Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction (MARSH): A pilot, first-in-human study of interferon gamma-stimulated marrow mesenchymal stromal cells for treatment of radiation-induced xerostomia.

BACKGROUND AIMS: Xerostomia, or the feeling of dry mouth, is a significant side effect of radiation therapy for patients with head and neck cancer (HNC). Preliminary data suggest that mesenchymal stromal/stem cells (MSCs) can improve salivary function. We performed a first-in-human pilot study of interferon gamma (IFNγ)-stimulated autologous bone marrow-derived MSCs, or MSC(M), for the treatment of radiation-induced xerostomia (RIX). Here we present the primary safety and secondary efficacy endpoints. METHODS: A single-center pilot clinical trial was conducted investigating the safety and tolerability of autologous IFNγ-stimulated MSC(M). The study was conducted under an approved Food and Drug Administration Investigational New Drug application using an institutional review board-approved protocol (NCT04489732). Patients underwent iliac crest bone marrow aspirate and MSC(M) were isolated, cultured, stimulated with IFNγ and cryopreserved for later use. Banked cells were thawed and allowed to recover in culture before patients received a single injection of 10 × 106 MSC(M) into the right submandibular gland under ultrasound guidance. The primary objective was determination of safety and tolerability by evaluating dose-limiting toxicity (DLT). A DLT was defined as submandibular pain >5 on a standard 10-point pain scale or any serious adverse event (SAE) within 1 month after injection. Secondary objectives included analysis of efficacy as measured by salivary quantification and using three validated quality of life instruments. Quantitative results are reported as mean and standard deviation. RESULTS: Six patients with radiation-induced xerostomia who had completed radiation at least 2 years previously (average 7.8 years previously) were enrolled in the pilot study. The median age was 71 (61-74) years. Five (83%) patients were male. Five patients (83%) were treated with chemoradiation and one patient (17%) with radiation alone. Grade 1 pain was seen in 50% of patients after submandibular gland injection; all pain resolved within 4 days. No patients reported pain 1 month after injection, with no SAE or other DLTs reported 1 month after injection. The analysis of secondary endpoints demonstrated a trend of increased salivary production. Three patients (50%) had an increase in unstimulated saliva at 1 and 3 months after MSC(M) injection. Quality of life surveys also showed a trend toward improvement. CONCLUSIONS: Injection of autologous IFNγ-stimulated MSC(M) into a singular submandibular gland of patients with RIX is safe and well tolerated in this pilot study. A trend toward an improvement in secondary endpoints of salivary quantity and quality of life was observed. This first-in-human study provides support for further investigation into IFNγ-stimulated MSC(M) injected in both submandibular glands as an innovative approach to treat RIX and improve quality of life for patients with HNC.

Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction (MARSH): Study protocol for a phase 1 dose-escalation trial of patients with xerostomia after radiation therapy for head and neck cancer: MARSH: Marrow-Derived Autologous Stromal Cells for the Restoration of Salivary Hypofunction.

BACKGROUND: Xerostomia, or dry mouth, is a common side effect of head and neck radiation. Current treatment options for radiation-induced xerostomia are generally supportive in nature. Adult stem cells are the ultimate source for replenishment of salivary gland tissue. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are a viable cell-based therapy for xerostomia. We have undertaken studies enabling U.S. Food and Drug Administration Investigational New Drug status, demonstrating the normal phenotype, intact functionality, and pro-growth secretome of interferon-γ (IFNγ)-stimulated BM-MSCs taken from patients with head and neck cancer who have undergone radiation ± chemotherapy. Here we present the protocol of MARSH, a first-in-human clinical trial of bone marrow-derived, IFNγ-activated BM-MSCs for the treatment of radiation-induced xerostomia. METHODS: This single-center phase 1 dose-escalation with expansion cohort, non-placebo-controlled study will assess the safety and tolerability of BM-MSCs for the treatment of radiation-induced xerostomia in patients who had head and neck cancer. The phase 1 dose-escalation study will be a 3 + 3 design with staggered enrollment. A total of 21 to 30 subjects (9 to 18 in phase 1 study, 12 in expansion cohort) will be enrolled. The primary endpoint is determining the recommended phase 2 dose (RP2D) of IFNγ-stimulated BM-MSCs to enable further studies on the efficacy of BM-MSCs. Patients' bone marrow will be aspirated, and BM-MSCs will be expanded, stimulated with IFNγ, and injected into the submandibular gland. The RP2D will be determined by dose-limiting toxicities occurring within 1 month of BM-MSC injection. Secondary outcomes of saliva amounts and composition, ultrasound of salivary glands, and quality of life surveys will be taken at 3-, 6-, 12-, and 24-month visits. DISCUSSION: Autotransplantation of IFNγ-stimulated BM-MSCs in salivary glands after radiation therapy or chemoradiation therapy may provide an innovative remedy to treat xerostomia and restore quality of life. This is the first therapy for radiation-induced xerostomia that may be curative. TRIAL REGISTRATION: World Health Organization International Clinical Trials Registry Platform: NCT04489732.

