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Announcement on phase 1 leprosy vaccine trial suffers from hyperbole, lack of evidence

Promising New Leprosy Vaccine Moves Into Human Trials

Our Review Summary

The news release focuses on a recently launched phase 1 clinical trial, designed to test whether a potential leprosy vaccine called LepVax is safe enough to move forward into more advanced clinical trials. The release does not address cost, prematurely refers to the vaccine as “a breakthrough,” and does little to discuss potential harms — other than to note that phase I trials are focused on safety. The release also offers little information about the effectiveness of previous attempts to develop leprosy vaccines, which would have been valuable context.

The release is clear about the potential availability of the vaccine, noting that the phase 1 trial could be completed in 2018 and that a decision to proceed with more trials will be made then.


Why This Matters

The release states, in its very first sentence, that launching this phase 1 clinical trial “marks a significant step forward in the prevention and treatment of leprosy.” That’s a bold statement, and strong claims require strong evidence. The fact is that, according to, 25 percent of treatments in phase 1 trials don’t even make it to a phase 2 trial. And, according to a 2016 report from the biotech group BIO, less than 10 percent of treatments that enter phase 1 trials are eventually approved for clinical use (though the success rate rises to 11.9 percent for non-cancer drugs). The problem of overstating the accomplishment of reaching phase 1 trials is compounded by the fact that, while the release mentions previous attempts to vaccinate against leprosy, the release doesn’t mention how effective other leprosy vaccines were (or are). Entering clinical trials is only one milestone on the path to clinical use. What’s more important is how the proposed treatment performs while in those trials. The release does make this clear, much lower in the text, but it would have been stronger if it had dialed back the bold claims from the beginning.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Costs aren’t mentioned. We know that it is far too soon to put a specific price tag on the treatment, but the release could have discussed the feasibility of scaling up manufacturing, whether the process is costly or time-consuming, etc. How much could the vaccine, which the release tells us is the first “developed specifically for leprosy” and “produced by totally synthetic methods,” cost patients? Based on the information in the release, it’s anyone’s guess.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?


The release does note that the study will be focused on safety and immune system response which earns a minimal Satisfactory rating for clearly establishing the purpose of a phase 1 study.

There is currently no information on how effective this vaccine is in human subjects. There is also no mention of how this vaccine weakens the mycobacterial load in those already exposed.

Does the news release adequately explain/quantify the harms of the intervention?


The whole goal of a phase 1 trial is to determine what, if any, potential harms are associated with a given treatment. The release makes note of this, which is why we give it a satisfactory rating. That said, if animal trials turned up any potential harms that may be relevant to human subjects, those should have been mentioned here. And even if animal trials didn’t turn up any potential harms, the release would have been stronger if it had mentioned that.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release makes multiple claims that can’t be supported by a phase 1 study. This release is focused on the beginning of a phase 1 trial, so there’s no evidence to review yet, and yet a researcher is quoted saying, “We believe this may be the most exciting breakthrough in leprosy treatment since multi-drug therapy, the current treatment for leprosy, was launched in the 1980s. We look forward to this vaccine improving the health outcomes of people diagnosed with leprosy. And, it may be that this vaccine can lead to interruption of the transmission of leprosy all together.” Those statements can’t be supported for an experimental vaccine that has never even been tested in a human.

Does the news release commit disease-mongering?


No disease mongering here.

Does the news release identify funding sources & disclose conflicts of interest?


Funding sources are all clearly laid out.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The release states that there are no other leprosy vaccine candidates, despite the fact that multiple countries (including India and Brazil) already use a leprosy vaccine (though the effectiveness of that vaccine is widely debated). The release would have been stronger if it had noted this vaccine and articulated how LepVax aims to improve on it.

The release notes that drug therapies do exist for leprosy, though it focuses on the drawbacks associated with treatment rather than the extent to which the treatment is effective. The release also refers to “previous attempts” — presumably at developing a vaccine — “that have used vaccines primarily developed for other diseases.” But it doesn’t discuss how effective these “previous attempts” have been. For example, a 1996 paper in The Lancet reported that a modified vaccination regime involving the so-called BCG vaccine, which is also used to vaccinate against tuberculosis, gave at least 50 percent protection against leprosy.

Presumably the goal of LepVax is to improve the efficacy of leprosy vaccination, but the release would have been stronger if it had addressed this and provided the relevant context. Again, the idea that it increased humoral and cellular responses to those already exposed requires further explanation (this was noted in the description on clinical

Does the news release establish the availability of the treatment/test/product/procedure?


The release does a good job here, noting: “Early results from the Phase I study should be available in 2018, and the partners are currently exploring mechanisms to advance the vaccine through later-phase clinical trials should results from the Phase I study (clinical trial NCT03302897) support further evaluation.”

Does the news release establish the true novelty of the approach?


This is a mixed bag. The release does try to articulate how this vaccine differs from previous attempts to develop leprosy vaccines. For example, the release states that previous vaccination efforts have relied on vaccines developed for preventing other diseases. However, that may be misleading. For example, as this 2011 paper describing the history of leprosy vaccine research notes, one long-running (and large-scale) trial in the 1980s and 1990s involved modifying an existing vaccine with “irradiated, autoclaved M. leprae purified from the tissues of infected armadillos” (M. leprae being the bacteria that cause leprosy). That sounds like something targeting leprosy pretty specifically.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

The release is unsatisfactory here on multiple fronts. First, a researcher is quoted calling the   phase 1 study a “breakthrough” which it clearly isn’t.

Second, the release states that, because of LepVax, “it could be possible to prevent disease development in people already infected with the leprosy bacterium.” It could just as easily have said, “it may not be possible to prevent disease development.”

Thirdly, if one is going to make bold claims, where is the evidence to back it up? The only reference we could find to the role of LepVax in limiting the development of leprosy was in a 2014 report from a Novartis Foundation meeting, which referred to a study that was done in an animal model involving 21 armadillos. Both of those concerns, in conjunction with our concerns about calling the beginning of a phase 1 trial a “significant step forward” in leprosy prevention/treatment, give this release a Not Satisfactory rating.

Total Score: 6 of 10 Satisfactory


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