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Thursday, June 3, 2021

What fuels the 'natural killers' of the immune system

 Despite a name straight from a Tarantino movie, natural killer (NK) cells are your allies when it comes to fighting infections and cancer. If T cells are like a team of specialist doctors in an emergency room, NK cells are the paramedics: They arrive first on the scene and perform damage control until reinforcements arrive.

Part of our innate immune system, which dispatches these first responders, NK cells are primed from birth to recognize and respond to danger. Learning what fuels NK cells is an active area of research in immunology, with important clinical implications.

"There's a lot of interest right now in NK cells as a potential target of immunotherapy," says Joseph Sun, an immunologist in the Sloan Kettering Institute. "The more we can understand what drives these cells, the better we can program them to fight disease."

Despite a name straight from a Tarantino movie, natural killer (NK) cells are your allies when it comes to fighting infections and cancer. If T cells are like a team of specialist doctors in an emergency room, NK cells are the paramedics: They arrive first on the scene and perform damage control until reinforcements arrive.

Part of our innate immune system, which dispatches these first responders, NK cells are primed from birth to recognize and respond to danger. Learning what fuels NK cells is an active area of research in immunology, with important clinical implications.

"There's a lot of interest right now in NK cells as a potential target of immunotherapy," says Joseph Sun, an immunologist in the Sloan Kettering Institute. "The more we can understand what drives these cells, the better we can program them to fight disease."

First in Line

Previous work from researchers at MSK and elsewhere has shown that T cells rely on aerobic glycolysis to carry out their protective functions. But whether NK cells depend on this form of metabolism to power their own activities was not known.

Because Dr. Sun and his colleagues studied NK cells in animals instead of a dish, they could establish what type of metabolism NK cells use and compare it to T cells in a natural setting. They found that NK cells ramp up aerobic glycolysis about five days prior to when T cells respond with their own glycolytic surge.

"This fits with the idea that NK cells are innate immune cells that are really critical for mounting a rapid response," Dr. Sheppard says.

The findings are relevant to ongoing efforts to use NK cells as immunotherapy in people with cancer and other conditions. In particular, they have implications for using NK cells as a form of cell therapy -- when cells are grown outside a patient and then infused back into the patient's blood.

"If you're growing these cells in a dish and you push them to divide too rapidly, they may not have as much potential to undergo aerobic glycolysis when you put them into a patient," Dr. Sheppard says.

The takeaway for researchers designing clinical trials is this: They must find a balance between encouraging NK cells to multiply and preserving their stamina. These NK cells are the paramedics of our immune system, so it's important to keep them speedy and responsive.

The findings were reported June 1, 2021, in the journal Cell Reports.

This research was supported by the Cancer Research Institute, the NCI Cancer Center Support Grant (P30CA08748), Cycle for Survival, the Ludwig Center for Cancer Immunotherapy, the American Cancer Society, the Burroughs Wellcome Fund, and the NIH (grants AI100874, AI130043, AI155558). The study authors declare no conflicts of interest.


Story Source:

Materials provided by Memorial Sloan Kettering Cancer CenterNote: Content may be edited for style and length.


Journal Reference:

  1. Sam Sheppard, Endi K. Santosa, Colleen M. Lau, Sara Violante, Paolo Giovanelli, Hyunu Kim, Justin R. Cross, Ming O. Li, Joseph C. Sun. Lactate dehydrogenase A-dependent aerobic glycolysis promotes natural killer cell anti-viral and anti-tumor functionCell Reports, 2021; 35 (9): 109210 DOI: 10.1016/j.celrep.2021.109210

Transplants Force Patients to Amass Vaccinations to Beat Covid

 

For Jennifer Woda, two doses of the Moderna Inc. vaccine were not enough protection against the Covid-19 virus. Over a month later, she got a third and fourth dose, this time with the Pfizer Inc.-BioNTech SE vaccine.

