The chances of an inhaled insulin hitting the market have improved after regulators in the USA accepted the resubmission of MannKind Corp’s Afrezza after having rejected the therapy a few months ago.

In March, the US Food and Drug Administration issued a complete response letter regarding the New Drug Application for Afrezza, requesting additional information. Now MannKind has provided clinical data from a recently-completed efficacy study in patients with type 1 diabetes as well as updated pooled safety data related to Afrezza and information on the comparability of the company’s next-generation delivery system to the device, called the MedTone inhaler that was used in Phase III studies.

The FDA has accepted the file and classified it as a class 2 resubmission, which means that Afrezza will be reviewed within six months or so. Indeed, MannKind now has a Prescription Drug User Fee Act action date of December 29.

Chief executive Alfred Mann said the firm has worked diligently since March to prepare the resubmission “and we are confident that we have addressed the requests that were outlined by the FDA”. He added that MannKind will continue to work closely with the FDA “during this final stage of the review process [and] we firmly believe Afrezza has the potential to address a poorly-met need in diabetes therapy”.

Rodman & Renshaw analysts Simos Simeonidis and Yatin Suneja issued a research note saying that acceptance of a resubmission “means very little (actually nothing) in terms of an application’s chances of being approved”. However, they added that “we see today’s news as an incremental positive”. Given that the company was able to submit its response to the FDA in a matter of two-three weeks after meeting with the regulator, “the bear theory that the agency may have requested new, longer trials seems to lose even more ground”.

In addition, Messrs Simeonidis and Suneja said “it is good to see the company meet and actually deliver earlier than expected for a change on a guided timeline”. They now expect that the company will re-engage in discussions with partners “but we view the importance of the timing of a partnership as secondary; we believe that the most important questions for investors are whether Afrezza gets approved or not, and whether it gets partnered or not….and we remain bullish on the outcome of both”.

Observers have expressed concern about inhaled insulin as a viable treatment. In recent years, Eli Lilly and diabetes specialist Novo Nordisk have abandoned the field and in October 2007, Pfizer pulled its inhaled insulin therapy Exubera after it failed to make any impact in the diabetes market.

However the analysts conclude that "Afrezza should not be bundled together with Exubera et al as just another inhalable insulin, but that it is a 'better' insulin that just happens to be delivered via inhalation.

Rodman & Renshaw believes that in the long-run, Afrezza “has the potential to become a multi-billion dollar product” and investors seem pretty enthusiastic too. MannKind’s shares ended the day up 7.6% at $6.68.