Peng, Kah Whye

Abstract Background: Bladder cancer is a leading cause of cancer death in the United States1. The histology in > 90% of cases is urothelial carcinoma (UC). Tumors may present either as non-muscle-invasive (NMIBC) or muscle-invasive disease (MIBC). Current standard of care for patients with high risk NMIBC includes transurethral resection of bladder tumor (TURBT) followed by intravesical immunotherapy with Bacillus Calmette-Guerin (BCG)2. Meanwhile, patients with BCG unresponsive NMIBC or MIBC are recommended to undergo radical cystectomy (RC), which adversely impacts quality of life and is associated with significant morbidity3. MV-NIS is an investigational oncolytic measles virus with an excellent clinical safety profile4. This ongoing phase I clinical study is designed to test the safety, efficacy and identify the recommended phase 2 dose (RP2D) of intravesical MV-NIS in patients with NMIBC or MIBC who are scheduled for RC and not eligible for neoadjuvant chemotherapy. Methods: Bladder UC patients were evaluated for eligibility and provided informed consent prior to enrolling. To date 8 patients have been enrolled: 4 to the single dose safety cohort, and 4 to the multi-dose expansion cohort. Patients were administered intravesical ~1x109 TCID50 MV-NIS once at least 1 week prior to RC (safety cohort), or twice at 4 and 2 weeks prior to RC (expansion cohort). Patients were closely monitored during the 2-hour instillation period. Tumor specimens from the pre-treatment TURBT and post-treatment RC were analyzed to determine pre- and post-treatment pathological stage and evaluate tumor killing and immune cell infiltrate. Results: Intravesical MV-NIS treatment was well tolerated in all patients. Only a single Adverse Event (AE) attributable to MV-NIS treatment (Grade 1 hematuria). AEs Grade>2 were related to post-surgical complications. Tumor downstaging was observed in 4 of 8 patients. Among 4 patients in the expansion cohort, 2 had no residual disease (pT0). Central assessment of RC tissues showed significant inflammatory infiltrate in all treated bladder specimens. Detailed analyses are ongoing to characterize MV infection and immune infiltrate in bladder tissue. Conclusions: The higher-than-expected rate of tumor downstaging and pT0 pathology, paired with the significant immune infiltrate observed in post-treatment bladder tissue, provide compelling evidence that intravesical MV-NIS has clinical activity against UC. These results support the use of two doses of ~1x109 TCID50 as the RP2D in future clinical studies for BCG unresponsive NMIBC or MIBC patients. MV-NIS induced inflammation may act synergistically with checkpoint blockade therapies. References 1. Siegel, R.L., Miller, K.D. & Jemal, A. CA Cancer J Clin 69, 7-34 (2019). 2. Knowles, M.A. & Hurst, C.D. Nature reviews. Cancer 15, 25-41 (2015). 3. Zakaria, A.S., et al. Can Urol Assoc J 8, 259-267 (2014). 4. Galanis, E., et al. Cancer research 75, 22-30 (2015). Citation Format: Tanner S. Miest, Bradley Leibovich, Stephen Bardot, Paul R. Young, Stephen A. Boorjian, Mark Gonzalgo, Loren Herrera-Hernandez, Matthew K. Tollefson, Jeffrey Karnes, Paige Nichols, Tessa Kroeninger, Rachel Graham, Carole Lahana, Monica Reckner, Alysha Newsom, Nandakumar Packiriswamy, Janice Anoka, Kah Whye Peng, Erol Wiegert, Alice Bexon, Shruthi Naik. Safety and efficacy of neoadjuvant intravesical oncolytic MV-NIS in patients with urothelial carcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P190.

Since its emergence at the end of 2019, SARS-CoV-2, the causative agent of COVID-19, has caused over 100 million infections and 2.4 million deaths worldwide. Recently, countries have begun administering approved COVID-19 vaccines, which elicit strong immune responses and prevent disease in most vaccinated individuals.