An opera singer who teaches music to kids, Woda received a kidney transplant in September 2019, one of about 160,000 transplants that have occurred in the U.S. since 2017. Emerging research is now showing that these patients, who suppress their immune system with drugs so their bodies don’t reject donated organs, are dramatically less likely to develop protective antibodies using the authorized vaccine dosage.

That’s spurring some recipients to get extra shots as worries mount over the end of pandemic restrictions and as U.S. vaccine supply outpaces demand. They went to pharmacies and clinics to get their shot on their own without doctor’s notes. Some weren’t asked questions about their vaccination history, and some explained their situation and still got the shot.

“I’m willing to be a guinea pig for my sake, and for everybody’s sake.” Woda said by telephone.

Recent studies by Johns Hopkins University researchers found that just 17% of organ recipients developed detectable antibodies after the first dose of an mRNA vaccine while 54% developed them after a second dose. That compares with 100% in early-stage trials on the vaccines. Even the transplant recipients who did have antibodies had generally lower levels than people with healthy immune systems.

Woda isn’t alone in her actions, though she went a step further than many others. The Johns Hopkins researchers are now following numerous transplant recipients who chose to get a third dose after talking with their doctors. While the research is under review, the findings are encouraging, said Dorry Segev, one of the researchers and a professor of surgery and epidemiology at Johns Hopkins.

Meanwhile, transplant patients are anxiously awaiting more information. While they’re used to taking precautions to avoid getting sick, the fact that the coronavirus is airborne and they now can’t tell which unmasked person is or isn’t vaccinated makes them especially fearful.

“We want to resume our life,” said Janet Handal, a kidney transplant recipient who got a Johnson & Johnson shot more than two months after receiving Moderna’s two-shot regimen. “We want to be able to be out in the world and interact with people as we did before -- travel, go to work, go to dinner, go to the kids’ soccer matches.”

Caution Urged

Segev, though, urges caution. He’s seen a higher rate of so-called breakthrough infections among transplant recipients who have been vaccinated compared with the broader population, as well a higher rate of those patients being hospitalized.

“Now is not the time for immunosuppressed people to celebrate the vaccine,” Segev said in an interview. “Now is the time to get the vaccine and we will learn over the next few months how much they can celebrate.”

Segev said his team is working with the Food and Drug Administration and National Institutes of Health to try to launch a clinical trial studying a third dose for transplant patients. The FDA said it would need data to evaluate a dosing regimen outside the current vaccine authorizations.

The Centers for Disease Control and Prevention said the need for and timing of booster doses have not been established, and the safety and efficacy of a mixed-product series have not been evaluated. As a result. people are not recommended to receive more than one vaccine regimen at this time.

Other Countries

Other countries are further along. A clinical trial studying third doses of the Moderna vaccine for transplant patients has begun in Canada, and French health officials have already recommended that severely immunocompromised people get third doses.

Woda, who lives in Cleveland Heights, Ohio, and has sung extensively in the Northeast Ohio area, said that after she received her kidney transplant she began taking high doses of immunosuppressants to make sure the organ wasn’t rejected.

That meant she had to put her performances and in-person teaching with children on hold to prevent getting sick from other people. Then the pandemic hit and she had to hold back even longer.

“When the vaccines finally came, I was like, ‘yes, yes!’” Woda said. “I’ve been starting to imagine, ‘OK once I get this vaccine, I can probably teach again, and then maybe I can think about auditioning again.’”

But those thoughts abruptly ended after Woda joined the Johns Hopkins study conducted by Segev’s team that looked at the response of transplant recipients to the messenger RNA vaccines. That’s when she learned that her body failed to develop antibodies after two doses of the Moderna vaccine.

She then turned to the Pfizer shot, taking the full two-dose regimen.

‘High Chance’

The Johns Hopkins studies were published in the Journal of the American Medical Association in March and May. The first looked at antibody development after a single dose in more than 400 transplant recipients. The second look at the results after a second dose in more than 600 patients. Other patients also began thinking about what to do next as they learned of their results.

