Trastuzumab emtansine, sold as Kadcyla and made by Roche, can cost more than £90,000 per patient, according to the National Institute for Health and Care Excellence (NICE).
The organisation is currently appraising Kadcyla for patients with HER2-positive breast cancer that has metastasised, or spread to other parts of the body, cannot be removed by surgery, and has stopped responding to initial treatment.
Despite its effectiveness, Kadcyla "does not work well enough to justify its high cost and it therefore should not be recommended for routine NHS use", says draft guidance, published by NICE.
"We had hoped that Roche would have recognised the challenge the NHS faces in managing the adoption of expensive new treatments by reducing the cost of Kadcyla to the NHS," said Sir Andrew Dillon of NICE.
"This drug is already being funded through the special Cancer Drugs Fund. Our job is to recommend whether it should transfer into the NHS budget. We are very aware of the importance that people place on life-extending cancer drugs and a decision not to recommend a cancer treatment for routine NHS funding is never taken lightly."
He added: "We apply as much flexibility as we can in approving new treatments, but the reality is that given its price and what it offers to patients, it will displace more health benefit which the NHS could achieve in other ways, than it will offer to patients with breast cancer."
He is still holding out hope that Roche "will act in the best interests of patients and use this consultation period to look again at their evidence and consider if there is more they can do".
Campaigners said the decision suggested that the NICE assessment process was failing.
Dr Caitlin Palframan, of Breakthrough Breast Cancer, said: "Drug development and research is moving at a pace that the system can't seem to keep up with.
"We are now looking to the Department of Health and the pharmaceutical industry to find a way to work together to bring the cost of expensive drugs down and put a sustainable system in place by which new treatments can be made available on the NHS on a routine basis.
"Until then it appears NICE will be forced to reject these cutting-edge treatments, some of which are capable of providing women facing terminal breast cancer diagnoses with extra time with their loved ones, which is the very least they deserve."
The doctors were alleged to have signed blank forms used to give women access to abortions.
Anti-abortion campaigners say the forms are being used to flout abortion law, which requires two doctors to give support to a woman's request for an abortion.
The doctors are reported to have been identified in a Care Quality Commission investigation, launched after reports of doctors offering women abortion "without questions," even when the procedure was being used to select the sex of the child.
Their names were passed to the General Medical Council for investigation.
According to the Daily Mail, the GMC has decided to take no further action against any doctors for signing blank forms.
It obtained details of the decisions using Freedom of Information requests.
The paper quotes Jim Dobbin, Labour MP for Heywood and Middleton, as saying: "This is clear evidence of the abortion-on-demand culture throughout the medical establishment.
"Sixty-seven doctors happily referred for abortions without knowing a single thing about the woman requesting them.
"Worse, at the very top, senior doctors and lawyers at the GMC decided to keep these crimes to themselves. This shames the GMC and makes a mockery of the Abortion Act."
Laboratory studies have shown the male hormone is critical to the development of the stem cells that produce the hormone in adult males.
The Edinburgh University researchers say this could be a key factor in male health - with low hormone levels contributing to obesity, diabetes and heart disease.
Their study centred on the origins of Leydig cells, which produce the hormone in men.
They reported their findings in the Proceedings of the National Academy of Sciences last night.
The researchers say the level of testosterone in the womb might be influenced by the mother's lifestyle and any drugs or chemicals she was exposed to.
Researcher Professor Richard Sharpe said: "There is increasing evidence that a mother's diet, lifestyle and exposure to drugs and chemicals can have a significant impact on testosterone levels in the womb.
"We need a better grasp of these factors so that we can give reliable advice to pregnant women to protect the health of her unborn child."
K.R Kilcoyne et al. Fetal programming of adult Leydig cell function by androgenic effects on stem/ progenitor cells. PNAS 21 April 2014. [abstract]
Stroke is a top cause of death and disability. The form of stroke known as acute ischemic stroke is best treated with intravenous thrombolysis (clot-busting) drugs, usually a form of tissue plasminogen activator.
Time taken to begin thrombolysis is crucial for patient outcomes, explain Dr Martin Ebinger of Charite-Universitatsmedizin Berlin, Germany, and colleagues in the Journal of the American Medical Association today (23 April).
They investigated whether starting thrombolysis in a specialised ambulance can reduce delays. They compared this approach against usual care for 6,182 male and female stroke patients in Berlin, with an average age of 74 years.
Half were treated in an ambulance equipped with a "point-of-care laboratory", members of a specialised stroke team, and a CT scanner to rule out brain haemorrhage. If ischemic stroke was confirmed, thrombolysis was started before reaching hospital.
"Alarm-to-treatment time" was cut by 25 minutes when using the specialised ambulance. The rate of tissue plasminogen activator treatment was higher when the specialised ambulances were deployed - 33% versus 21%. Neither brain haemorrhage or seven day mortality were increased due to the specialised ambulances.
The team conclude: "Compared with usual care, the use of ambulance-based thrombolysis resulted in decreased time to treatment without an increase in adverse events."
They add that further studies are needed to assess the impact on clinical outcomes, and the benefits found in this study must be weighed against the higher costs of the specialised ambulances - about 832,000 UK pounds each.
Ebinger, M. et al. Effect of the Use of Ambulance-Based Thrombolysis on Time to Thrombolysis in Acute Ischemic Stroke: A Randomized Clinical Trial. JAMA 23 April 2014; doi:10.1001/jama.2014.2850