A Pilot Study of Perceived Mouth Dryness, Perceived Swallowing Effort, and Saliva Substitute Effects in Healthy Adults Across the Age Range.

Xerostomia, or perceived mouth dryness, increases with advancing age, but its influence on swallowing effort is unknown. This study: (1) quantified relationships among age, perceived sense of swallowing effort, and ratings of perceived mouth dryness, and (2) examined changes in swallowing effort following application of a gel-based saliva substitute in healthy participants. This was a cross-sectional observational study and data were collected from attendees of a community healthy aging fair. Forty-two healthy participants (mean age = 65 years; 20 female) were enrolled. Each participant rated perceived effort with swallowing and perceived mouth dryness on a 10-cm horizontal, undifferentiated line. After participants applied a gel-based saliva substitute (Biotene® Oral Balance) to their tongue and oral mucosa, they rated perceived effort with swallowing again. Age was associated with greater perceived mouth dryness (r = 0.37, p < 0.03) but not with perceived swallowing effort (r = 0.16, p = 0.32). Perceived mouth dryness was associated with greater perceived swallowing effort (r = 0.62, p < 0.001). Perceived swallowing effort declined following application of the salivary substitute (mean difference = 9.39 mm, p < 0.002). Age was found to be a significant predictor of perceived mouth dryness (p < .02); and perceived mouth dryness was found to significantly predict perceived swallow effort (p < .001). Perceived mouth dryness increased with advancing age, but perceived swallowing effort did not. Regardless of age, participants with higher levels of perceived mouth dryness also reported more perceived effort with swallowing suggesting a role for adequate oral lubrication in this perception. Even in healthy participants, use of a gel-based saliva substitute lowered perceived swallowing effort.

Effects of Change in Tongue Pressure and Salivary Flow Rate on Swallow Efficiency Following Chemoradiation Treatment for Head and Neck Cancer.

Patients treated with chemoradiation for head and neck cancer frequently develop dysphagia. Tissue damage to the oral tongue causing weakness along with decreases in saliva production may contribute to dysphagia. Yet, effects of these variables on swallowing-related measures are unclear. The purpose of this study was (1) to determine effects of chemoradiation on tongue pressures, as a surrogate for strength, and salivary flow rates and (2) to elucidate relationships among tongue pressures, saliva production, and swallowing efficiency by bolus type. Twenty-one patients with head and neck cancer treated with chemoradiation were assessed before and after treatment and matched with 21 healthy control participants who did not receive chemoradiation. Each participant was given a questionnaire to rate dysphagia symptoms. Videofluoroscopic Evaluation of Swallowing (VFES) was used to determine swallowing efficiency; the Saxon test measured salivary flow rate; and the Iowa Oral Performance Instrument (IOPI) was used for oral tongue maximum and endurance measures. Results revealed significantly lower tongue endurance measures for patients post-treatment as compared to controls (p = .012). Salivary flow rates also were lower compared to pre-treatment (p = .000) and controls (p = .000). Simple linear regression analyses showed that change in salivary flow rate was predictive of change in swallow efficiency measures from pre- to post-treatment for 1 mL thin liquid (p = .017), 3 mL nectar-thick liquid (p = .026), and 3 mL standard barium pudding (p = .011) boluses. Based on these findings, it appears that chemoradiation treatment affects tongue endurance and salivary flow rate, and these changes may impact swallow efficiency. These factors should be considered when planning treatment for dysphagia.