The concept of transplant recipients receiving additional or higher doses is not new, Segev said. In his study, an increase in the share of patients who developed antibodies after the second shot compared with the first “implies to me that there is a high chance we will see a continued increase with three doses.”

Additionally, Segev said, the antibody tests used do not show the entire immune response. The test results are correlated to the amount of neutralizing antibodies that someone develops, but does not show cellular immune responses or how long immunity lasts.

His team is now looking at deeper immunology of people who chose to get a third dose.

Transplant Doctor

Robert Montgomery, a transplant doctor at NYU Langone in New York who received a heart transplant in 2018, was likely one of the earliest transplant recipients to take an additional dose.


After becoming fully vaccinated in January with the Pfizer vaccine, he found he had no antibodies and almost no cellular immune response, he said. He talked with other doctors and weighed his risk of Covid exposure as a health-care worker.

Then, two months after his last Pfizer dose, he decided to take the Johnson & Johnson vaccine, the shot available at the time. His response afterward looked similar to that of someone with a healthy immune system, he said.

He doesn’t currently recommend patients get an additional dose since not enough is known about the safety, he said. But many other transplant recipients heard about his story and took heed.

‘Be Like Bob’

One of those was Handal, who communicated with him as she learned of her response to the Moderna regimen. “I knew what Dr. Montgomery’s response was and what my limited response was so far and I said, ‘I want to be like Bob,’” Handal said in an interview.

Other transplant patients got different combinations of vaccine, and Woda went even further and got four doses.

Stephen Thomas, coordinating principal investigator for Pfizer’s late-stage vaccine trial, said if an immunosuppressed patient is shown not to have an effective response to the vaccine, then it’s reasonable for a health-care provider to discuss the risks and benefits of a booster dose with them, knowing that’s outside the current authorization for the vaccines.

He theoretically doesn’t see a safety concern with people getting a third shot of the original vaccine they took at least several weeks after their initial regimen, but he feels less comfortable with the idea of mixing vaccines as there’s less data on that.

And if someone isn’t responding to a third dose, then it’s unlikely a fourth or fifth shot will be of value and additional shots could expose the patient to risk, he said.

Soon Clear

Segev said it could soon become clear who isn’t likely to respond to a third dose and may need an even more aggressive approach, such as adjusting their immunosuppressants. However, he said, that could be dangerous for transplant patients in particular, since changes in medication risk organ rejection.

Still, transplant patients remain hopeful they’ll see action soon.

Beth Trudeau, an elementary school teacher who got a liver transplant in 1998, said she’s worried about the fall, when she’ll have to return to in-person teaching, and her students likely won’t have access to a vaccine yet.

Her doctors didn’t recommend she take a third dose at this time, so she doesn’t feel comfortable getting one. But she’s known about other patients getting extra doses after talking with their doctors.

“That’s kind of the irritating part of it -- it’s like OK, why is it OK for some and not others?” she said, “Why can’t there be some sort of universal decision on this?"

https://www.bloomberg.com/news/articles/2021-06-01/transplant-patients-bypass-rules-on-shots-in-push-to-beat-covid

Coloradans 12-17 who get vaccine eligible for $50,000 scholarships in new sweepstakes

 The state will enter Coloradans ages 12-17 who have received at least one dose of a coronavirus vaccine into a sweepstakes for a $50,000 college scholarship, Gov. Jared Polis announced Wednesday.

Twenty-five total Colorado kids will win.

There drawings each Monday in June, winners will be chosen and revealed the following Friday. The first drawing will be held June 7 and the last winner will be revealed on July 9. 

“We know that the pandemic had a very significant impact on students and on education. We saw undergraduate enrollment decline over the last year and a half,” Angie Paccione, executive director of the state department of higher education, said at a news conference Wednesday. “Many first-year students decided to take a gap year. And so this is a way, this scholarship sends a clear message to our state that we need you for our Colorado comeback.”

