Adamis has called its generic version Symjepi, and like EpiPen, it is supplied in a pack of two syringes for emergency treatment of type 1 allergic reactions including anaphylaxis.

Each prefilled syringe contains 0.3mg of the hormone, but Adamis is already boasting that its device is more convenient than Mylan’s blockbuster.

Symjepi is smaller than EpiPen and will be easier to fit in a pocket or purse – making the product more patient friendly as well as lower in price.

Adamis said the drug will be a "low-cost" alternative to EpiPens, and according to press reports will be sold at a lower cost than Mylan’s own "branded generic" EpiPen.

At full price, EpiPens cost up to $700, although the generic version costs between $225 and $425.

Also on the horizon is a "junior version" of Symjepi, which would contain a lower epinephrine dose and compete with Mylan’s EpiPen Jr.

Sales of EpiPen have fallen in the wake of last year’s pricing scandal, which saw the company’s CEO Heather Bresch grilled by politicians over the high price of the product.

Mylan’s own branded generic has taken most of the market share from EpiPen, and while there are a few other alternatives, investors clearly think that Adamis is on to a winner.

Shares in Adamis went up 53% following the announcement, from just under $4 to nearly $6, with further gains in after-hours trading.

Adamis CEO Dennis Carlo said: "With an anticipated lower cost, small size and user-friendly design, we believe Symjepi could be an attractive option for a significant portion of both the retail (patient) and non-retail (professional) sectors of the epinephrine market."