Pharmaceuticals and biotechnology stocks were rising by an average of six per cent in London on Tuesday, helped by a wave of high-profile M&A deals across the global healthcare sector.Leading the charge in the UK was AstraZeneca on reports that it could be at the centre of the largest deal in pharmaceutical history.Shares were up 7% in afternoon trade after The Sunday Times said that Pfizer could make a takeover approach valuing the group at £60bn. This is a 25% premium to the recent share price and would represent the largest foreign takeover of a UK business on record.While Astra is reported to have rejected an initial offer, analysts at Citigroup said Pfizer is likely to "push aggressively ahead with a second approach".Meanwhile, GlaxoSmithKline (GSK) jumped after announcing a massive three-part deal with Swiss pharmaceuticals peer Novartis, which will see shareholders receive a £4bn capital return.Under the proposed transaction GSK and Novartis are to create a new consumer healthcare business, GSK will acquire Novartis's vaccines business for $5.25bn, and Novartis will buy GSK's oncology portfolio for $16bn.Meanwhile over in the States, Botox maker Allergan is subject to a $47bn takeover offer from Valeant Pharmaceuticals, and Eli Lilly announced that it would buy Novartis's animal health division for $5.4bn in cash.The increased M&A activity gave stocks across the sector a boost today, including Hikma, BTG and NMC Health.Shire was also making strong gains after Jefferies raised its target price for the group, saying that the recent share-price weakness has presented an "attractive buying opportunity". The broker lifted its target for the shares from 3,400p to 3,550p and kept a 'buy' rating.Jefferies actually trimmed its estimates for Shire slightly due to "sluggish" first-quarter ADHD prescriptions trends in the States, but said it still believes earnings will increase at a "robust" compound annual growth rate of 13% over 2013-2018. Top performing sectors so far todayPharmaceuticals & Biotechnology 12,439.17 +5.99%Industrial Metals & Mining 1,196.37 +4.13%Industrial Transportation 3,110.46 +2.36%Electronic & Electrical Equipment 4,269.48 +1.99%Food & Drug Retailers 3,840.40 +1.86%Bottom performing sectors so far todayBC