What's working and what isn't?

Sam Fazeli: The arrival of Covid-19 vaccines has put the focus of the pandemic fight on inoculating as many people as quickly as possible. But outbreaks are still raging worldwide, with thousands of new infections every day and health systems under pressure to care for the sick, a reality that will continue for some time. Vaccine timelines also keep getting more and more stretched. With that in mind, it's a good time to take stock of where we are in treating the disease. The short answer is, there's progress but it's mixed.

For months, Gilead Sciences Inc.'s remdesivir and the generic steroid dexamethasone have been used on the front lines after being shown to reduce hospital stays and improve recovery speeds. Now, as we learn more about Covid-19, more treatments - including some that at first drew skepticism from physicians and scientists - are proving effective in certain circumstances. Others, such as convalescent plasma, are not. Let's take a look:

"Toci": Two arthritis drugs that previously failed in treating Covid-19 - Roche Holding AG's tocilizumab and Sanofi-Regeneron Pharmaceuticals Inc.'s sarilumab - are now showing a meaningful effect in helping reduce the burden of disease in some patients. It seems that when the drugs are used is key. The latest data comes from a trial involving patients who were treated within 24 hours of needing hospital care in an intensive care unit. The drugs reduced mortality, suggesting that seven or eight lives would be saved for each 100 people treated. The hope is that this data will be corroborated in the U.K.'s much larger and pioneering Recovery trial now underway, with more than 3,000 of the 28,000 and rising participants treated with "toci." This will provide the most concrete data behind the drug and will potentially enable global approvals beyond Britain.

"Bam-bam": Next up are new drugs developed by Eli Lilly & Co. and Regeneron, part of a promising group of therapies called monoclonal antibodies that mimic the body's response to infection. Lilly's bamlanivimab, affectionately known as "bam-bam," was the first to gain emergency use authorization by the Food and Drug Administration. Both Lilly's and Regeneron's treatment have now been cleared for high-risk patients to help prevent hospitalization. One obstacle for adoption of these drugs has been the logistics of administering them - they need to be delivered using specialized infusion equipment.

This difficulty was compounded in bam-bam's case with a confusing efficacy story and lukewarm comments about it in the Covid-19 treatment guidelines from the National Institutes of Health, resulting in doses piling up on hospital shelves. This situation may be about to change, though, given an early read from a 2,000-patient Mayo Clinic study in which the use of bam-bam was shown to reduce hospitalizations and emergency-room visits by 70 per cent. There are also indications of a reduction in mortality. When data from this study is published, it is likely to drive increased interest in the use of bam-bam, and possibly Regeneron's antibody treatment, too. I do still remain cautious about the broad use of these drugs because of the risk they may hasten development of resistant mutations in the virus, which may, though unlikely, also impact vaccine-induced immunity.

Plasma: Convalescent plasma, a source of hope in the early days of the pandemic, has had a lot of subsequent failures and questions about its use. While not a drug per se, it is supposed to work in a similar way as monoclonal antibodies by giving patients ready-made immunity in a bottle in the form of plasma from recovered patients that is full of antibodies to the virus. The problem with previous attempts in showing a benefit from this approach was a lack of standardization and its use at the wrong time. Then recent data from a trial in Argentina raised hopes that if you use plasma with high amounts of antibodies early enough, when the infection itself is still active, it does make a difference.

Unfortunately, there's since been another setback, and this time a very serious one. The U.K.'s aforementioned Recovery trial has been comparing Regeneron's antibody treatment and convalescent plasma to standard care without those treatments in a very large patient group, making the data and its statistical analysis very robust. Findings released Friday from the trial showed no difference in the mortality of those receiving plasma and those on placebo. We still need to see the data in published form to be able to judge if there were any other potential explanations for the outcome.

But if the result is unequivocal, it at least means there will be no more time and money wasted treating patients with an ineffective therapy that carries some risks. In a way, the negative outcome is still a step forward in sharpening treatments of Covid-19.

The end of the pandemic may be in sight, assuming we can control infections and the development of new variants, but it's still many months away. Fortunately, the more we learn, the better we know which treatments are helpful and how to use them. The arsenal is growing. We can use all the help we can get. (Bloomberg)