2500 Background: Oncolytic virotherapy is a novel immunomodulatory therapeutic approach for relapsed refractory hematologic malignancies. The Indiana strain of Vesicular Stomatitis Virus was engineered to encode interferon beta (IFNβ) and sodium iodine symporter (NIS) to produce VSV-IFNβ-NIS. Virally encoded IFNβ serves as an index of viral proliferation and enhances host anti-tumor immunity. NIS was inserted to noninvasively assess viral biodistribution using SPECT/PET imaging. We present the results of the phase 1 clinical trial NCT03017820 of systemic administration of VSV-IFNβ-NIS among patients (pts) with relapsed refractory Multiple Myeloma (MM), T cell Lymphoma (TCL) and Acute myeloid Leukemia (AML). Methods: VSV-IFNβ-NIS was administered at 5x109 TCID50 (50% tissue culture infectious dose) dose level 1 to dose level 4, 1.7x1011 TCID50. The primary objective was to determine the maximum tolerated dose of VSV-IFNβ-NIS as a single agent. Secondary objectives were determination of safety profile and preliminary efficacy of VSV-IFNβ-NIS. Correlative objectives included monitoring viremia and virus shedding. Adverse events (AEs) are reported based on CTCAE V4; cytokine release syndrome (CRS) grading was based on Lee (Blood 2014) criteria. Results: 15 pts received VSV-IFNβ-NIS: MM (7), TCL(7) and AML(1); 3 pts were treated at each dose level (DL) 1 through 3 (respectively 0.05, 0.17, and 0.5 x 1011 TCID50), & 6 pts were treated at dose level 4 (1.7x1011 TCID50). There were no dose limiting toxicities. The most frequent grades 3 & 4 AEs were hematologic: lymphopenia (46.6 & 26.6%), neutropenia (13.3% & 6.7%). CRS grades 1 (6.7%) and 2 (46.6%) were the non-hematologic AEs of note; mostly at DL 4. Only 1 pt required transient pressor support. Responses were seen in pts with T cell lymphoma. At DL2, there was a partial response (PR) lasting 3 months in a pt, post 12 prior lines of therapy. At DL4 there was a 6 month PR in a pt with PTCL and another pt with cutaneous relapse of PTCL who enjoys an ongoing CR, more than 1 year post VSV infusion; both pts received 5 prior lines of therapy. Viremia was detected in all pts at the end of infusion only up to 72 hrs post infusion; no infectious virus was recovered in buccal swabs or urine. Neutralizing anti-VSV antibodies were present by day 29. IFN levels were detectable within 30 mins of infusion, peaking between 4 & 48 hrs. TCL pts mounted higher hIFNβ levels within 48 hrs; the pt with CR mounted peak hIFNβ response of 18213.3pg/ml at 48 hrs post infusion, 15-fold higher than any other pt. Conclusions: VSV-IFNβ-NIS can be safely administered by IV infusion among heavily pretreated pts with hematologic malignancies. VSV-IFNβ-NIS as a single agent appears to be most effective at DL4 among patients with TCL, with an ongoing CR in a patient at DL4 more than 1 year post administration. Future trials of combination strategies with immune-modulatory drugs are currently being planned. Clinical trial information: NCT03017820.

Abstract Measles viruses (MV) are rapidly inactivated by anti-measles neutralizing antibodies, which has limited their clinical performance as oncolytic agents. Here, by substituting the H and F surface glycoproteins of MV with those from the homologous canine distemper virus (CDV) and engineering the CDV H attachment protein to target EGFR or CD38, we generated a fully retargeted MV capable of resisting neutralization by measles-immune human serum. The resultant recombinant MVs encoding retargeted CDV envelope glycoproteins had similar growth kinetics as the control MV, showed the expected engineered receptor specificities for cell entry, intercellular fusion, and target cell killing, and were blind to native CDV receptors. In contrast to the control MV, recombinant MVs incorporating CDV F and H glycoproteins retained full infectivity when exposed to high concentrations of pooled measles-immune human serum. Comparing viruses bearing MV or CDV glycoproteins in the SKOV3ip.1 model, only the virus bearing an EGFR-retargeted CDV envelope glycoprotein complex was capable of limiting tumor growth and extending the survival in measles immune mice. MV, “stealthed” and retargeted using engineered CDV surface glycoproteins, may be a promising platform to advance for systemic cancer therapy in measles immune patients.

