The drug, which is delivered intravenously once every three weeks, also improves the quality of life for patients compared with other treatments and reduces the side effects.
Richard Erwin, general manager at Roche, said: "Close collaboration between Roche, NHS England and NICE has resulted in NICE recommending Kadcyla as a cost-effective treatment". As per the reports from Cancer Research UK, there are 55,000 new cases of breast cancer annually and almost 10,000 deaths occur from this dreaded cancer each year.
Ms Longson added: "Since we started reassessing the drugs available through the Cancer Drugs Fund, companies have responded positively and shown that they can offer good deals when it comes to pricing".
The confidential agreement has also been endorsed by the National Institute for Health and Care Excellence (NICE), which rejected routine use of the drug in December previous year as it was deemed too expensive. Kadcyla or Traztuzumab emtansine, is useful in patients with HER2-positive tumors which have spread to other parts of the body from the breast and is now at a stage where operating it out is not possible. HER2 is a protein that makes breast cancer cells grow and can make breast cancer more aggressive.
"NHS England is also taking practical action to drive greater value from taxpayers growing investment in modern drug treatments, and that work is beginning to bear fruit. This has meant that we have been able to recommend these drugs for routine funding, which is clearly very good news for both patients and the NHS".
Campaigners had urged Roche to drop the price of the drug and more than 115,000 people signed a petition calling for NICE's provisional rejection of Kadcyla to be overturned. About 1,200 patients in England could benefit from the drug.
Before the election I campaigned for the Breast Cancer drug Kadcyla to be made routinely available on NHS. The decision prompted anger over a restrictive drug approval policy in England, particularly when Kadcyla was approved for use in Scotland in April. Breast Cancer Care described NICE's U-turn as "monumental".
Baroness Delyth Morgan, the charity's chief executive, said: "This is exceptionally good news for so many breast cancer patients. Today's landmark decision bodes well for patients looking for reassurances that modern cancer treatments can get through to NHS patients more quickly and can bring transformational improvements in patient outcomes for the future".
The company's United Kingdom general manager Richard Erwin welcomed the new deal as a "positive" development on Thursday.