Changes in swallowing physiology and patient perception of swallowing function following chemoradiation for head and neck cancer.

Patients treated with chemoradiation for head and neck cancer often report difficulty with swallowing and are frequently diagnosed with dysphagia. The extent to which patient awareness of dysphagia corresponds to observed physiologic changes in swallowing is unclear. The purpose of this study was to determine how both patient awareness of swallowing function and swallowing physiology individually change following chemoradiation and then to clarify the relationship between them. Twenty-one patients with head and neck cancer treated with chemoradiation were assessed before and after treatment and matched with twenty-one control subjects. The modified barium swallow test was utilized to examine swallowing physiology. Each subject was also given a series of items regarding awareness of specific dysphagia symptoms. Results showed decreased swallow efficiencies, higher percentages of residue, and more occurrences of penetration and aspiration following chemoradiation. Patients also had significantly higher ratings for 4 of the 12 items ("dry mouth," "food sticking in my mouth," "need water to help food go down," and "change in sense of taste"). Only one strong and significant correlation was found between ratings for "I have difficulty swallowing" and swallow efficiency values. Based on these findings, it appears that patients sense a general difficulty with swallowing but have less awareness of specific symptoms of dysphagia.

Quantification of very late xerostomia in head and neck cancer patients after irradiation.

Objective: Radiation therapy (RT) for head and neck cancer (HNC) can result in severe xerostomia, or the subjective feeling of dry mouth. Characterizing xerostomia is critical to designing future clinical trials investigating how to improve HNC patients' quality of life (QoL). Few studies have investigated the very late (>5 years post-RT) effects of RT for HNC. We undertook preliminary studies quantifying very late xerostomia. Methods: Six adults who underwent RT for HNC at least 5 years prior and reported xerostomia were enrolled. Five healthy adults without a self-reported history of HNC or xerostomia were enrolled as controls. All participants completed three validated surveys to measure xerostomia-related QoL. Salivary production rates were measured and compositional analysis of the saliva and oral microbiome was completed. Results: The QoL survey scores for the HNC participants were significantly worse as compared to the control participants. The HNC participants produced less unstimulated saliva (p = .02) but not less stimulated saliva. The median salivary mucin significantly higher in HNC participants than in control participants (p = .02). There was no significant difference between the pH, amylase, or total protein. Microbiome analysis revealed alpha diversity to be significantly lower in the HNC participants. Conclusion: In the survivors of HNC who suffer from late toxicities, multiple means of measuring toxicity may be useful. We found that in patients with radiation-induced xerostomia over 5 years after therapy, not only were the QoL surveys significantly worse, as expected, but other measurements such as mucin and oral microbiome diversity were also significantly different. Level of evidence: 3.

Effects of reduced saliva production on swallowing in patients with Sjogren's syndrome.

This study aimed to further characterize the nature of swallowing dysfunction in patients with Sjogren's syndrome (SS). Subjects filled out a perception of swallow function form. Measures of stimulated salivary flow rate were also taken, and videofluoroscopic evaluation of swallowing was completed. The amount of saliva produced by patients with SS was significantly less than that produced by normal age-matched controls, and these patients perceived their swallowing to be impaired. Few statistically significant differences were found between the SS group and normal age-matched controls on temporal measures of swallowing, and 96% of swallows in the SS group were judged to be functional. There was no correlation between perception of swallowing and amount of saliva produced. No strong correlations were found between temporal measures of swallowing and salivary flow rate. Results indicated that patients with SS tend to perceive their swallowing to be worse than physiologic swallowing measures indicate. The decreased saliva production in these patients does not appear to be the cause of their perceived swallowing difficulty but may affect their sensory judgment of swallow function. Future studies will focus on how quality of saliva affects swallowing in these patients.