523 Preliminary clinical experience with XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report updated data on patients treated at the recommended expansion dose from an ongoing, multicenter, Phase 1, dose-escalation and -expansion study of intravenous XmAb20717 in patients with selected advanced solid tumors that progressed after treatment with all standard therapies or with no standard therapeutic options.

Methods

A maximum tolerated dose was not reached in dose escalation. XmAb20717 10 mg/kg every 2 weeks (Q2W) was selected as the expansion dose, based on consistent T-cell proliferation in peripheral blood indicative of dual PD-1/CTLA-4 checkpoint blockade, and response to treatment (RECIST[1.1]).1 Parallel expansion cohorts included ~20 patients each with melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), castration-resistant prostate cancer (CRPC), and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI). Patients treated with 10 mg/kg in dose escalation were pooled with expansion cohorts for analysis of clinical activity and safety.

Results

As of 9 June 2021, 110 patients, ranging in age from 39 to 89 years and 66.4% male, were treated, and 5 were continuing treatment. Patients had received a median of 4 prior systemic treatment regimens, including CI therapy for 64.5%. The objective response rate was 13.0% (10/77 patients evaluable for efficacy), including 1 complete response (melanoma [confirmed]) and 9 partial responses (confirmed: 1 melanoma, 2 RCC, 2 CRPC, 1 ovarian cancer; unconfirmed: 1 melanoma, 2 NSCLC). The CRPC responders (2/7 with RECIST-measurable disease) had confirmed PSA decreases ≥ 50% from baseline (to 0.02 and 0.3 ng/mL); neither had progression on bone scans. All responders had prior CI exposure, except those with CRPC. Robust CD4 and CD8 T-cell activation was seen. Low baseline tumoral expression of myeloid recruitment genes, including IL-8, was associated with clinical benefit. Grade ≥ 3 immunotherapy-related adverse events in ≥ 3 patients included rash (16.4%), transaminase elevations (9.1%), hyperglycemia (4.5%), acute kidney injury (3.6%), amylase and lipase increased (2.7%), and lipase increased (2.7%).

Conclusions

Preliminary data indicate 10 mg/kg XmAb20717 Q2W was associated with complete and partial responses in multiple tumor types and was generally well-tolerated in these heavily pretreated patients with advanced cancer. Changes in T-cell populations in the periphery and tumor are consistent with robust dual checkpoint blockade. These findings support further development of XmAb20717 in advanced solid tumors, including metastatic prostate cancer.

Trial Registration

NCT03517488

References

Shum E, Daud A, Reilley M, et al. Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors. JITC 2020;8(3):A247-8.

Ethics Approval

The study was approved by each institution’s IRB.

407 Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report preliminary data from an ongoing, multicenter, Phase 1 study investigating the safety/tolerability, pharmacokinetics/pharmacodynamics, and clinical activity (RECIST 1.1) of XmAb20717 in patients with selected advanced solid tumors.

Methods

A 3+3 dose-escalation design was used to establish a maximum tolerated (MTD)/recommended dose for evaluation in parallel expansion cohorts, including melanoma, renal cell carcinoma, non-small cell lung cancer (NSCLC), prostate cancer, and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI; n≤20 each). XmAb20717 was administered as an infusion on Days 1 and 15 of each 28-day cycle.

