The monkeypox treatment and what's coming: A conversation with the CEO making Tpoxx
Phil Gomez, CEO of Siga Technologies, is having a busy summer.
His company, which makes the only available monkeypox treatment, has been preparing for this moment for the last decade, working with a team of suppliers and ramping up just ahead of the outbreak — hoping that it would never have to deploy its treatment.
First approved in 2018 for smallpox, and known as Tpoxx or tecovirimat, the FDA didn’t initially extend the approval to monkeypox because the company didn’t run a trial prior to the current outbreak even though a trial could’ve theoretically been done.
Still, next week, the US plans to ramp up shipments of the drug and send out 55,000 doses to states and other jurisdictions, which is more than double the current supply.
So what should people expect in terms of accessing this treatment? Is the clinical trial data coming? And who’s making the decisions around the current distribution? Read below a lightly edited phone interview with Gomez from Friday morning.
Endpoints: Can you help me understand the math better — if there are about 13,000 confirmed cases by the CDC, and the US says it’s shipping out 55,000 doses of Tpoxx beginning next week — shouldn’t everyone who wants the antiviral get access to it?
Gomez: I’ll have to defer to the CDC and FDA on how they’re doing it. It wasn’t clear to me that they’ve changed the criteria on who would receive the doses, and it sounded like [they] said they will still focus on providing Tpoxx to high-risk patients. But by pre-positioning more courses, they will be able to more rapidly get courses to patients.
Endpoints: Is the plan still to ramp up to about 600,000 courses of Tpoxx per year, and are you working with contract manufacturers to ramp up production?
Gomez: There are 1.7 million doses of Tpoxx in the Strategic National Stockpile, so we delivered those beginning in 2013, and started delivering more in 2020 — so there is still a substantial amount in the SNS. In terms of the CMOs, Siga works with WR Grace and Co. on the active ingredient, Catalent for encapsulation, PCI for packaging, and Powdersize [a Lonza subsidiary] micronizes and tests API for use.
Endpoints: The NIH next month is about to kick off a placebo-controlled monkeypox trial in the US, funded and sponsored by the NIH. Can you talk about Siga’s involvement in the trial?
Gomez: We’re supporting 10 randomized-controlled trials around the world via government public health agencies, and we provide drug, placebo and expertise, and the good news is these protocols have been shared broadly across the US, Canada, UK and EU. So we’re hopeful wherever the outbreak goes, we’ll have an opportunity to rapidly collect data and file that in the US and Canada.
We have approval in the UK and Europe for monkeypox, but the NIAID trial would ultimately allow us to support a US approval for Tpoxx in monkeypox. From a high-level perspective, these outpatient trial protocols will look at the resolution of symptoms, with a secondary endpoint of reducing viral load. If anyone progresses to severe disease, they would be unblinded and switched to active drug.
Endpoints: How would you compare this trial to the Covid-19 vaccine and drug trials from earlier in the pandemic?
Gomez: It’s very different than a Covid vaccine trial because it’s just looking at symptoms resolving, which usually only last three to four weeks and Tpoxx will potentially shorten that. With hopefully hundreds enrolled, these trials should be much more rapid than the vaccine trial, but it will depend on the outbreak and where people are enrolled.
Endpoints: US government officials have distributed about 22,000 doses of Tpoxx so far. Any idea what the data have shown in terms of the treatment working?
Gomez: We haven’t gotten back any real-world evidence from the CDC yet, so I defer to them. Broadly, we’ve been actively collecting data on monkeypox, there were data from the UK published last year, there’s been compassionate use treatment in the Central African Republic, and there’s another RCT that we’ve set up alongside NIAID in the Democratic Republic of Congo before the current outbreak.
The FDA said in 2018 that when we won approval for smallpox, that we couldn’t win one for monkeypox per the Animal Rule because we could’ve run a trial in the DRC. But the FDA has also said the DRC clade is different from the current one, so now, with the broad outbreak, unfortunately, the opportunity is to collect the real world data.
Endpoints: The decision to use an expanded access program to distribute Tpoxx — was that a decision Siga made? And any plans to move Tpoxx into the commercial market?
Gomez: The CDC made that decision. The drug was developed for smallpox and we’ve only ever sold it to governments. So we have not looked at the commercial sales channels, but we certainly now are working to evaluate and plan to put it through the commercial market, but that will take time. We’re looking at the RCT data as an inflection point for that.
Endpoints: Did you push back against the idea of using an expanded access program to distribute Tpoxx?
Gomez: They [the CDC] have the product in the SNS so they control it. We don’t have a lot of input on that.
Endpoints: And HHS yesterday announced the formula by which states and jurisdictions would be allocated Tpoxx — did you work with HHS on that formula?
Gomez: Yesterday was the first time I saw it. The drug is in the SNS. I think we’re viewed more as a supplier.
Endpoints: What can you say about the supply and demand of Tpoxx worldwide — given that it’s so difficult to find in the US, is there a shortage right now? And can you meet the growing demand?
Gomez: This is a question we look at every day. I think most public health organizations saw the initial outbreak and thought it wouldn’t be so deadly, so they took a let’s wait-and-see approach. Then in the next phase, as cases started to grow, countries bought small supplies to treat the current outbreak, and we’ve been working predominantly in that space, and have $60 million in international orders of product.
We’re now in the next phase which is where can see this outbreak go, and what might we need over the next year or two, and that’s evolving and we have product available but we don’t know where it will go.
If millions and millions of courses are needed, we will need to radically rethink our supply network and expand it. But we just don’t know where it goes.
To provide context: In 2020 and 2021, we delivered about 363,000 courses to the US government, and we anticipated delivering that next year and the year after, so we anticipated a lot of deliveries over the next few years, and we advanced production of Tpoxx to make sure API was available, so we, fortunately, were in a good place when the outbreak hit.
In the future, there isn’t an active order for oral Tpoxx from BARDA but there are two remaining orders from a 2018 contract and several others for intravenous versions of the drug.
Endpoints: So if there isn’t a shortage of treatments right now, why is it still so difficult to get? And why is the government reticent to ship out more?
Gomez: That’s a question for CDC. Distribution is their purview, and there are a lot of complicated regulations because of the SNS, and the fact that it’s approved for smallpox and not monkeypox. We get a lot of questions about use and dosing of the drug, and how to give it to children. For anyone under 13 kilograms [about 29 pounds], the tablet has to be fractionated, which has been done so far for some children, and we’re working on a liquid resuspension dose that hasn’t been used yet.