Polis said any person in the 12-17 age group who has been vaccinated in the state will automatically be entered into the eligibility pool.

Winners will have their scholarship money deposited into a 529 CollegeInvest account that will grow over time. The funds can be used for technical programs and credential programs, not just four-year institutions.  

The money can be used to cover tuition at any college, not just in Colorado.

The scholarship drawings come in addition to a $5 million coronavirus vaccine sweepstakes Colorado is offering for people 18 and up who have received at least one dose of coronavirus vaccine. The first drawing for that pool happens Wednesday and the winner will be announced Friday.

The five winners of the adult sweepstakes will get $1 million each.

Funds for both campaigns come from the CARES Act, the federal stimulus passed in March 2020.

Polis said a quarter of 12- to 17-year-olds in Colorado have already been vaccinated with at least one dose of a coronavirus vaccine. The Pfizer vaccine is the only COVID inoculation currently available to that age group in the U.S. 

The sweepstakes are aimed at boosting Colorado’s stagnant vaccination rates and building off the success of Ohio, which was the first state to introduce a similar set of sweepstakes initiatives. Ohio’s vaccination rate increased after its sweepstakes were announced, leading a number of states to follow suit.

“Every winner is an ambassador for the vaccination program,” Polis said, “to demystify it, to highlight it, to show that there’s still many more prizes ahead.”

Polis also introduced the Power the Comeback Business Pledge on Wednesday, an initiative to encourage business leaders to help promote vaccinations. 

Under the pledge, businesses can commit to a number of steps to promote vaccination and COVID-19 safety, including asking unvaccinated people to wear masks indoors, hosting vaccination clinics for employees providing incentives to employees to get vaccinated, and reminding employees to get vaccinated.

“Colorado businesses big and small have been supporting the state’s pandemic response in many ways,” said Pat Meyers, executive director at the Office of Economic Development and Trade, “and they are now powering our economic comeback.”

Meyers added: “The more Coloradans are vaccinated, the more our economy can grow.”

https://coloradosun.com/2021/06/02/colorado-coronavirus-vaccine-scholarships/

Bristol-Myers is sued for $6.4 billion over delayed cancer drug

 Bristol Myers Squibb Co (BMY.N) was sued for $6.4 billion on Thursday for allegedly delaying its Breyanzi cancer drug to avoid payments to shareholders of the former Celgene Corp, which the drugmaker bought in 2019.

According to a complaint in Manhattan federal court, Bristol Myers failed to use contractually required "diligent efforts" to win U.S. Food and Drug Administration approval for the non-Hodgkin lymphoma drug by a Dec. 31, 2020, deadline.

By missing the deadline, Bristol Myers was excused from owing an additional $9 in cash to Celgene shareholders for each share they held, enabling it to acquire Celgene at an "enormous discount" and enjoy a "windfall," the complaint said.

Bristol Myers bought Celgene for $80.3 billion in cash and stock in November 2019. It won FDA approval for Breyanzi, whose chemical name is lisocabtagene maraleucel, on Feb. 5.

The lawsuit was brought by UMB Bank NA, acting as a trustee for Celgene's former shareholders.

"We will not be commenting on pending litigation," Bristol Myers said in a statement.

The $9 per share "milestone" payment had been contingent on New York-based Bristol Myers winning FDA approval by specified deadlines for three drugs that Celgene had been developing.

UMB said Bristol Myers withheld or belatedly submitted critical information to the FDA for Breyanzi's approval, and did not prepare its manufacturing plants for required inspections.

"Other cellular therapies based on similar technology have received FDA approval without the issues and ineptitude that plagued Bristol Myers, and in substantially less time," UMB said.

A lawyer for the Kansas City, Missouri-based bank declined additional comment.

Bristol Myers won FDA approval for the two other Celgene drugs, Zeposia for multiple sclerosis and Abecma to treat multiple myeloma, by the specified deadlines.

