BioMarin has been criticized for licensing the drug on the basis of previously conducted research, and yet charging exorbitantly for it.[25] A group of UK neurologists and pediatricians petitioned to prime minister David Cameron in an open letter to review the situation.[26] The company responded that it submitted the licensing request at the suggestion of the French government, and points out that the increased cost of a licensed drug also means that it is monitored by regulatory authorities (e.g. for uncommon side effects), a process that was previously not present in Europe.[27] A 2011 Cochrane review compared the cost of the 3,4-DAP and 3,4-DAPP in the UK and found an average price for 3,4-DAP base of £1/tablet and an average price for 3,4-DAP phosphate of £20/tablet; and the authors estimated a yearly cost per person of £730 for the base versus £29,448 for the phosphate formulation.[28][29] Meanwhile, in Europe, a task force of neurologists had recommended 3,4-DAP as the firstline treatment for LEMS symptoms in 2006, even though there was no approved form for marketing; it was being supplied ad hoc.[23]:5[30] In 2007 the drug's international nonproprietary name was published by the WHO.[31] In the face of the 7 year exclusivity that an orphan approval would give to Biomarin, and of the increase in price that would accompany it, Jacobus began racing to conduct formal clinical trials in order to get approval for the free base form before BioMarin; its first Phase II trial was opened in January 2012.[32] In October 2012, while BioMarin had a Phase III trial ongoing in the US, it licensed the US rights to 3,4-DAPP, including the orphan designation and the ongoing trial, to Catalyst Pharmaceuticals.[33] Catalyst anticipated that it could earn $300 to $900 million per year in sales at peak sales for treatment of people with LEMS and other indications, and analysts anticipated the drug would be priced at around. $100,000 in the US.[17] Catalyst went on to obtain a breakthrough therapy designation for 3,4-DAPP in LEMS in 2013,[4] an orphan designation for congenital myasthenic syndromes in 2015[34] and an orphan designation for myasthenia gravis in 2016.[35] In August 2013, analysts anticipated that FDA approval would be granted to Catalyst in LEMS by 2015.[4] In October 2014, Catalyst began making available under an expanded access program.[36] In March 2015 Catalyst obtained an orphan designation for the use of 3,4-DAPP to treat of congenital myasthenic syndrome.[37] In April 2015, Jacobus presented clinical trial results with 3,4-DAP at a scientific meeting.[19] In December 2015 a group of 106 neuromuscular doctors who had worked with both Jacobus and BioMarin/Catalyst published an editorial in the journal, Muscle & Nerve, expressing concern about the potential for the price of the drug to be dramatically increased should Catalyst obtain FDA approval, and stating that 3,4-DAPP represented no real innovation and didn't deserve exclusivity under the Orphan Drug Act, which was meant to spur innovation to meet unmet needs.[17][38] Catalyst responded to this editorial with a response in 2016 that explained that Catalyst was conducting a full range of clinical and non-clinical studies necessary to obtain approval in order to specifically address the unmet need among the estimated 1500-3000 LEMs patients since about 200 were receiving the product through compassionate use – and that this is exactly what the Orphan Drug Act was intended to do: deliver approved products to orphan drug populations so that all patients have full access.[39] In December 2015 Catalyst submitted its new drug application to the FDA,[40] and in February 2016 the FDA refused to accept it, on the basis that it wasn't complete and in April 2016 the FDA told Catalyst it would have to gather further data.[41][14] Catalyst cut 30% of its workforce, mainly from the commercial team it was building to support an approved product, to save money to conduct the trials.[42] In March 2018 the company re-submitted its NDA.[43] The FDA approved amifampridine for the treatment of adults with Lambert-Eaton myasthenic syndrome on November 29, 2018.[44] In February 2019, U.S. Senator Bernie Sanders questioned the high price ($375,000) charged by Catalyst Pharmaceuticals for Firdapse.[45][46] In May 2019 the privately held US company Jacobus Pharmaceutical, Princeton, New Jersey gained approval by the FDA for amifampridine tablets (Ruzurgi) for the treatment of LEMS in patients 6 to less than 17 years of age.