FDA Grants RPDD and ODD to FL118 for Osteosarcoma

The FDA granted both rare pediatric disease designation (RPDD) and orphan drug designation (ODD) to FL118 for the treatment of osteosarcoma, according to a news release from Roswell Park Comprehensive Cancer Center and its spinoff company Canget BioTekpharma LLC.¹ The dual regulatory designations are intended to support development of therapies for rare diseases and may provide incentives that could accelerate clinical development of the investigational agent.

“Receiving both [RPDD] and [ODD] for FL118 in osteosarcoma is an important milestone for this Roswell Park-discovered compound,” Fengzhi Li, PhD, associate professor of oncology in the department of Pharmacology and Therapeutics at Roswell Park and founder of Canget BioTekpharma, stated in the news release. “These designations recognize the unmet medical needs in osteosarcoma and provide meaningful regulatory incentives that may help advance FL118 toward further development for pediatric and rare cancers.”

Disease and Drug Background

Osteosarcoma remains a rare and aggressive bone malignancy that most commonly affects children, adolescents, and young adults with limited treatment options for recurrent disease. The unmet clinical need in these populations continues to drive interest in novel therapeutic strategies. According to the release, FL118 has demonstrated broad anticancer activity in preclinical studies and may affect pathways associated with cancer-cell survival and drug resistance.

As a small-molecule dual molecular glue degrader, FL118 can selectively target DDX5 and UbE2T, which are involved in cancer DNA repair pathways in multiple difficult-to-treat malignancies.² DDX5 is a therapeutic target in osteosarcoma associated with tumor progression, and UbE2T is highly expressed in osteosarcoma tissues and correlates to resistance to radiotherapy. It was previously granted ODD status for pancreatic cancer in 2024. The Roswell Park group reported that emerging evidence suggests FL118 may serve as a platform for development of related compounds targeting additional malignancies including malignant pleural mesothelioma.¹

Xiang Ling, MD, PhD, a senior researcher for Roswell Park’s FL118 team, stated that the investigational compound has shown “unexpected anticancer activity with a favorable preclinical toxicity profile” in laboratory studies. Ling added that ongoing mechanistic investigations continue to provide insight into the compound’s activity. The preclinical cell models and xenografts showed both minimal toxicity as well as the ability to bypass dense stroma that often limit drug penetration in osteosarcoma.²

The FDA’s ODD program is designed to encourage the development of therapies for rare diseases, while the RPDD program supports therapies targeting serious or life-threatening diseases that primarily affect pediatric populations. If FL118 ultimately receives approval for a qualifying pediatric indication and meets statutory requirements, Canget BioTekpharma could become eligible for a priority review voucher from the FDA. The FDA designations may provide several development incentives, including regulatory support and increased visibility for collaboration opportunities focused on rare pediatric cancers.

FL118 originated from research conducted at Roswell Park, a National Cancer Institute-designated comprehensive cancer center in Buffalo, New York. The institution stated that the compound’s development reflects broader efforts to translate laboratory discoveries into potential therapeutic options for patients with difficult-to-treat cancers.¹

REFERENCES

1. FL118 granted FDA rare pediatric disease designation and orphan drug designation for osteosarcoma. News release. Roswell Park Comprehensive Cancer Center. May 19, 2026. Accessed May 21, 2026. https://tinyurl.com/shjbka6y

2. Li F, Ling X, Chakraborty S, et al. DDX5 (p68) and UbE2T as emerging superior cancer therapeutic targets: dual molecular glue target degradation by FL118 for conquering difficult-to-treat cancers. J Exp Clin Cancer Res. Published online May 18, 2026. doi:10.1186/s13046-026-03733-3