Innovations in medical marijuana research at the Center for Pharmacy Innovation & Outcomes

Authors: Melissa Kern and Brian Piper

The Center for Pharmacy Innovation & Outcomes (CPIO) continues to advance research in medical marijuana, also referred to as cannabis, through studies conducted at the national, state and local levels. These efforts are supported by grants from the Geisinger Academic Clinical Research Center and contribute to a growing body of evidence aimed at informing clinical practice and policy.

Recent investigations have explored the potential interaction between cannabis and immunotherapy, based on the presence of cannabinoid type 2 receptors on immune cells. While initial observational studies suggested a possible link, further analysis identified methodological limitations, including the failure to account for tobacco use — a known comorbidity in cancer treatment — and statistical inconsistencies. Subsequent work has demonstrated that artificial intelligence can be applied to detect and prevent common statistical errors in published research, including issues related to bivariate analysis, rounding and percentage reporting.

Policy-focused studies have examined the perspectives of pharmacists and other stakeholders regarding the inclusion of medical cannabis data in prescription drug monitoring programs (PDMPs). Unlike states such as New York and Ohio, Pennsylvania does not include cannabis information in its PDMP. This distinction has implications for clinical decision-making and regulatory oversight.

Additional research has assessed the alignment between Pennsylvania’s list of qualifying conditions for medical cannabis and the evidence ratings established by the National Academy of Sciences. Pennsylvania ranks 17th nationally, with 8.3% of its qualifying conditions supported by substantial or conclusive evidence, such as chronic pain, multiple sclerosis and chemotherapy-induced nausea and vomiting.

The CPIO has also identified persistent misconceptions surrounding medical marijuana, including the belief that it is prescribed or dispensed through traditional pharmacies.

These inaccuracies have occasionally been communicated by healthcare providers, underscoring the need for improved education and clarity in patient-provider interactions.

Utilization trends indicate a significant increase in medical cannabis certifications among Pennsylvania adults, rising from 0.6% in 2018 to 3.8% in 2021. Certain counties, such as Montour, report disproportionately high certification rates relative to population size, while Lackawanna County ranks second statewide for certifications related to chronic pain.

Collectively, these research efforts provide a foundation for future policy development as Pennsylvania considers adult-use legalization and the federal government evaluates reclassification of cannabis from Schedule I to Schedule III. The CPIO remains committed to generating evidence that informs safe, effective, transparent use of medical marijuana in health systems.

Relevant publications

1. Piper BJ, Tian M, Saini P, Higazy A, Graham J, Carbe CJ, Bordonaro M. Immunotherapy and Cannabis: A Harmful Drug Interaction or Reefer Madness? Cancers (Basel). 2024 Mar 22;16(7):1245. doi: 10.3390/cancers16071245. PMID: 38610922; PMCID: PMC11011043.
2. Piper BJ, Dobbins DX; et al. Commentary on “Bar-Sela et al. Cannabis consumption used by cancer patients during immunotherapy correlates with poor clinical outcome. Cancers 2020, 12, 2447”. Cancers. 2025. In press.
3. Gregor CM, Tian MY, Tusing LD, Wright EA, Piper BJ, Romagnoli KM. State policies and clinicians’ and administrators’ perspectives on the inclusion of Medical Cannabis information in the Prescription Drug Monitoring Program. MedRxiv. 2025 Jul 25. doi: https://doi.org/10.1101/2025.07.24.25332003
4. Stains EL, Kennalley AL, Tian M, Boehnke KF, Kraus CK, Piper BJ. Medical Cannabis in the United States: Comparing 2017 and 2024 State Qualifying Conditions to the 2017 National Academies of Sciences Report. Mayo Clin Proc Innov Qual Outcomes. 2025 Feb 20;9(2):100590. doi: 10.1016/j.mayocpiqo.2025.100590. PMID: 40066150; PMCID: PMC11891685.
5. Kennalley AL, Tian M, Higazy A, Blank S, Stains EL, Piper BJ. Marijuana misconceptions and myths. Musculoskeletal Matters. Fall 2024, 16-17. https://www.mskmatters.org/_files/ugd/065161_c930b25959c148b0916302c63da8c278.pdf.
6. Shetty VA, Gregor CM, Tusing LD, Pradhan AM, Romagnoli KM, Piper BJ, Wright EA. Discussions of Cannabis Over Patient Portal Secure Messaging: Content Analysis. J Med Internet Res. 2024 Dec 12;26:e63311. doi: 10.2196/63311. PMID: 39666375; PMCID: PMC11671783.
7. Hirsch AG, Wright EA, Nordberg CM, DeWalle J, Stains EL, Kennalley AL, Zhang J, Tusing LD, Piper BJ. Dispensaries and Medical Marijuana Certifications and Indications: Unveiling the Geographic Connections in Pennsylvania, USA. Med Cannabis Cannabinoids. 2024 Feb 20;7(1):34-43. doi: 10.1159/000537841. PMID: 38487377; PMCID: PMC10939510.
8. Mehta SK, Tusing LD, Higazy A, Piper BJ. Medical cannabis certifications for severe chronic and intractable pain: Discerning geographic patterns across Pennsylvania, USA. MedRxiv, 2025 Jun 26. doi: https://doi.org/10.1101/2025.06.25.25329221