The case is UMB Bank NA v Bristol-Myers Squibb Co et al, U.S. District Court, Southern District of New York, No. 21-04897.

https://www.reuters.com/business/healthcare-pharmaceuticals/lawsuit-says-bristol-myers-avoided-64-bln-payment-by-delaying-cancer-drug-2021-06-03/

Pandemic upside: Flu virus became less diverse, simplifying task of making flu shots

 In the eight years leading up to the Covid-19 pandemic, one of the subtypes of influenza A viruses started acting bizarrely. Flu viruses continuously evolve, to evade the immune defenses humans develop to fend them off. But after 2012, H3N2 started to behave differently.

It was almost as if there was a falling out within a family. The viruses formed into factions — clades, in virologists’ language — drifting further and further apart with each passing year and making the process of choosing the version of H3N2 to include in flu shots an increasingly challenging task.

The greater the genetic distance between the clades, the bigger the cost of making the wrong choice. Vaccine that protects reasonably well against one might perform poorly if the other turned out to be the dominant strain in a given winter. In fact, that’s precisely what happened in the 2017-18 season, when the flu shot failed to protect three-quarters of vaccinated people in the U.S. against the H3N2 strain in circulation.

But an unexpected upside of the Covid-19 pandemic may have solved this problem for us — or at least made flu’s diversity more manageable.

With Covid suppression measures like mask wearing, school closures, and travel restrictions driving flu transmission rates to historically low levels around the world, it appears that one of the H3N2 clades may have disappeared — gone extinct. The same phenomenon may also have occurred with one of the two lineages of influenza B viruses, known as B/Yamagata.

Neither has been spotted in over a year. In fact, March of 2020 was the last time viral sequences from B/Yamagata or the H3N2 clade known as 3c3.A were uploaded into the international databases used to monitor flu virus evolution, Trevor Bedford, a computational biologist at the Fred Hutchinson Cancer Research Center in Seattle, told STAT.

If the global pool of flu viruses has truly shrunk to this degree, it would be a welcome outcome, flu experts say, making the twice-a-year selection of viruses to be included in flu vaccines for the Northern and Southern hemispheres much easier work.

“I think it has a decent chance that it’s gone. But the world’s a big place,” Bedford said of the H3N2 clade that may have disappeared.

Florian Krammer, a flu expert at Mount Sinai School of Medicine in Manhattan, has been scouring genetic databases looking for B/Yamagata viruses. He’s hoping the viruses in this lineage are gone for good.

“Just because nobody saw it doesn’t mean it has disappeared completely, right? But it could,” Krammer said.

Flu is complex and a brief primer might be helpful here. There are two key families that cause human disease, influenza A and influenza B. Two subtypes of flu A viruses currently transmit among people, H1N1 and H3N2. Within those two subtypes are subclassifications or clades, with H3N2 viruses having more diversity than H1N1.

Flu B doesn’t have subtypes, but its viruses divide into two “lineages”, B/Victoria and B/Yamagata. In the not-too-distant past only one of the B viruses was included in flu shots every year, but now most brands are quadrivalent — four-in-one shots that include one version each of the H1N1 and H3N2 viruses, and both flu B viruses.

“We work so hard to get quadrivalent vaccines … and now, if really Yamagata has disappeared, then actually trivalent [vaccine] would be okay again,” said Ben Cowling, a flu expert at Hong Kong University. For the record, Cowling is among the skeptics when it comes to the question of whether B/Yamagata is actually gone.

So is Cécile Viboud, a flu epidemiologist at the National Institutes of Health’s Fogerty International Center.

“It’s hard to rule out,” Viboud said, adding these viruses could be circulating at low levels in places that didn’t use the types of non-pharmaceutical interventions like mask wearing and social distancing that other countries have employed to suppress Covid transmission. “The world is a very big place.”

