The S&P/ASX 200 Index (ASX: XJO) is on form again and pushing higher on Tuesday. In afternoon trade, the benchmark index is up 0.2% to 7,870.2 points.

Four ASX shares that are rising more than most today are listed below. Here's why they are climbing:

Clarity Pharmaceuticals Ltd (ASX: CU6)

The Clarity Pharmaceuticals share price is up 11% to $2.83. Investors have been buying this pharmaceutical company's shares despite there being no news out of it. However, it is worth noting that its shares have been sold off recently, so this could be a case of bargain hunters swooping in today. In fact, Clarity Pharmaceuticals' shares are still down 30% since the start of the year. Bell Potter is likely to see this as a buying opportunity. It recently put a speculative buy rating and $5.20 price target on its shares.

New Hope Corporation Ltd (ASX: NHC)

The New Hope share price is up 9% to $4.03. This morning, this coal miner released its half year results and revealed a 22% increase in underlying EBITDA to $517.3 million and a 35% jump in net profit after tax to $340.3 million. This allowed the New Hope board to reward its shareholders with a fully franked interim dividend of 19 cents per share. This is up 11.8% from 17 cents per share a year ago. In addition, the company announced a $100 million on-market share buyback.

Orthocell Ltd (ASX: OCC)

The Orthocell share price is up 7% to $1.47. This has been driven by the release of a positive announcement from the regenerative medicine company this morning. Orthocell revealed that Singapore's Health Sciences Authority (HSA) has granted regulatory approval for its market leading dental membrane, Striate+. This is for use in guided bone and tissue regeneration applications. This is a big positive as Singapore is seen as a strategic regulatory market and can be used as a stepping stone to approvals in other ASEAN markets.

West African Resources Ltd (ASX: WAF)

The West African share price is up 4.5% to $2.34. Investors have been buying this gold miner's shares following the release of an update on its Sanbrado gold production centre in Burkina Faso. According to the release, the company has achieved positive results in respect to resource estimation and scoping studies for a potential underground development beneath the Toega open pit at the production centre. Management estimates that 515,000 ounces gold could be added to Toega's life-of-mine production over its seven year mine life.