TPS3172 Background: Bladder cancer is a leading cause of cancer death in the United States. Over 90% of bladder cancer cases are urothelial carcinomas (UC) that may present as a non-muscle-invasive (NMIBC) or muscle-invasive disease (MIBC). Standard of care for NMIBC includes transurethral resection of bladder tumor (TURBT), intravesical chemotherapy and immunotherapy with Bacillus Calmette-Guerin (BCG). Patients (pts) with high-grade BCG-refractory NMIBC or MIBC undergo RC, which involves complete bladder removal and pelvic lymphadenectomy. RC severely impacts quality of life with significant morbidity. Oncolytic viruses are showing promise in UC, and MV-NIS has proven efficacy in other tumor types. MV-NIS is an investigational oncolytic measles virus with an excellent safety profile, irrespective of route of administration (n > 100). MV-NIS-related adverse events are limited to infusion reactions and transient CBC changes, and little local toxicity is anticipated with intravesical therapy. Clinical efficacy of this oncolytic may be related to absence of measles immunity. Based on this, the clinical strategy for MV-NIS is focused on targeting immune-privileged sites via intra-tumoral or intravesical routes, alone or in combination with checkpoint inhibitors. We hypothesize that intravesical therapy with oncolytic MV-NIS can improve clinical outcomes for (a) BCG refractory NMIBC pts to avoid or delay the need for RC; and (b) MIBC pts undergoing RC. Methods: This study is enrolling pts undergoing RC who are ineligible to receive neoadjuvant chemotherapy. The trial has 2 stages to (a) determine the safety and tolerability of intravesical MV-NIS, and (b) assess preliminary efficacy. Part (a) includes 4-24 pts in a timing cohort with doses administered at increasing durations (1-4 weeks) prior to RC to establish safety of a single MV-NIS dose. Part (b) includes an expansion cohort (n = 12) to evaluate the safety and efficacy of 2 intravesical doses of MV-NIS at 2-week intervals prior to RC. Safety is assessed using NCI-CTCAE V5 and Clavien-Dindo grading of operative complications. The efficacy endpoint is pathologic stage at time of RC (pT0 rate), which can be compared to pre-study TURBT stage. Additional exploratory studies include PK and PD analyses in urine, blood and tumor. Enrollment is ongoing at 2 Mayo Clinic sites (Rochester, MN and Jacksonville, FL) and the study has now progressed from the timing cohort into the expansion cohort. Clinical trial information: NCT03171493 .

TPS3161 Background: VV1 is an oncolytic vesicular stomatitis virus engineered to express human IFNβ to enhance cellular anti-tumor immune responses and tumor selectivity, and the human sodium iodide symporter (NIS) for virus tracking by SPECT imaging. Cancer cells are often hyporesponsive to IFNβ, enabling the efficient spread of VV1 and resulting in increased oncolysis. Differently from other oncolytic viruses, VV1 is suitable for both intra-tumoral (IT) and/or intra-venous (IV) administration. Despite considerable anti-tumor activity with checkpoint inhibitors (CPI) among some malignancies, long term survival and overall cures remain elusive. Prior Ph 1 studies have shown significant anti-tumor activity among several malignancies when VV1 was administered either as monotherapy or in combination with a CPI, despite progression on prior CPI monotherapy. Furthermore, pre- and post-treatment biopsy evaluations after VV1 treatment have demonstrated T cell infiltration and inflammation in both IT injected and non-injected lesions. Among IV treated patients (pts), IFNβ was detectable in the serum correlating with viral replication, making it an effective biomarker. C is a high-affinity potent human IgG4 anti-PD-1 monoclonal antibody. Though approved for use in cutaneous squamous cell carcinoma, C has shown anti-tumor activity, similar to other CPI, in several other indications. Therefore, VV1 and C could be an attractive combination for the immunotherapy for several solid tumors. This study represents the first clinical evaluation of VV1 in combination with C in pts with advanced solid tumors. Methods: The Ph 2 Simon 2 stage five-arm study of IV administration VV1 in combination with IV C will enroll pts with advanced NSCLC, HCC, melanoma & endometrial cancer. Enrolled pts with NSCLC & melanoma will be recent CPI-progressors, whereas enrolled HCC & endometrial cancer will be CPI-naïve. The study’s objectives include assessment of preliminary anti-tumor activity, safety, & immuno-regulatory activity of the combination. Pts will receive IV VV1 once on D1 and IV C once every 3 weeks until confirmed disease progression or intolerable toxicity. Pts enrolled in one melanoma cohort will also receive IT VV1 administered to palpable lesions. Response will be assessed every 9 weeks per RECIST v1.1. The null hypothesis of each cohort’s ORR will be tested versus a one-sided alternative yielding a Type I error rate of 5% and power of 80%. Cohorts will be expanded based on signal of activity. Clinical trial information: NCT .

