AiCuris’ Pritelivir has now secured FDA endorsement in the form of a Fast Track Designation in immuno-compromised patients.

Based in Wuppertal, Germany, and spun out from Bayer, AiCuris is focused on curing infectious diseases. Its lead candidate for herpes simplex viruses 1 and 2 (HSV-1 and -2), pritelivir, has been watched closely for its promise to eliminate the cold sores that plague up to 3.7B people worldwide at some point in their lives as well as the pesky STI. Now, the FDA has Fast Tracked the drug for patients with weakened immune systems.

These patients are more likely to see flare-ups, and as there is currently no drug available that acts as a herpes cure, an antiviral HIV treatment is the usual way to suppress these recurrences. This overlap isn’t surprising, as HIV and herpes are closely related, frequently appear together, and often worsen each other. Further, if pritelivir succeeds, it could be a stepping stone to a treatment for HIV, perhaps even an HIV cure.


Given the synergy between the two diseases, herpes treatment tolerable by HIV patients would be a welcome development. Current treatments including acyclovir and valacyclovir are based on nucleoside analogs to block DNA synthesis, but pritelivir targets the helicase-primase complex and terminates DNA elongation prematurely. Additionally, pritelivir can protect uninfected cells as it doesn’t require activation with an infected cell.

Last fall, pritelivir cleared Phase I, and in January, preliminary Phase II results showed that it outperforms valacyclovir with respect to virus shedding, genital lesions, and pain. They also hinted at the promise for immuno-compromised patients, and CEO Holger Zimmerman commented that indeed AiCuris would explore this avenue.

AiCuris doesn’t have any direct competitors in the European arena for herpes treatments, let alone a cure, though Genocea across the Atlantic is pursuing genital herpes with an experimental immunotherapy, which just cleared Phase IIb. Even so, the German biotech hasn’t put all of its eggs in this one basket: it’s also developing drug candidates for hepatitis B, antibiotic resistance and cytomegalovirus (CMV), which it licensed to MSD in a record €442.5M deal.

Images via RAJ CREATIONZS, Kateryna Kon /

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  • maku520

    This medicine is not meant to cure patients. Rather, it is a new antiviral medication that disrupts the virus’ ability to replicate in the body. Other drugs on the market (acyclovir, valacyclovir, and famciclovir) also perform this task, but the hope is that pritelivir will do so better
    I am not familiar with laws in the EU, but in the US using the word “cure” for a drug product that has not been identified by the FDA as a cure for marketing purposes is illegal. I would think that the EU would have a similar law. You may want to change the title and content of this article to remove any reference to a cure, especially since this drug is not even meant to be one.


      Thanks for weighing in. First, it should be pointed out that we’re not a marketing outfit. But I do imagine that the EU has similar laws — in which case, you might understand why it’s safest for the company not to call it one. (It might also be worth noting that the company’s slogan is “Anti-Infective Cures.”) The meaning of “cure” is open to philosophical interpretation, and we believe that eliminating symptoms counts.

      • disqus_SmDWRUUWqO

        “The meaning of “cure” is open to philosophical interpretation, and we believe that eliminating symptoms counts” Yeah not really… It implies an end. If you have been cured you would not need further treatment. Your are clearly not talking about a cure but a treatment. Now a treatment can even be 100% effective at treating the symptoms but if you remove the treatment and the symptoms return you have clearly not been cured. This is language not philosophy… That is why we have different words to describe different things…

        • Could you please explain this a little more. If the organism stops replicating, what happens after that? I know viruses are not “alive” but does the genetic material inside the virus stay functional inside the body forever? Would the virus just keep attempting (unsuccessfully) to replicate? I thought that each attempted replication “lost” a little bit of RNA so that if a patient consistently took a medication that prevented replication and the virus kept attempting to replicate anyway – eventually the RNA would be so corrupted as to render the virus ineffective even without the presence of the pharma inhibitor.


            Hi Adreana, we’re not the best resource for your questions — we’d suggest referring to the sources where you found that information or to PubMed for current research on the topic.

  • Pete

    When will this drug be offered to the masses? Do you have a timeline?

  • surethom

    Finally an new antivirals the first one in almost 20 ish years? Wonder when this will get UK NICE approval.?


    Herpes cure is on the way. if it can come true, people with herpes will feel nothing to have it. – MPWH community

  • Sb

    When is it available