Carbidopa/Levodopa

iStock, undefined undefined The FDA detected 14 cases of vitamin B6 deficiency–linked seizures and two deaths in patients with Parkinson’s disease taking carbidopa/levodopa drugs. Both AbbVie and Novartis market levodopa-based products. Products containing levodopa and carbidopa, a common drug combination for treating Parkinson’s disease, could trigger seizures, the FDA has found. The agency conducted a safety review of drugs carrying these compounds and found 14 cases of seizures linked to vitamin B6 deficiency, according to a safety alert on Friday. In all of these cases, levodopa doses exceeded 1,000 mg per day. Seizures were typically focal-onset, meaning they started in a limited region of the brain. They then spread to include both hemispheres, leading to convulsions and causing emergencies in some cases. Two patients died, both of whom had had low vitamin B6 levels and poorly controlled seizures, the FDA said. Nine patients were given vitamin B6 supplementation, which in all cases led to the resolution of their seizures. All 14 cases of carbidopa/levodopa-linked seizures were detected through post-marketing surveillance or found in the medical literature, “so there are likely additional cases about which we are unaware,” the FDA said. While the safety signals arose in those taking oral formulations and enteral suspensions of carbidopa/levodopa, the regulator did not dismiss the possibility that other products—such as injectables or those that use additional compounds to enhance the original drug combo—could carry the same risk. “Biological plausibility suggests there may be a similar risk across all drug products containing carbidopa/levodopa,” the FDA wrote. The agency has already notified all manufacturers of drugs carrying carbidopa/levodopa, asking them to update the labels of their respective products to carry warnings for vitamin B6 deficiency-associated seizures. In the meantime, healthcare professionals should assess their patients’ vitamin B6 levels at baseline and throughout treatment, and consider supplementation as needed, the FDA recommended. Levodopa is a synthetic drug that, once it reaches the brain, is converted into dopamine, a neurotransmitter that is deficient in patients with Parkinson’s disease. Levodopa’s therapeutic benefits for Parkinson’s were first established in the 1960s, and the first drug that combined it with the decarboxylase inhibitor carbidopa—which improved its efficacy and safety—entered the market in 1975 . The combo remains in use today. In October 2024, the FDA approved AbbVie’s Vyalev , a levodopa-based therapy for advanced Parkinson’s disease. The product contains foscarbidopa and foslevodopa, prodrugs that can be given continuously over 24 hours as a subcutaneous infusion. Novartis also owns a carbidopa/levodopa product in Stalevo , which additionally uses entacapone to sustain heightened levels of the drug in the bloodstream. The industry is now opening up new therapeutic avenues for Parkinson’s disease, however. Eli Lilly in January scooped up Ventyx Biosciences for $1.2 billion, gaining access to a pipeline of drugs that target the NLRP3 inflammatory cascade, an underlying pathway driving the condition. Also looking at an immune-centered approach to Parkinson’s is AC Immune, which in December 2025 demonstrated slower disease progression in patients treated with its anti-alpha-synuclein therapy. Parkinson’s disease 5 Investigational Therapies That Could Change the Parkinson’s Landscape From opening new therapeutic mechanisms to repairing neuronal damage, investigational molecules from Ventyx Therapeutics, AC Immune, Gain Therapeutics and more could shape the future of Parkinson’s disease treatment. January 26, 2026 · 9 min read · Tristan Manalac Read more

After Europe's CHMP signed off on Moderna's combination COVID-19 and flu vaccine, CEO Stéphane Bancel praised the "EMA’s rigorous scientific review." While the FDA has flip-flopped on whether to review Moderna’s combination influenza and COVID-19 vaccine, it’s full speed ahead for the mRNA shot in Europe.The Committee for Medicinal Products for Human Use (CHMP) has recommended granting marketing authorization to mCombriax for people aged 50 and older. The committee's thumbs up is the first for a combo vaccine that protects against the two respiratory infections. Earlier this month, the FDA sent a refusal-to-file (RTF) letter to Moderna, explaining that the comparator arm of the successful trial backing the submission did not “reflect the best-available standard of care.” Eight days later, after meeting with Moderna, the U.S. regulator accepted the company’s application and established an Aug. 5 action date for its decision on whether to approve the shot. The hesitance of the FDA and the quick sign off from the European Medicines Agency (EMA) highlights the differing regulatory environments vaccine makers are facing in their two largest markets. The regulators were largely aligned until the installation last year of vaccine skeptic Robert F. Kennedy Jr. as the chief of Health and Human Services (HHS).