The measures used to slow the spread of Covid-19 have had a dramatic impact on transmission of a number of respiratory viruses. Flu, respiratory syncytial virus — known as RSV — and many of the other bugs that afflict us during cold and flu season have been mercifully absent during the pandemic.

During a typical year, the genetic sequences of about 20,000 flu viruses are logged into GISAID, a repository used by researchers and public health officials to monitor the evolution of influenza and coronaviruses. But in the past year, only 200 were uploaded, Bedford said.

Part of that is likely due to the fact that labs that do viral sequencing are prioritizing work on SARS-CoV-2, the virus that causes Covid. But a big factor here is that there is just a lot less flu transmission occurring, around the globe. That has led to a substantial winnowing of the pool of human flu viruses.

“There had been maybe five-ish, six-ish [H3N2] clades circulating and now there’s two or three that made it through that bottleneck,” Bedford said.

Though there’s been little flu illness globally, there are places that have seen outbreaks during the pandemic, he noted, saying China recorded flu B transmission — the Victoria lineage — and West Africa, Bangladesh, and Cambodia had H3N2 activity.

Richard Webby, director of the World Health Organization Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, cautioned that only a portion of flu viruses ever undergo genetic sequencing, so predictions about which flu viruses may have disappeared that are based on what’s in the databases risk being wrong.

But Webby does believe there has been a large reduction in the diversity of the circulating flu viruses, saying it will be interesting to see how that plays out in coming years.

“Without doubt this is definitely going to change something in terms of the diversity of flu viruses out there. The extent to which it changes and how long it stays changed are the big question marks. But we have never seen this before,” said Webby, whose center is based at St. Jude Children’s Hospital in Memphis.

His bet is that the B/Yamagata viruses aren’t gone, noting the flu B virus lineages sometimes go quiet for a while, only to reappear later.

“But I do think we’re likely to lose a little bit of the H3N2 diversity. That’s a great thing. … Currently when we sit down to make recommendations for vaccine strains, it’s always the headache virus,” Webby said.

“If we have to pick a [subtype] to lose diversity in, that would be the one.”

https://www.statnews.com/2021/06/02/pandemic-upside-flu-virus-became-less-diverse-simplifying-task-of-making-flu-shots/

EU’s COVID jab certificate scheme goes live in seven countries

 The first batch of EU countries have started recognising the vaccination status of travellers using digital vaccine certificates as the bloc moves towards freeing up travel ahead of the summer period.

Germany, Greece, Bulgaria, Czech Republic, Denmark, Croatia and Poland are the first to start using the scheme, which will allow people who have been fully vaccinated against COVID-19, tested negative recently, or recovered from the disease to travel without restriction within the EU.

The document – which is available in digital or paper form – will be “free of charge, secure and accessible to all,” according to the European Commission, and may be scanned at the point of departure or arrival within the EU.

National authorities are in charge of issuing the certificates, which bear a QR code that includes key information including a unique identifier designed to prevent forgery. In the interest of privacy, all data remains on the certificate and isn’t stored or retained when it is scanned in another EU member state.

The commission has set a 1 July deadline for the remaining 20 member states to sign up, after which a phase in period will take place until 12 August.

While not a legal requirement for travel, the aim is for all EU member states to be in a position to accept the certificate by the peak summer holiday season “to help ensure that restrictions currently in place can be lifted in a coordinated manner”.

EU countries are still free to impose their own restrictions on travel, for example if they are concerned about the emergence of new variants.

“The EU Digital COVID Certificate shows the value added of effective e-health solutions for our citizens,” said Stella Kyriakides, the EU commissioner for health and food safety

“EU citizens are looking forward to travelling again, and they want to do so safely,” she added. “Having an EU certificate is a crucial step on the way.”

The UK meanwhile has updated the NHS app (note: not the NHS COVID-19 app used for contact tracing) so that it can be used to prove vaccination status when traveling abroad – but according to media reports has abandoned plans to make certification a requirement of entry to mass events, pubs or shops.

