cell response expanding within the tumor, possibly contributing to the clinical outcome. Clinical trial information: NCT04041310.

Phase lb combination trial of a MEK inhibitor, pimasertib (MSC1936369B), and a PI3K/mTOR inhibitor, SAR245409, in patients with locally advanced or metastatic solid tumors

TPS3118

Background: The PI3K/mTOR and MAPK signaling pathways are frequently aberrantly activated in tumors and interact to promote growth and resistance to treatment. Simultaneous inhibition of both pathways may enhance antitumor activity. This trial investigates the combination of pimasertib, a highly selective MEK1/2 inhibitor, and SAR245409, a dual PI3K/mTOR inhibitor (ClinicalTrials.gov NCT01390818). Maximum tolerated dose (MTD) when administered once daily (qd) as a single agent to solid tumor patients (pts) is 90 mg for both compounds. Methods: Pts with advanced solid tumors characterized by frequent alterations of the MAPK or PI3K/mTOR pathways (pancreatic, thyroid, colorectal, non-small cell lung, endometrial, renal, breast, ovarian and melanoma) and/or with identified alterations in genes activating these pathways, adequate performance status and organ function, and no retinal disease are eligible for entry. The primary objective of the trial is to determine the MTD of the combination therapy. Secondary objectives include: safety, pharmacokinetics (PK), pharmacodynamics (PD), biomarker identification and antitumor efficacy (response rate via RECIST v1.1). Both compounds are dosed together qd continuously in 21 day cycles. The study uses a classical 3 + 3 design, with modified Fibonacci (decreasing increments) dose escalation based on occurrence of dose-limiting toxicities (DLTs). In parallel with dose escalation, more pts may be enrolled in already tested lower dose level (DL) cohorts to further evaluate PK, PD, safety and antitumor activity. After MTD confirmation, additional pts may be enrolled in up to 4 disease-specific cohorts based on scientific rationale, and observed preclinical and clinical activity signals. As of January 25th 2012, 20 pts have been treated. No DLTs have been reported.

Detection of domain-wall position and magnetization reversal in nanostructures using the magnon contribution to the resistivity

We show that magnetization reversal detection can be achieved at room temperature using the contribution of magnons to resistivity, in 50 nm wide nanowires with either perpendicular anisotropy (FePt) or in-plane magnetization (NiFe). Even though these nanowires are made from single layers, simple magnetoresistance measurements can be used to measure switching fields, or to detect the position of a domain wall along a nanowire. Surprisingly, in NiFe nanowires, and for applied fields nearly parallel to the wire, the magnon contribution is found to dominate the classical anisotropic magnetoresistance.

[Sleep and aging]

A COMMON DISORDER: Sleep is one of the most often altered functions in elderly people. Obviously, insomnia is one of the main complain, inducing benzodiazepine (BSD) abuse, but we must keep in mind that sleep apnoea syndrome (SAS) and restless legs syndrome (RLS) are also frequent in this group of age. After exclusion of the various age-related conditions that could induce sleep disorders, we must focalise on primary and secondary sleep disorders. As an introduction, methods of sleep analysis are described and qualitative and quantitative sleep variables are given. PHYSIOLOGICAL SLEEP: Comparing the sleep of elderly people to the one of young adult give us the opportunity to define the limits of the physiological sleep aging. It seems that the main age-induced sleep disturbances are problems to maintain sleep and chronobiological disorganisation of the sleep-wake rhythm, both responsible for insomnia complains. It is important to note that SAS and RLS prevalence are correlated with age. Also crucial is the complex association between sleep, depression and dementia. These interactions are addressed from a diagnostic and a therapeutic point of view.

THERAPEUTIC APPROACH

Lastly, concerning insomnia we emphasise the importance of therapeutic alternative to BZD, responsible for addictions and cognitive impairment, mainly behavioural and chronotherapeutic methods (phototherapy, melatonin). For clinicians, it is recommended to respect the individual rhythms of each elderly patient and to prefer nonpharmacological methods.

Valpromide increases amplitude of heart rate circadian rhythm in remitted bipolar and unipolar disorders. A placebo-controlled study

The aim of this study was to investigate for the effects of valpromide on heart rate circadian rhythm in remitted recurrent unipolar and bipolar disorders (DSM-III-R). It consisted of a comparative, randomized, double-blind, repeated cross-over study of valpromide versus placebo over four four-week periods. The primary evaluation criteria was heart rate (HR). Secondary criteria comprised motor activity (MA) and the Bech and Rafaelsen mania assessment scale, Horne and Ostberg questionnaire, Montgomery and Asberg depression rating scale, Spiegel questionnaire, a sleep diary, and Clinical Global Impression. Fifteen patients were included, giving 60 one-month periods (30 valpromide periods and 30 placebo periods). Cosinor analysis of HR and MA data revealed a difference in amplitude (P = 0.037, analysis of variance, one-tailed test). The clinical sleep study shows that the duration of sleep was greater with valpromide than with placebo (P = 0.007, one-tailed test). Similarly, evaluation of the quality of sleep by patients themselves showed valpromide to be superior to placebo (P = 0.045, one-tailed test). The results of analysis of the Spiegel questionnaire also confirm the superiority of valpromide over placebo. Safety and compliance were comparable for the active drug and the placebo. In conclusion, the relatively small sample size requires cautious interpretation of this study. Nevertheless, these initial results show a definite effect of valpromide on a biological rhythm that leads one to suppose that it may be effective through a 'synchronizing' effect.