My husband is at the hopsital at the moment on another trial. Paraxel gave the group their drug on Tuesday morning after the six men were taken into ICU. I can't believe they didn't stop all trails until they knew what went wrong. I'm so worried about my husband and can't wait for him to get home. Name and address withheld

For those of you who think animal testing and drug trials in general should be banned, I would love to hear what alternative you would suggest for developing life-saving medicines. I have read numerous posts wanting to shut down the "evil" drug companies and ban all animal and human research, but what do you suggest? I am alive today because of chemotherapy drugs that were tested vigorously in animals and other humans before I took them. I am eternally grateful for the animals and people who made it possible for me to exist today. Ken Singletary, Iowa city, Iowa

I have been conducting clinical drug trials since 1977 and I have lost count of the number of times over the past 29 years that I have volunteered and taken part in these studies. During that period the worst thing that has happened to me is a splitting headache. So HT [below], I and my colleagues do "try it ourselves". Apart from the numerous safeguards that are already in place, I would never undertake a study that I considered unsafe or that I would not be prepared to participate in myself or ask a family member or friend to take part in. This event is unprecedented and my sympathy is with the six volunteers and their families at this time. Atholl Johnston, London

To "name and address withheld" who had surgery in Cardiff: Did it work? If so, what are you complaining about? Aimee Sexton, Cardiff

As a doctor working in the pharmaceutical industry I am extremely disappointed at the way some of the media have covered these events. It is, without question, a tragedy for the six ill volunteers and those directly involved. However, there has been irresponsible reporting from the tabloids and news programmes such as BBC One's Six O'clock News, whose coverage largely consisted of an understandably hysterical girlfriend, and not an informative account of phase one trials and an attempt to put into context what has happened. Headline-grabbers such as "volunteers paid £2,000 now in intensive care" are misleading. Volunteers are given an inconvenience allowance for their time and the inconvenience that they have endured. They are not meant to be paid large sums of money as this could be coercive, and detract from the more altruistic reasons for participating, which we would hope for. PS. I wonder if those against animal testing will be volunteering to have new medicines tested on themselves instead? Name and address withheld

As more and more drugs are developed using these methods, the animal tests preceeding phase I will become more and more misleading, to the point of irrelevance. Jerry Breslin, Woburn Sands

Putting foreign, chemical, unnatural substances into your body has always struck me as unwise, I don't like medicine of any kind. At the height of my financial woes, I would eye the bright, enticing adverts and contemplate it, "just once, where's the harm in that" was the thought running through my head; my natural instinct of self-preservation prevented me from following through, however. Now I am so grateful that I did not. My heart goes out to those poor men and to their families. Sarah Marquis, London

Consulting the TeGenero website one finds that the experimental drug in question, TGN1412, is a "fully humanised super monoclonal antibody". This puts it into the same category as Herceptin, which starts out as an antibody raised in an animal, usually a mouse, which is then genetically-engineered to "humanise" it, thereby fooling the human immune system into thinking it is of the body's own making, thus avoiding instant rejection, and increasing its potency. It is only to be expected that a humanised antibody would have far greater potency in a human volunteer than in experimental animals. (The immune systems of these species would have recognised the antibody as a foreign protein, and would have begun to neutralise the foreign invader before it had time to do its intended job, in this case to stimulate killer T cells.) There are conflicting reports at present about the outcome of those preliminary animal trials. However, if adverse effects had been seen, as has been suggested, that would be a matter of great concern, and grounds for the trial organisers to proceed with extreme caution, given that any response would have been muted in those species. One wonders if Parexel showed an appropriate level of caution in the design of their test protocols when moving from animal to human trials. Those precautions would have needed to be especially stringent before allowing volunteers in off the street to be injected with a product specifically engineeered for potency in human beings, one which could not, for the reasons stated, be adequately tested beforehand for safety in animals. Colin Berry, Antibes, France

Never will I do this again. As HT said (below), why don't they try it on themselves? Simple, because it is very dangerous. I'm a woman of 51kgs and took part in a trial because I needed the cash. I was just one kilo over the minimum requirement for women (they should weigh at least 50) and the smiley people in the hospital encouraged me. I felt sick for two weeks after, weak, dizzy and as a result I now suffer panic attacks. My blessings to these young men in hospital. Name and address withheld

Thomas Hanke, chief scientific officer of TeGenero, last night refused at a press conference to say whether animals had died during earlier tests. “There has been no issue on the safety of the drug on animals. This is not relevant,” he said. So, why do we still carry out testing on animals if it has no relevance? Colleen Sellars, Lincoln

I took part in a Tamoxifen drugs trial 10-12 years ago at the Royal Marsen Hospital in London. I have been suffering side-effects ever since. The trial was to see if Tamoxifen could be used for preventing breast cancer in healthy women. I was curious to see if there were any other women out there who were on this drugs trial and see if they had suffered any similar ill-effects. Name and address withheld

It never ceases to amaze me that the first dose of an unknown agent is given to healthy volunteers (paid or otherwise). Oncology drugs are an exception being given only to patients. All human studies are approved by ethics committees. It is time for them to review the classes of drugs which it is ethical to give only to patients. Norma Rohde, Melbourne, Australia

Better a willing human, for whatever reason, than a poor dumb animal. Doesn't this case reinforce anti-vivisection? If it had been an animal who had suffered no one would have been aware and a large proportion of this sad world wouldn't have cared anyway. Thomas Garnell, Peacehaven