Patent Office refuses application for AcelRX's Nanotab Sufentanil

Application failed to pass the test of Section 3(d)

The Indian Patent Office has refused a patent application of US-based AcelRx Pharmaceuticals, Inc a specialty pharmaceutical company focused on treatment of acute and breakthrough pain, for a nanotab sufentanil, to be administered below the tongue rather than swallowing a larger pill for relief. The Patent Office said that the claimed invention is not patentable under Section 3(d) of the Patent Act.

The company filed its patent application for Small-volume oral transmucosal dosage forms, on July 15, 2008 and the first examination report was issued on May 23, 2013.

It claims that the nano tablet to be administered sublingual with sufentanil and a bioadhesieve which reduces production of saliva, thus helping higher absorption rates of the medicine provided in the dosage form. If it is administered through gastrointestinal tract, a portion of the medicine would not be absorbed, it says. The dosage form of the nanotab has a volume of less than 30 microliter or a mass of less than 30 mg.

Considering the application, S Kundu, assistant controller of patents and designs, Kolkata, observed that the dosage form of particular volume is vital for the tablet to work in a particular route and not on sufentanil and the bioadhesive material as its constituents. To reduce the volume or mass of the dosage form is considered as an obvious solution to the skilled person for providing an alternative sufentanil dosage form for oral transmucosal administration with respect to the prior art. Hence no inventive step could be acknowledged.

The official said that the improved properties of the claimed invention provide advantages over the prior art in terms of bioavailability to known compounds by giving a particular shape and respect to dosage form, but it did not result in greater therapeutic efficacy.

"In order to pass Section 3(d)'s 'efficacy' requirement, 'substantial therapeutic efficacy' or a 'healing effect on the body' should be clearly shown. The efficacy shown therein does not show any superior therapeutic efficacy. Accordingly it fails to pass the test of section 3(d) of the Patents Act (as amended). Since the application did not qualify the test of inventive step and fails to pass Section 3(d) I do not think other matters need to be considered further," said Kundu.

Sufentanil is a well known synthetic opioid analgesic drug in the field of pharmaceutical chemistry approximately five to 10 times more potent than its parent drug, fentanyl, and 500 times as potent as morphine, says the order. The main use of this medication is in operating suites and critical care where pain relief is required for a short period of time. It also offers properties of sedation and this makes it a good analgesic component of anaesthetic regimen during an operation. It is usually administered through an intravenous route.