Results

As of 08Jul2020, 109 patients had been treated (table 1), and 30 were continuing treatment. In escalation, 6 dose levels (0.15–10.0 mg/kg) were evaluated (n=34); an MTD was not established. Expansion cohorts were initiated at 10 mg/kg (n=72), and a 15 mg/kg escalation cohort was added (n=3). T-cell proliferation was noted in peripheral blood at doses as low as 3 mg/kg and was highest at 10 mg/kg. At this dose, consistent proliferation of CD8+ and CD4+ T cells was observed, indicative of dual PD-1 and CTLA-4 checkpoint blockade (figure 1). Paired pre- and post-dosing biopsies showed increased intratumoral T-cell infiltration and IFN-response signatures following treatment. Grade 3/4 treatment-related adverse events (TRAEs) reported for ≥3 patients included rash (13%), transaminase elevations (7%), lipase increased (4% [2% with amylase increased]), and acute kidney injury (3%), all considered immune-related. There were 2 Grade 5 TRAEs: immune-mediated pancreatitis (in the presence of pancreatic metastases) and immune-mediated myocarditis (Grade 4) that contributed to respiratory failure. A complete response was reported as the best overall response for 1 patient (melanoma); partial responses were reported for 5 patients (2 melanoma, 2 NSCLC, 1 ovarian). The objective response rate was 13% overall and 21% at 10 mg/kg (6/46 and 6/29 evaluable patients, respectively). All responders had prior CI exposure. Responses were observed only at 10 mg/kg and, within the 10 mg/kg group, appeared to correlate with higher peak serum concentration and area under the curve.

Abstract 407 Table 1

Demographics and baseline characteristics

Abstract 407 Figure 1

Mean change from baseline in percentage of Ki67+ T–cell expression in peripheral blood during first two cycles of XmAb20717

Conclusions

XmAb20717 induced T-cell proliferation in peripheral blood consistent with dual-checkpoint blockade. Preliminary data indicate XmAb20717 was generally well-tolerated and associated with evidence of antitumor activity in CI-pretreated patients with various types of advanced solid tumors.

Trial Registration

NCT03517488

Ethics Approval

The study was approved by each institution’s IRB.

Immune modulation after Toca 511 and Toca FC treatment of colorectal cancer patients

186

Background: Toca 511 (vocimagene amiretrorepvec) is a cancer-selective, retroviral replicating vector encoding yeast cytosine deaminase that converts 5-fluorocytosine (5-FC) into 5-fluorouracil in the tumor microenvironment (TME). In animal models, Toca 511 and 5-FC kill dividing cancer and nearby immunosuppressive cells, leading to antitumor immune activity. A Phase 1 study of Toca 511 & Toca FC (extended-release 5-FC) in patients with recurrent high grade glioma revealed results consistent with this proposed mechanism. A Phase 3 trial is ongoing. Methods: Toca 6 (NCT02576665) is a Phase 1b, single-arm, multicenter study designed to investigate immunological changes after Toca 511 & Toca FC treatment in patients with advanced solid tumors, including colorectal cancer (CRC). Patients received intravenous (IV) Toca 511 for 3 days, and underwent biopsy of metastatic tumor before and ~ 4 weeks after starting oral Toca FC. Toca FC was repeated every 4-6 weeks. Peripheral blood mononuclear cells and tumor biopsies were evaluated for treatment related immune responses. Results: 17 CRC patients with a median 5 lines of prior chemotherapy were enrolled. At last data cut-off, 9 patients were alive and the median overall survival was 9.4 months. A patient receiving concomitant panitumumab had a partial response. IV Toca 511 led to viral expression in tumor, which decreased post-Toca FC while maintaining a reservoir of virus in the remaining tumor. T cells shifted from naïve to effector phenotypes, CD4 memory T cells expanded, and/or B cells increased after Toca FC treatment in 36% of patients. Marked changes in tumor infiltrating cells (CD11b myeloid cells, Tregs, exhausted T cells and CD8 T cells) occurred after Toca FC treatment. Treatment has been generally well tolerated. We also plan to report insights gained from RNA analysis of TME and update on clinical finding. Conclusions: Clinical data suggest a signal of activity in these heavily pretreated CRC patients warranting further exploration. IV Toca 511 administration showed viral infection of CRC metastatic tumor. Toca 511 & Toca FC may be associated with T cell mediated immune activity in peripheral blood and metastatic tumor, consistent with pre-clinical data in multiple tumor types. Clinical trial information: NCT02576665.