“We appreciate the EMA’s rigorous scientific review,” Moderna CEO Stéphane Bancel said in a release on Friday.It’s a much-needed win for Moderna, which has slumped since its overwhelming success with mRNA vaccine Spikevax, which generated $37 billion in revenue for the company in 2021 and 2022. “The CHMP’s positive opinion represents an important milestone for respiratory virus vaccination and for Moderna, with the introduction of the world’s first flu plus COVID combination vaccine,” Bancel added. “If approved, this would be Moderna’s fourth marketed product in Europe.”  In addition to the growing anti-vaccine sentiment in the U.S.—much of it fueled by misinformation—there is particular distrust from regulators in the U.S. about mRNA products, despite evidence of their safety.In making its decision, the CHMP cited World Health Organization data, which showed there have been more than 281 million cases of COVID-19 reported in Europe up until Feb. 1 of this year. Additionally, there are up to 50 million cases of seasonal flu each year in Europe. Sleeping sickness nod The CHMP has also recommended Acoziborole Winthrop as a treatment for gambiense sleeping sickness, a parasitic disease which is transmitted by the bite of an infected tsetse fly and has killed millions in central and west Africa over the past century. The medicine was co-developed by Sanofi and the Drugs for Neglected Diseases initiative (DNDi).The single-dose oral treatment would provide a significant advance over current therapies, which require either a 10-day course of oral medicine or a combination of injections and oral therapy for advanced cases. The recommendation applies to early and advanced-stage gambiense in those ages 12 and older.“In just 20 years, we have gone from complicated treatments including arsenic derivatives with serious side effects, to today, when a single-dose, one-day therapy could safely cure patients,” Luis Pizarro, M.D., the executive director of DNDi, said in a release. “This progress is [a] testament to the transformative power of collaborative science.” Two CHMP recommendations for hives condition Meanwhile, Novartis has secured a positive opinion from the CHMP on remibrutinib as an oral treatment for adults with chronic spontaneous urticaria (CSU) who have an inadequate response to antihistamines. In September of last year, the FDA approved the Bruton’s tyrosine kinase inhibitor (BTKi) treatment for the same indication, also known as chronic hives. The medicine’s commercial moniker in the U.S. is Rhapsido.“The introduction of remibrutinib represents a major advancement … with improvements in symptoms observed as early as Week 1,” Martin Metz, M.D., of the Institute of Allergology, Charité Universitätsmedizin in Berlin, said in a release.Sanofi also gained a CHMP positive opinion for its Regeneron-partnered blockbuster, Dupixent, as a treatment for children ages two through 11 years with CSU. This is the first biologic treatment for those under age 12 with the disorder. The FDA, which approved Dupixent for CSU in April of last year, has an April decision date on whether to expand its use to those ages of two through 11.Earlier this week, the FDA signed off on Dupixent in its ninth indication, allergic fungal rhinosinusitis (AFRS). Other CHMP recommendations Ipsen has scored a CHMP positive recommendation for its Day One Biopharmaceuticals-partnered Ojemda (tovorafenib) for patients six months of age and older with relapsed or refractory pediatric low-grade glioma (pLGG), a type of cancerous brain tumor.The FDA endorsed Ojemda, a once-weekly oral therapy, in 2024. It competes with Novartis’ Tafinlar-Mekinist combo, which has a narrower label. The treatments provide an option to surgery and chemotherapy.Also scoring a CHMP nod is Mitsubishi Tanabe’s Onerji, a subcutaneous infusion of liquid levodopa and carbidopa, for adults with Parkinson’s disease. In 2015, AbbVie gained FDA approval for the combination treatment, known commercially as Duopa. The Japanese company gained Onerji in a $1.1-billion acquisition of NeuroDerm in 2017.  Crinetics has won a CHMP endorsement for Palsonify for the treatment of acromegaly, a rare hormonal disorder that usually occurs in middle-aged adults and is caused by the pituitary gland producing excess growth hormone. The FDA signed off on the selectively targeted somatostatin receptor type 2 agonist in September of last year.Also making the grade with the CHMP is X4 Pharmaceuticals’ Xolremdi for WHIM syndrome, an ultra-rare hereditary condition in which the immune system does not work properly, making patients more susceptible to bacterial and viral infections. The FDA approved the first-of-its-kind treatment in 2024. 2 CHMP rejections Vanda Pharmaceuticals has been on a roll, gaining FDA approvals for two new drugs in the last two months. But the Washington, D.C.-based drugmaker has failed to make the grade with its atypical antipsychotic drug iloperidone. The CHMP has questioned its efficacy and safety, citing that iloperidone can cause a change in the heart’s electrical activity, which can lead to a “life-threatening heart rhythm abnormality.” The risk of using iloperidone outweighs the benefits of treatment, the CHMP said.Vanda was seeking approval for iloperidone as a treatment for schizophrenia and bipolar I disorder. It has been on the market in the U.S. as Fanapt since 2009. The CHMP also swatted back Acadia Pharmaceuticals’ Rett syndrome drug Daybu, questioning its efficacy. The FDA approved the treatment in 2023.