FDA Issues Complete Response Letter for AbbVie’s 24-Hour Continuous Carbidopa/Levodopa Pump

Thomas Hudson, MD

After submitting the new drug application (NDA) in May 2022, AbbVie has received a complete response letter (CRL) for its investigational 24-hour continuous foscarbidopa/foslevodopa pump, or ABBV-951, for the treatment of motor fluctuations in adults with advanced Parkinson disease (PD). AbbVie plans to resubmit the NDA as soon as possible.¹

"There is an unmet need for people living with advanced Parkinson's disease as they face daily challenges in managing their condition," Thomas Hudson, MD, senior vice president, Research and Development, chief scientific officer, AbbVie, said in a statement. “We will continue to work closely with the FDA as part of our commitment to bringing this treatment option to people impacted by this disease as quickly as possible."

In the CRL, the agency requested additional information on the pump as part of its review, but did not request AbbVie to conduct additional efficacy and safety trials related to the drug. If approved, ABBV-951 will become the first subcutaneous delivery of carbidopa/levodopa, the standard of care for patients with PD, representing a potentially landscape-altering treatment option.

The NDA was based on the phase 3 M15-736 study (NCT04380142), a double-blind, double-dummy trial in which treatment with the therapeutic resulted in increased ON time by 2.72 hours over a 12-week period to 0.97 hours for oral levodopa/carbidopa (LD/CD). Comprising of 130 adults with advanced PD, the trial randomly assigned individuals 1:1 to either ABBV-951 solution as a continuous infusion under the skin plus oral placebo capsules for LD/CD or ABBV-951 as a subcutaneous infusion plus oral capsules containing LD/CD encapsulated tablets.²

If approved, this would mark AbbVie’s second major regulatory success for patients with PD in the last 7 years. In 2015, the FDA approved Duopa, the first and, to date, only treatment providing 16 continuous hours of LD/CD to help control motor fluctuations in advanced PD. The eternal suspension is administered using a small, portable pump that delivers LD/CD directly into the small intestine through a tube placed during an outpatient procedure.³

ABBV-951 also showed a good safety profile in the phase 3 study, with most of the reported adverse events (AEs) either mild or moderate in a nature. Serious AEs occurred in 8% ABBV-951 group compared with 6% in the LD/CD group. Notably, there as 1 death recorded in the study, believed to be from a treatment-emergent AE while in the LD/CD group. At week 12, ABBV-951-treated patients showed a decrease of 2.75 hours in OFF time, with changes observed as early as the first week. In comparison, those in the oral LD/CD group demonstrated decreases of 0.96 hours during the same stretch (P = .0054).

REFERENCES
1. AbbVie provides regulatory update on ABBV-951 (foscarbidopa/foslevodopa) new drug application. News release. AbbVie. March 22, 2023. Accessed March 22, 2023. https://news.abbvie.com/article_display.cfm?article_id=12567
2. Soileau MJ, Aldred J, Budur K, et al. Safety and efficacy of continous subcutaneous foslevodopa-foscarbidopa in patients with advanced Parkinson’s disease: a randomized, double-blind, active-controlled, phase 3 trial. Lancet Neurol. 2022;21(12):1099-1109. doi:10.1016/S1474-4422(22)00400-8.