3090 Background: VV1 (Voyager V1) is derived from VSV, an RNA virus with low human seroprevalence, engineered to replicate selectively in and kill human cancer cells. In Part 1 of this study, we demonstrated the safety of intratumoral VV1 and dose-response, using serum IFNβ as a biomarker; we observed viral replication in tumor and concomitant lymphocyte/neutrophil trafficking (SITC 2018). 2 other studies suggested greater efficacy and higher IFNβ levels with IV administration. Longer infusion durations were reported to mitigate infusion reactions (IRRs) for another oncolytic. Methods: We studied 3 different infusion durations of VV1 monotherapy at the recommended phase 2 IV dose (1.7 x 1010 TCID50) in patients with advanced solid tumors. Endpoints included safety, preliminary anti-tumor activity, viral titers, IFNβ PD and shedding. Patients received IV VV1 once on D1 and were monitored for DLT over 21 days with efficacy assessments every 6 weeks. IRRs were classified using Lee 2014 criteria for CRS as either constitutional symptoms only (G1) or involving hypotension (G2). Results: 18 patients were treated at 30, 60 and 180-minute durations (n = 7, 5 and 6, respectively). No DLTs, deaths or G3-4 related IRR AEs were observed. Most pts were female (67%), white (100%), with ECOG PS 0 (61%) and median 4 lines of prior systemic therapy (range 1-14) for colorectal (CRC; 56%), squamous cell carcinoma (11%), pheochromocytoma (11%), sarcoma (11%) or other (11%) cancers. The table shows results (number of patients) by infusion duration. Conclusions: There was no difference in safety between the 3 infusion durations, while efficacy and PD markers suggested better anti-tumor effect with 30-minute infusion. VV1 is safe for caregivers, with no viral shedding. Part 3 of this study will now treat CRC patients with VV1 in combination with a checkpoint inhibitor (avelumab). A 5-arm phase 2 basket study in combination with cemiplimab is proceeding with 30-minute infusions. Clinical trial information: NCT02923466 . [Table: see text]

Abstract Targeting the B-cell receptor and phosphatidylinositol 3-kinase/mTOR signaling pathways has shown meaningful, but incomplete, antitumor activity in lymphoma. Glycogen synthase kinase 3 (GSK3) α and β are 2 homologous and functionally overlapping serine/threonine kinases that phosphorylate multiple protein substrates in several key signaling pathways. To date, no agent targeting GSK3 has been approved for lymphoma therapy. We show that lymphoma cells abundantly express GSK3α and GSK3β compared with normal B and T lymphocytes at the messenger RNA and protein levels. Utilizing a new GSK3 inhibitor 9-ING-41 and by genetic deletion of GSK3α and GSK3β genes using CRISPR/CAS9 knockout, GSK3 was demonstrated to be functionally important to lymphoma cell growth and proliferation. GSK3β binds to centrosomes and microtubules, and lymphoma cells treated with 9-ING-41 become arrested in mitotic prophase, supporting the notion that GSK3β is necessary for the progression of mitosis. By analyzing recently published RNA sequencing data on 234 diffuse large B-cell lymphoma patients, we found that higher expression of GSK3α or GSK3β correlates well with shorter overall survival. These data provide rationale for testing GSK3 inhibitors in lymphoma patient trials.