Toca 511 and Toca FC in patients with gastrointestinal tumors in the Toca 6 study

TPS880

Background: Toca 511 (vocimagene amiretrorepvec) is an investigational, conditionally lytic, retroviral replicating vector (RRV). RRVs selectively infect cancer cells due to defects in innate and adaptive immune responses found in cancers that support virus replication, and the requirement for cell division for virus integration into the genome. Toca 511 spreads through tumors, stably delivering an optimized cytosine deaminase (CD) gene that converts the prodrug, Toca FC (investigational, extended-release 5-FC) into 5-FU. 5-FU kills infected dividing cancer cells and diffuses and kills surrounding cancer cells, myeloid derived suppressor cells, and tumor associated macrophages, thus reestablishing tumor immunity (Cloughesy et al. Neuro Oncol 2016). In a Phase 1 study, resected high grade glioma tumors expressed CD protein following intravenous (IV) Toca 511.1 In animal models of metastatic colorectal cancer, IV Toca 511 infected metastatic sites, and subsequent 5-FC treatment resulted in decreased tumor size and improved survival (Yagiz et al. Mol Therapy 2015). Methods: Toca 6 is a Phase 1b, multicenter, open-label study (NCT02576665) that aims to investigate changes in immune activity after treatment with Toca 511 & Toca FC in patients with solid tumors, including gastrointestinal tumors. A total of 30 patients who have advanced malignancies, including colorectal and pancreatic cancer, with molecular characteristics that may increase sensitivity to 5-FU or viral infection, or IDH1 mutated solid tumors (e.g., intrahepatic cholangiocarcinoma) will be enrolled. In these patients, Toca 511 is injected IV daily for 3 days, then intratumorally after biopsy. Oral Toca FC is started ~4 weeks later and repeated every 4-6 weeks. Changes from baseline in intratumoral immune activity (infiltrating T-cell subpopulations, B cells, monocytes) at 4 weeks after start of Toca FC are assessed. Contemporaneous peripheral blood is analyzed for effector, memory, Treg, and myeloid lineage cells. Viral RNA, DNA, and CD protein expression in tumor after IV Toca 511 are measured. Safety and efficacy will be determined. Concomitant checkpoint inhibitor therapy may be given following immune activity assessments. The study has enrolled 3 patients. Clinical trial information: NCT02576665.

Safety and efficacy of TG101348, a selective JAK2 inhibitor, in myelofibrosis

PURPOSE

Myelofibrosis is a myeloid malignancy associated with anemia, splenomegaly, and constitutional symptoms. Patients frequently harbor JAK-STAT activating mutations that are sensitive to TG101348, a selective small-molecule Janus kinase 2 (JAK2) inhibitor.

PATIENTS AND METHODS

In a multicenter phase I trial, oral TG101348 was administered once a day to patients with high- or intermediate-risk primary or post-polycythemia vera/essential thrombocythemia myelofibrosis.

RESULTS

Fifty-nine patients were treated, including 28 in the dose-escalation phase. The maximum-tolerated dose was 680 mg/d, and dose-limiting toxicity was a reversible and asymptomatic increase in the serum amylase level. Forty-three patients (73%) continued treatment beyond six cycles; the median cumulative exposure to TG101348 was 380 days. Adverse events included nausea, vomiting, diarrhea, anemia, and thrombocytopenia; corresponding grades 3 to 4 incidence rates were 3%, 3%, 10%, 35%, and 24%. TG101348 treatment had modest effect on serum cytokine levels, but greater than half of the patients with early satiety, night sweats, fatigue, pruritus, and cough achieved rapid and durable improvement in these symptoms. By six and 12 cycles of treatment, 39% and 47% of patients, respectively, had achieved a spleen response per International Working Group criteria. The majority of patients with leukocytosis or thrombocytosis at baseline (n = 28 and n = 10, respectively) achieved normalization of blood counts after six (57% and 90%, respectively) and 12 (56% and 88%, respectively) cycles. A significant decrease in JAK2 V617F allele burden was observed at 6 months in mutation-positive patients (n = 51; P = .04), particularly in the subgroup with allele burden greater than 20% (n = 23; P < .01); the decrease was durable at 12 months.

