Merck & Co’s earnings have leapt for the fourth quarter, helped by the contribution of recently-acquired Schering-Plough, and has become the latest drugmaker to announce major job cuts.

Net income came in at $6.49 billion, up from $1.64 billion in the like, year-earlier quarter, thanks to a $7.50 billion pretax gain relating to the S-P acquisition. Revenues shot up 67% to $10.09 billion, helped by two months-worth of sales from the newly-acquired company.

Merck’s best-selling treatment was once again the asthma/allergic rhinitis drug Singulair (montelukast), which rose 12% to $1.26 billion, while revenues from the antihypertensives, Cozaar (losartan) and Hyzaar (losartan plus hydrochlorothiazide) were up 8% to $955 million. However the firm noted that this figure will suffer “a significant decline” since there are “multiple sources of generics expected” for these medicines when both lose marketing exclusivity in the USA in April and in major European markets during the first quarter.

Combined sales of the cholesterol drugs Vytorin (ezetimibe plus simvastatin) and Zetia (ezetimibe) were up some 6% to $1.19 billion. The diabetes drug Januvia (sitagliptin) performed very well, generating $558 million in the quarter, up 35%, while Janumet (sitagliptin plus metformin) brought in $760 million, a leap of 43%. Turnover from the HIV drug Isentress (raltegravir) reached $234 million, up 80%, while sales of the cervical cancer jab Gardasil slipped 3% to $277 million.

As for S-P’s products, the anti-inflammatory Remicade (infliximab), the Johnson & Johnson drug which S-P sells outside the USA, contributed $431 million over two months, while the anti-allergy medication Nasonex/Asmanex (mometasone) brought in $165 million.

Sales of the brain cancer drug Temodar (temozolomide) reached $188 million, while the hepatitis C treatment PegIntron (pegylated interferon) brought in $149 million. The antihistamine Clarinex (desloratadine) had sales of $101 million, while Follistim/Puregon (follitropin beta), a fertility treatment, contributed $96 million nad turnover of the contraceptive Nuvaring came in at $88 million.

Chief executive Richard Clark said “the new Merck is off to an excellent start”, saying that the firm is “making great progress on integration”. He added that “each of our top 10 selling brands from an expanded product portfolio exceeded $1 billion in annual sales” and “we stand firmly behind the financial targets we provided at the time of our initial merger announcement”, ie high single-digit earnings growth through to 2013.

Merck also announced the first phase of restructuring after the merger which should yield savings in 2012 of $2.6-$3.0 billion. This will see its 100,000-strong workforce reduced by 15% “across all areas of the combined company worldwide”. The company also plans to eliminate 2,500 vacant positions, noting that the reductions will primarily come from “the elimination of duplicative positions in sales, administrative and headquarters organisations”.

Merck concluded by saying that an ongoing reevaluation of manufacturing and R&D facilities worldwide have not yet been completed and it will continue to hire new employees “in strategic growth areas”. The pretax cost of the restructing will cost $2.6-$3.3 billion.