Abstract Introduction Voyager-V1TM is derived from VSV, a bullet-shaped negative sense RNA virus with very low human seroprevalence; it is engineered to selectively replicate in and kill human cancer cells. Voyager-V1 encodes the human IFNβ gene to boost antitumoral immune responses and the thyroidal sodium iodide symporter NIS gene to permit noninvasive imaging of virus spread. FIH studies are underway via both IV and IT routes. Here we report safety and preliminary correlative data from the FIH IT study. Methods and objectives This is a classical 3+3 phase 1 design, using escalating single IT viral doses from 3 x 106 to 3 x 109 TCID50 into one target lesion. The primary objective is safety and tolerability, monitored by committee. Other objectives include PK by RT-PCR for viral genomes, serum IFNβ levels, Tc-99m SPECT/CT imaging to monitor virus infection in injected lesions, peripheral blood immunophenotyping with 11-color flow cytometry for activation markers on T cells, T-regs, NK cells, and MDSCs, and serial biopsies to assess the tumor microenvironment (TME). IHC was performed on tumor biopsies for CD3, CD8, CD4, FoxP3, CD68, PD-1 and PDL-1 pre and post treatment in non-injected and injected lesions. CD45 staining is ongoing. Results Dose level 3 is ongoing (n=8+). No DLTs have been observed to date. Most patients were male (75%), white (100%), with ECOG PS1 (75%) and a median of >6 lines of prior systemic therapy. AEs (in 63% patients) reported as related to study drug were mild-moderate, short-lived, and consisted of G1 fever, chills, hot flashes, nausea, vomiting, hyperhidrosis and G2 fatigue. Most patients had some mild AEs (pain, bruising, subclinical pneumothorax) related to biopsy and IT injection procedures and one had an SAE related to biopsy (G2 pneumothorax). There was no difference in incidence, intensity or duration of related AEs between dose levels so far. In patients analyzed to date, at the first three dose levels of 3 x 106, 1 x 107 and 3 x 107 TCID50 (n=7), viremia and serum IFNβ were below levels of detection after IT injection. There is evidence in all patients of an increase in PD-1 expression on CD4 and CD8 T cells, suggesting T cell activation post- single virus injection. One patient at dose level 2 had increased CD4 and CD8 T cells in the peripheral blood. TME analysis revealed increased infiltration of CD3 and CD8 cells in tumors of some patients. In addition, there are changes in numbers of FoxP3 and CD68 positive cells in the injected lesions compared to the pre-treatment and non-injected lesion. Two patients at dose level 3, one with an injected adrenal metastasis of colorectal cancer and another with a chest wall lesion from a head of pancreas primary, have positive SPECT/CTs on days 3-15 showing viral replication in tumor plus concomitant lymphocyte/neutrophil trafficking in the periphery. Conclusions IT injection of a single dose of the novel oncolytic virotherapy Voyager-V1 has proven safe at doses up to 3 x 107 TCID50. There was evidence of T cell activation with increased PD-1 expression in peripheral blood lymphocytes after a single IT injection. Tumor biopsies indicate increased lymphocyte infiltration. Two patients at the highest dose tested show signs of viral replication in the injected lesion plus evidence of systemic impact on leukocyte populations. Citation Format: Steven Powell, Manish R. Patel, Jaime R. Merchan, Timothy P. Cripe, James Strauss, Rosa M. Diaz, Nandakumar Packiriswamy, Bethany A. Brunton, Deepak Upreti, Rehan Khan, Lukkana Suksanpaisan, Rianna Vandergaast, Stephen J. Russell, Alice S. Bexon, Kah Whye Peng. Preliminary correlative and clinical data from a first-in-human (FIH) study of the intratumoral (IT) oncolytic virotherapy, Voyager-V1, in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT051.