Not all countries will accept the NHS app as proof of vaccination alone however, so people may still have to adhere to other rules when traveling abroad, such as taking a pre-departure test.

https://pharmaphorum.com/news/eus-covid-jab-certificate-scheme-goes-live-in-seven-countries/

Replimune heads for the liver, fails to impress

 Early indications at SITC last year that Replimune’s oncolytic virus approach was working in skin cancer sent the company’s stock up 50%, and further cuts of that data released today point to deepening responses. But the first look at a follow-on CTLA-4-armed project, RP2, combined with Opdivo, seemed to take the shine off the progress.

A further two complete responses were reported with RP1, the company’s lead project, on top of the seven revealed at last October, out of 36 patients treated in the melanoma arm of the Ignyte trial. A very early cut of data on RP2 found 6 partial responses among 27 treated patients, giving an ORR of 22%; it should be remembered that these patients had exhausted all other options.

The company also unveiled plans today to push RP2 and a third project, RP3, into a liver metastasis setting. This was prompted by better than expected responses in a handful of patients whose disease had spread to the organ, persuading the company that the setting was worthy of “aggressive development”, Replimune’s founder and head of research, Rob Coffin, said on an investor call today.

Six patients with liver disease have responded to either RP1 or RP2, three of whom had the oncolytic virus injected into their liver tumour. The remaining three had a liver response despite having a tumour elsewhere injected, supporting the theory that these projects are eliciting a systemic immune response, according to Professor Mark Middleton, head of oncology research at Oxford University and Replimune’s lead investigator.

Of these six patients, two had complete responses, both occurring in cutaneous melanoma, while four partial responses were seen in cutaneous melanoma, uveal melanoma, oesophageal and MSI-high colorectal cancer. Responses were durable, stretching out to almost two years. But no denominators were revealed, so it is unclear whether non-responders with liver metastases have been seen. 

Pushing on

In the coming months Replimune plans to expand enrolment into an ongoing trial of RP2 to include patients with liver metastases of defined tumour types, including GI, lung and breast cancers. Further data in uveal melanoma is of particular interest – should the signal be confirmed here the company plans to move to “registration-directed development”.

For RP3, early clinical work testing its safety when injected straight into the liver will commence, followed by a monotherapy and PD-1 combination trial.

The liver is the most common site of tumour spread, and the presence of liver metastases renders the disease resistant to immunotherapy. According to Replimune this is due to liver-resident macrophages, which ultimately dampen T-cell activation. The company maintains that its oncolytic virus projects can counter this resistance, by boosting T-cell production and reducing apoptosis.

This remains to be proven, of course, and for now Replimune’s main focus is RP1 and RP2 in skin cancer. The first data on RP2 plus Opdivo were also revealed today, and Professor Middleton stressed that this was a very early cut of the data and that the project’s true effectiveness remained hard to assess.

Replimune's data with RP2 + Opdivo
 All tumoursCutaneous melanomaUveal melanomaSarcoma
Number of patients27964
Ongoing PR64*10
Best response SD9322
On study with opportunity for response8232
Current ORR22%44%17%0%
*Two unconfirmed. Source: company presentation.

A 12% dip in Replimune’s share price morning suggests that investors were expecting something more. It is important to remember that this is essentially a salvage setting, and many of the patients had failed anti-PD-1 therapy. The trial is continuing.

A later cut of the ongoing trial of RP1, Ignyte, was perhaps more impressive, with more patients converting to complete responses and durability in some cases approaching two years.

Still, the relatively complex administration of oncolytic viruses has been a major drawback, and is thought likely to restrict their application to easy-to-reach tumours and possibly salvage settings. Indeed, Mr Coffin had founded Biovex, sold to Amgen in 2011, whose oncolytic virus Imlygic has largely remained a niche treatment.

For the negative view to change Replimune needs these data to keep improving, and confirm these very early signals in liver settings.

Melanoma cohort of Ignyte trial - RP1 + Opdivo