CONCLUSION

TG101348 is well tolerated and produces significant reduction in disease burden and durable clinical benefit in patients with myelofibrosis.

In vivo lung deposition of hollow porous particles from a pressurized metered dose inhaler

PURPOSE

PulmoSphere particles are specifically engineered for delivery by the pulmonary route with a hollow and porous morphology, physical diameters < 5 microm, and low tap densities (circa 0.1 g x cm(-3)). Deposition of PulmoSphere particles in the human respiratory tract delivered by pressurized metered dose inhaler (pMDI) was compared with deposition of a conventional micronized drug pMDI formulation.

METHODS

Nine healthy nonsmoking subjects (5 male, 4 female) completed a two-way crossover gamma scintigraphic study, assessing the lung and oropharyngeal depositions of albuterol sulfate, formulated as 99mTc-radiolabeled PulmoSphere particles or micronized particles (Ventolin Evohaler, GlaxoSmithKline, Ltd.) suspended in HFA-134a propellant.

RESULTS

Mean (standard deviation) lung deposition, (% ex-valve dose) was doubled for the PulmoSphere formulation compared with Evohaler pMDI (28.5 (11.3) % vs. 14.5 (8.1) %, P < 0.01), whereas oropharyngeal deposition was reduced (42.6 (9.0) % vs. 72.0 (8.0) %, P < 0.01). Both PulmoSphere and Evohaler pMDIs gave uniform deposition patterns within the lungs.

CONCLUSIONS

These data provided "proof of concept" in vivo for the PulmoSphere technology as a method of improving targeting of drugs to the lower respiratory tract from pMDIs, and suggested that the PulmoSphere technology may also be suitable for the delivery of systemically acting molecules absorbed via the lung.

The safety and applications of acellular human dermal allograft in ophthalmic plastic and reconstructive surgery: a preliminary report

PURPOSE

To describe the uses and determine the safety of a commercially available acellular dermal allograft in ophthalmic plastic and reconstructive surgery. The existing literature regarding current applications and results using acellular dermal allograft is reviewed.

METHODS

The study design was a retrospective, noncomparative case series. Participants consisted of 63 consecutive patients undergoing ophthalmic plastic and reconstructive surgery using an acellular dermal matrix graft. The main intervention was placement of a dermal allograft. Outcome measures included the degree of clinical improvement and complications for each patient.

RESULTS

We used AlloDerm (LifeCell Corporation, The Woodlands, TX, U.S.A.) as a posterior lamellar conjunctival spacer graft, a soft tissue interpositional graft, and an orbital implant wrapping material. Clinical improvement was noted in all cases. There were no complications attributable to the acellular dermal matrix material.

CONCLUSIONS

We describe several novel ophthalmic plastic and reconstructive surgical applications using acellular dermal allograft tissue. This material may be used safely as a posterior lamellar conjunctival spacer graft, a soft tissue interpositional graft, and a wrapping material. Clinically, the allograft appears to be biocompatible, nontoxic, and nonallergenic in the orbit, eyelid, and midfacial tissues. Long-term data and studies comparing the efficacy of acellular dermal allograft with conventional materials are necessary.

Preclinical and clinical studies on lymph node imaging using perflubron emulsion

A perflubron emulsion is being developed as a contrast agent to enhance lymph nodes on computed tomography (CT) images. The emulsion is administered by percutaneous injection into the drainage field of the lymph nodes to be imaged. A series of preclinical studies was conducted to investigate the efficacy of the perflubron emulsion for enhancement of lymph nodes on CT images. The effects of dose (0.10 to 0.50 mL), application of massage, and route of administration were investigated in healthy New Zealand white rabbits. Results of these studies demonstrated that doses as low as 0.15 mL were efficacious for consistent enhancement of axillary lymph nodes on CT images after subcutaneous injections in the forepaw. Application of massage to the injection site decreased the time for maximum nodal enhancement from approximately 7 days to 2 days postinjection. A pilot study conducted in 18 healthy, male volunteers indicated dose-related enhancement of axillary lymph nodes on CT images following subcutaneous injections of the emulsion in the hand. Other than mild, transient injection-site discomfort, no clinically significant side effects were observed. These data demonstrate that the perflubron emulsion is safe and can enhance axillary lymph nodes on CT images following injections in the hand.

