Dialing for doctors: Secret shopper study of Arizona methadone and buprenorphine providers, 2022

INTRODUCTION

Methadone and buprenorphine are effective and safe treatments for opioid use disorder (OUD) and also reduce overdose and all-cause mortality. Identifying and reaching providers of medication for opioid use disorder (MOUD) has proven difficult for prospective patients and researchers.

OBJECTIVES

To assess the accuracy of government-maintained lists of Arizona (AZ) providers prescribing MOUD, and the extent to which these providers are accessible for treatment.

METHODS

A two-phase study used a listing of 2376 AZ MOUD providers obtained from the U.S. Drug Enforcement Administration and the Substance Abuse and Mental Health Services Administration. Phase 1 assessed the accuracy of the listing using internet confirmatory research from May-October 2022. Phase 2 used the resulting list of 838 providers to assess provider availability, type of MOUD treatment provided, and accepted payment through secret shopper calls between November 16 and 30, 2022.

RESULTS

Just over half (52.2 %, n = 1240) of providers were removed from the original listing during Phase 1. One quarter (25.9 %) were no longer in practice. Among the 833 eligible for the secret shopper Phase 2 study, 36.6 % (n = 307) were reached and identified as providing MOUD. A vast majority (88.1 %) of MOUD providers indicating treatment type were accepting new patients, however methadone was identified far more frequently than was likely permitted or provided for OUD. Providers were 5.5 times more likely to accept new patients if they accepted cash payment for services, and 4.9 times more likely if they accepted Medicaid. Rural areas remained underserved.

CONCLUSIONS

The active population of MOUD providers is far smaller than surmised. DEA and SAMHSA provider listings are not sufficiently accurate for survey research sampling. Other means of representative sampling will need to be devised, and trusted lists of providers for prospective patients should be promoted, publicly available, and regularly maintained for accuracy. Providers that offer treatment should assure that public-facing staff have basic information about the practice, the treatment offered, and conditions for taking new patients. Concerted efforts must assure rural access at the most local levels to reduce patient travel burden.

Abstract 4069: Development of PSB205, a bifunctional MabPair product that targets PD-1 and CTLA-4

Here we describe a novel platform that enables the production of two full length IgG molecules from a single production cell line. This technology was achieved using a molecular engineering approach to precisely control the cognate pairing of antibody heavy chains and light chains during the assembly of two antibodies in the same cell line. This technology platform, which has been designated as MabPair, can be applied for the development of therapeutic antibody products that contain a mixture of two different antibodies. The antibody cocktail is produced by the same cell line in a predefined ratio and can be manufactured using a conventional antibody production process. When addressing multiple targets, MabPair products can offer significant advantages and flexibility over a bispecific antibody. MabPair technology represents a novel approach for developing antibody combination products. This approach is exemplified by the development of PSB205, our lead MabPair product candidate. PSB205 targets two immune checkpoint pathways, PD-1 and CTLA-4. The development of PSB205, as a potential anti-cancer immunotherapeutic, is discussed.

Citation Format: William C. Fanslow, Zhi Liu, Zhonghua Hu, Hua Liu, Min Shen, Yufeng Peng, Cristina Domeier, David Treiber, Ron Schoner, Wei Yan. Development of PSB205, a bifunctional MabPair product that targets PD-1 and CTLA-4 [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 4069.

Use of a small molecule cell cycle inhibitor to control cell growth and improve specific productivity and product quality of recombinant proteins in CHO cell cultures

The continued need to improve therapeutic recombinant protein productivity has led to ongoing assessment of appropriate strategies in the biopharmaceutical industry to establish robust processes with optimized critical variables, that is, viable cell density (VCD) and specific productivity (product per cell, qP). Even though high VCD is a positive factor for titer, uncontrolled proliferation beyond a certain cell mass is also undesirable. To enable efficient process development to achieve consistent and predictable growth arrest while maintaining VCD, as well as improving qP, without negative impacts on product quality from clone to clone, we identified an approach that directly targets the cell cycle G1-checkpoint by selectively inhibiting the function of cyclin dependent kinases (CDK) 4/6 with a small molecule compound. Results from studies on multiple recombinant Chinese hamster ovary (CHO) cell lines demonstrate that the selective inhibitor can mediate a complete and sustained G0/G1 arrest without impacting G2/M phase. Cell proliferation is consistently and rapidly controlled in all recombinant cell lines at one concentration of this inhibitor throughout the production processes with specific productivities increased up to 110 pg/cell/day. Additionally, the product quality attributes of the mAb, with regard to high molecular weight (HMW) and glycan profile, are not negatively impacted. In fact, high mannose is decreased after treatment, which is in contrast to other established growth control methods such as reducing culture temperature. Microarray analysis showed major differences in expression of regulatory genes of the glycosylation and cell cycle signaling pathways between these different growth control methods. Overall, our observations showed that cell cycle arrest by directly targeting CDK4/6 using selective inhibitor compound can be utilized consistently and rapidly to optimize process parameters, such as cell growth, qP, and glycosylation profile in recombinant antibody production cultures.

Enhanced antigenicity of autologous leukemia cells enriched with cholesterylhemisuccinate

Cholesterylhemisuccinate (CHS) has been used by different authors to enhance the antigenicity of tumor cells in human and in animals. In the present study, leukemic cells isolated mainly from patients with chronic myeloid and chronic lymphocytic leukemia were incubated for 90 min at 37 degrees in PBS containing 3.5% polyvinylpyrrolidone, 0.5% glucose, 1% human serum albumin and 150 micrograms/ml CHS 5 x 10(6) pretreated, irradiated, autologous leukemic cells were tested for their ability to elicit a delayed type hypersensitivity skin reaction. The negative controls included CHS-treated and untreated non-leukemic autologous blood cells as well as substance controls. Recall antigens such as tetanus, diphtheria and tuberculine included in the Multitest Mérieux served as positive controls. Results from 28 patients and 44 skin tests are presented. 19 of 23 patients tested under the best of experimental conditions generated a positive skin reaction with the CHS-treated autologous leukemic cells. Less than 12% of the patients reacted with any of the above negative controls. Under the same conditions, more than 90% of the CLL patients were reactive. 5 CLL patients were selected for a treatment including 6 weekly injections of 5 x 10(6) to 5 x 10(8) autologous CLL cells. 3 patients experienced an up to 60% reduction of their initial leukocyte counts. In one patient, the leukocyte counts continued to decrease more than 6 months after the treatment was completed. One patient showed no response and in one patient with increasing leukocytes this increase could not be reversed. The results are discussed in terms of earlier observations that membrane sterol content influences the presentation of cell surface proteins.