A US FDA review panel has recommended that Afrezza be approved and concluded that the technology used to deliver MannKind's inhalable insulin does not damage airways or lung cells.
The Endrocinologic and Metabolic Drug Advisory Committee reccommended that Afrezza be approved for the treatment of patients with Type I and II last night after its third assessment of the product.
Since then coverage has focused on Afrezza's revenue potential , which is understandable given MannKind’s mounting losses, $53.6m in Q4 2013, and the fact the drug is the firm's only product.
Other reports have concentrated on the drug's long-term safety profile in light of revelations about Pfizer's failed inhaled insulin, Exubera , which was linked to elevated lung cancer risk after it was pulled from the market.
Such speculation is likely to continue until the US Food and Drug Administration (FDA) makes its final decision on Afrezza on April 10.
In contrast, the implications of the FDA Committee's approval recommendation for the delivery technology – Technosphere – used to get Afrezza deep into the lungs have received little attention.
The core of the Technosphere technology is the excipient fumaryl diketopiperazine (FDKP), which MannKind sources from an unnamed ‘major’ chemical supplier with plants in Europe and North America. The firm also has capacity to make the excipient at its facility in Danbury, Connecticut.
In Afrezza, FDKP, water and the non-ionic surfactant polysorbate 80 are mixed and crystallised into uniform particles of 2 microns in diameter in combination with recombinant human insulin.
FDKP is highly soluble at pH 6.0 – the prevailing physiological pH in the lungs – meaning that when the Afrezza particles have reached their destination the excipient dissolves and allows the insulin to be rapidly absorbed.
According to the FDA review document released yesterday any “absorbed FDKP is not metabolized and is excreted intact, primarily in the urine. The FDKP in the small fraction of swallowed powder is excreted intact in the faeces."
The panel also concluded that: “FDKP does not facilitate drug absorption, does not compromise the integrity of airway epithelial tight junctions or damage cell membranes but functions solely as the particle matrix to carry the insulin to the lung.”
MannKind underlined its desire to license out the Technosphere technology whether Afrezza ia approved or not in an annual report filed with the US Securities and Exchange Commission (SEC) this month.
"Afrezza utilizes our proprietary Technosphere formulation technology; however, this technology is not limited to insulin delivery...We are actively exploring opportunities to out-license our proprietary Technosphere formulation technology…Currently, we are actively working with several parties to assess the feasibility of formulating different active ingredients on Technosphere particles.”
On its website MannKind says it has already successfully tested Technosphere for the delivery of anionic and cationic drugs, hydrophobic and hydrophilic drugs, proteins, peptides, and small molecules to the lungs.
The California, US-based firm also says the system has the potential for application in other administration routes, although it does not provide additional details.
MannKind did not respond to a request for comment.