Job satisfaction. Assumptions and complexities

It has long been assumed that job satisfaction relates to employee turnover and quality of care. In this article the difficulties of measuring job satisfaction are discussed in light of results from a 6-month assessment by nurse employees in a university-affiliated acute care hospital. The authors found that job satisfaction scores were significantly predicted by respondents' job expectations and the importance they placed on various components of the work situation. The authors conclude that job satisfaction measurement is most valid and reliable when these two predictors are taken into account.

Antibodies to viral and non-viral antigens in subacute sclerosing panencephalitis and multiple sclerosis demonstrated by thin-layer polyacrylamide gel isoelectric focusing, antigen immunofixation and autoradiography

Antibody activity in IgG zones separated by thin-layer polyacrylamide gel isoelectric focusing (PAG IEF) was determined in 3 patients with subacute sclerosing panencephalitis (SSPE), 4 patients with multiple sclerosis (MS) and 4 subjects with psychosomatic disorders, using antigen immunofixation and autoradiography. Viral (measles herpes simplex type 1, mumps) and non-viral (purified bovine myelin, bovine myelin basic protein, bovine oligodendrocytes, MS and normal human brain extract) were used as antigens. All oligoclonal and some of the polyclonal CSF IgG zones in the patients with SSPE contained measles virus antibodies, as did some of the oligoclonal and polyclonal CSF IgG zones in 3 of the patients with MS. No antibodies were detectable in CSF or serum IgG zones against any of the non-viral antigens tested.

Observations on extradural morphine analgesia in various pain conditions

We report the extradural administration of low-dose morphine in 10 ml of 10% dextrose (2-3 mg) to 98 adult patients with various types of acute and chronic pain. Extradural morphine injections were given either via a Tuohy needle (single or repeat injection) or via an extradural catheter. Pain relief was evaluated by subjective scoring and by the subsequent need for systemic analgesics. In 56% of patients, pain relief was considered good or excellent, in 24% it was fair, and in 20%, poor. The best results were after surgery and trauma and in patients with advanced peripheral vascular disease. The analgesia of each dose of extradural morphine lasted for 8 h (mean range 4-36 h). There was no motor, sensory or sympathetic blockade and no respiratory or haemodynamic complications. Dizziness and vomiting occurred in two patients, and urinary retention for about 12 h in three.

Binding of the endogenous nonpeptide morphine-like compound to opiate receptors

The endogenous central nervous tissue substance called MLC (morphine-like compound) is shown to bind to the opiate receptors of the mouse neuroblastoma X glioma hybrid cell line NG108-15. The interaction of MLC with these opiate receptors is noncooperative, as is the interaction of morphine, naloxone, and Leu-enkephalin with these receptors. A specific antibody to morphine will bind MLC but will not bind beta-endorphin, Leu-enkephalin, or Met-enkephalin. It would appear, therefore, that MLC can be considered to be a different type of endogenous ligand for the opiate receptor.

Renin-like activity of the rat submaxillary gland: characterization and the effect of several drugs and stimuli

1. Renin-like activity was found in rat submaxillary glands.2. This activity was destroyed by boiling, was non-dialyzable and showed an optimum at approximately 50 degrees C.3. Renin-like activity in the submaxillary gland was not diminished 24 h after nephrectomy but was considerably reduced after ligature of the submaxillary duct.4. Renin-like activity in the submaxillary gland was reduced following food-deprivation, water-deprivation or hypovolemia.5. Renin-like activity in the rat submaxillary gland was increased after isoproterenol administration but not following pilocarpine.6. Renin-like activity in the rat submaxillary gland was increased considerably by administration of NaCl or KCl, as well as following adrenalectomy.7. Chlorothiazide and ouabain increased submaxillary renin-like activity but diazoxide did not affect this activity.