By Karen Allen
BBC Health Correspondent
The parents of a young woman with the brain disease vCJD have persuaded government researchers to consider the drug their daughter is taking.
Holly was diagnosed with vCJD 18 months ago
Data on the impact of Pentosan Polysulphate will now be collected by the Medical Research Council.
The move follows criticism from Peter Mills, whose daughter Holly, 19, has been taking the drug for months.
He was angry the drug was not included in the MRC's only vCJD drug trial even though it may be helping his daughter.
Mr Mills broke his silence on Tuesday more than 18 months after Holly was diagnosed.
Legal restrictions had previously stopped him from speaking - but the BBC secured changes in an injunction.
There is no cure for variant CJD and the vast majority of people who have developed the disease have died.
But, behind the scenes, Pentosan Polysulphate, or PPS, is being used by patients.
The drug, licensed in tablet form to treat bladder problems, is injected directly into the patient's brain.
It is not a wonder drug but a therapy that might buy patients more time.
Up until now, legal restrictions have prevented families from speaking out.
But on Tuesday Mr Mills, whose daughter Holly has been on the drug for 15 months, said the fact the drug had been excluded from the trial meant that vital information about the disease was being lost.
The BBC understands that at least eight patients are receiving PPS and none appears to have suffered the devastating side effects that had initially been feared.
Holly before she fell ill
The MRC has issued a statement saying that it is in discussion with the families of those taking PPS and has invited them to a meeting later this month.
"The MRC did not originally include Pentosan in the trial because the Committee on the Safety of Medicines advised that there was insufficient information to form a rational basis for presenting Pentosan for a treatment.
"At the request of the Chief Medical Officer we are now ready to collect data about Pentosan."
Until now the MRC has focused on another drug, Quinacrine. However, the MRC told the BBC that out of six patients approached since it began a trial last autumn, only one has been recruited.
Earlier, Mr Mills told the BBC: "We want to see more research done on Pentosan and its effects.
"We are not against any other therapies, we just believe that this therapy should be included."
The High Court gave the go-ahead for the first patient with vCJD to undergo treatment with PPS in December 2002.
That patient, Jonathan Simms is now the longest surviving with vCJD.
Holly Mills was the second patient to receive the drug.
The BBC understands that at least eight patients are on the same therapy.
However, neither the medical staff or hospitals offering the treatment can be identified for legal reasons - and there appears to have been no legal mechanism to ensure the medical authorities collect information on the patients.
In both the cases of Holly Mills and Jonathan Simms, PPS seems to have slowed the progress of the disease.
But without thorough research it is not clear whether this is the normal course of vCJD, about which so little is known, or some effect of the drug.