(Sharecast News) - London's FTSE 250 was up 1.61% at 17,773.08 in afternoon trade on Tuesday, as Indivior shook off a run of falls to lead the charge.Opioid addiction treatment specialist Indivior was the top riser as it bounced back from recent falls, having plummeted on the back of a defeat in a US court battle to prevent India's Dr Reddy's Laboratories from selling a generic version of its Suboxone addiction treatmentMeanwhile, oilers Tullow Oil and Premier Oil also climbed, accompanied by oil and gas engineering services provider Weir Group, as oil prices clawed back some of Monday's losses.UK private healthcare provider Spire Healthcare continued to advance on the back of an upgrade to 'overweight' at Morgan Stanley, while high street sportswear retailer JD Sports edged upward as Berenberg reiterated its 'buy' rating on the stock with a target price of 530p."While many see JD as a high-quality operator and success story in recent years, it was difficult to spark new enthusiasm for another UK store-based retailer (c70% group EBIT). This is harsh and misses the key opportunities. JD is enjoying exceptional momentum internationally - with Finish Line offering substantial potential upside. Both, we believe, are underappreciated by the market," it said.Superdry suffered the heaviest losses on the index as Berenberg cut its stance on the stock to 'hold' from 'buy' a day ahead of the retailer's interim results, also cutting the price target to 950p from 1,200p following an "annus horribilis" for the group.Liberum also slashed its price target on the 'hold'-rated retailer to 700p from 900p, saying it was "time for a strategy rethink".High-interest lender Amigo Holdings fell after it appointed Nayan Kisnadwala as its new chief financial officer, succeeding Simon Dighton, who will step down by the end of the year.Finally, gold miner Centamin crept downward as the pound made gains thanks to strong jobs data after Theresa May's decision to call off this week's parliamentary vote on Brexit sent the currency crashing to its lowest level in almost two years. FTSE 250 - RisersIndivior (INDV) 84.43p 10.31%Computacenter (CCC) 1,027.27p 6.34%Playtech (PTEC) 407.10p 6.29%NewRiver REIT (NRR) 219.50p 6.04%Spire Healthcare Group (SPI) 113.40p 5.88%Tullow Oil (TLW) 187.90p 5.59%Kier Group (KIE) 396.30p 5.29%Weir Group (WEIR) 1,408.50p 5.19%Premier Oil (PMO) 74.40p 5.08%JD Sports Fashion (JD.) 370.80p 4.89%FTSE 250 - FallersSuperdry (SDRY) 572.50p -7.44%Stagecoach Group (SGC) 148.78p -5.05%Amigo Holdings (AMGO) 255.03p -4.34%Bakkavor Group (BAKK) 138.00p -4.17%Hochschild Mining (HOC) 159.50p -2.77%CLS Holdings (CLI) 207.00p -2.13%Saga (SAGA) 100.60p -2.04%Convatec Group (CTEC) 144.60p -1.83%St. Modwen Properties (SMP) 384.60p -1.54%Centamin (DI) (CEY) 101.95p -1.31%