Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

The Synairgen share price has rocketed 500% in two days! Here’s what I’d do now

The Synairgen share price (LON:SNG) has had a storming two days following positive results on a potential treatment for coronavirus. Should new investors go all-in?

| More on:

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

Yesterday, respiratory drug developer Synairgen (LSE: SNG) jumped an astonishing 420% in value. It’s up another 15% this morning. Could there be even more to come? Quite possibly. That said, I think anyone investing should keep their expectations in check.

Before explaining why, let’s have a recap.

What’s behind Synairgen’s rise?

Monday’s share price jump followed news of a successful trial of a treatment. labelled SNG001 (an inhaled dosage of interferon beta), in patients who had been hospitalised as a result of coronavirus.

Results showed those who received the drug in a double-blind trial (where neither the patient nor the clinician knows who is getting what) had a 79% lower risk of severe disease compared to those who received the placebo. Those on SNG001 were also more than twice as likely to recover than those who didn’t receive the drug.  

With concerns that the arrival of winter could bring about a fresh wave of the coronavirus, news that the treatment helps the lungs to tackle the virus, even in the event of co-infection (e.g. if a person catches flu), is clearly very positive. 

Can the share price keep rising?

Here, from an investment point of view, is where things get tricky.

What’s important to remember — and the company clarified today — is that the recent positive outcome was a Phase 2 trial. This phase is “designed to test the efficacy of a drug and takes place before the drug is approved or able to be marketed.” In other words, a lot of questions still need answering.

While positive that patients in both groups were matched with each other in things like age, this trial involved just 101 patients — a very small sample. Also, all were recruited in the UK, which means results might not be generalisable to other countries.

Nor did every finding from the trial reach statistical significance. In other words, we can’t be absolutely sure that what was found wasn’t just down to luck. Naturally, all this makes a much larger trial of the treatment (Phase 3 of drug development) absolutely essential. 

In short, I think SNG001 is still far from the sure thing the market presumably now believes it to be. For me, this has implications for what the Synairgen share price will do next.

The problem is that not everyone will want to stick around for the ride. It will, after all, be a few weeks before the company is ready to reveal the outcome of further analyses. If I were a trader and knew this, I’d seriously consider banking some profit on Synairgen.

And if I were a Foolish investor buying stocks for the long term (and I am), I’d be sure to appreciate that some in the market work on much shorter timescales and act (or not act) accordingly.

Buyer beware

Synairgen could certainly still reward those buying in now. However, I would caution anyone against thinking they can make easy money in a set period of time. It’s very easy to find examples of promising treatments that failed to live up to the initial hype and progress beyond Phase 3.

We must not allow our desire for a quick profit to override our true tolerance for risk. If you’re going to expect anything from the share price, expect volatility. Don’t bet the ranch and ensure you’re diversified elsewhere.

Paul Summers has no position in any of the shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Young woman holding up three fingers
Investing Articles

Want to start investing in 2026? 3 things to get ready now!

Before someone is ready to start investing in the stock market, our writer reckons it could well be worth them…

Read more »

Investing Articles

Can the stock market continue its strong performance into 2026?

Will the stock market power ahead next year -- or could its recent strong run come crashing down? Christopher Ruane…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Here’s how someone could invest £20k in an ISA to target a 7% dividend yield in 2026

Is 7% a realistic target dividend yield for a Stocks and Shares ISA? Christopher Ruane reckons that it could be.…

Read more »

A quiet morning and an empty Victoria Street in Edinburgh's historic Old Town.
Investing Articles

How little is £1k invested in Greggs shares in January worth now?

Just how much value have Greggs shares lost this year -- and why has our writer been putting his money…

Read more »

Businessman using pen drawing line for increasing arrow from 2024 to 2025
Investing Articles

This cheap FTSE 100 stock outperformed Barclays, IAG, and Games Workshop shares in 2025 but no one’s talking about it

This FTSE stock has delivered fantastic gains in 2025, outperforming a lot of more popular shares. Yet going into 2026,…

Read more »

Close-up of British bank notes
Investing Articles

100 Lloyds shares cost £55 in January. Here’s what they’re worth now!

How well have Lloyds shares done in 2025? Very well is the answer, as our writer explains. But they still…

Read more »

Thoughtful man using his phone while riding on a train and looking through the window
Investing Articles

How much do you need in an ISA to target £2,000 a month of passive income

Our writer explores a passive income strategy that involves the most boring FTSE 100 share. But when it comes to…

Read more »

Investing Articles

£5,000 invested in a FTSE 250 index tracker at the start of 2025 is now worth…

Despite underperforming the FTSE 100, the FTSE 250 has been the place to find some of the UK’s top growth…

Read more »