CMV infection in HSCT recipients; Current trends and perspectives Prof CMV infection in HSCT recipients; Current trends and perspectives Prof. Per Ljungman Center for Allogeneic Stem Cell Transplantation Karolinska University Hospital and Karolinska Institutet Stockholm, Sweden

Disclosures Advisory boards: AiCuris; Merck, Oxford Immunotech Investigator: Merck, Astellas, Oxford Immunotech DSMB/DRC: Shire

Timing of management options Viral load Viral disease Time Diagnosis of viral infection Treatment of established disease Pre-emptive therapy Prophylaxis

Treat established CMV disease A failure of strategy Associated with significant mortality in the most severely immunosuppressed patients

What is the risk for CMV disease today? Placeboarms in prospective randomized studies Author Journal Year N Incidence Marty et al Lancet ID 2011 227 2.4% N Engl J Med 2013 59 3.0% Chemaly et al 2014 33 0% 2017 170 1.8%

Patients in and outside of clinical trials

Real life probability of CMV disease Green et al: Lancet Haematol 2016

CMV Following Hematopoietic Cell Transplantation Current Strategies Infection Universal prophylaxis ‘Risk-adapted’ prophylaxis Pre-emptive Therapy To prevent CMV infection/reactivation To prevent CMV infection/reactivation in high-risk subgroups (A)symptomatic CMV infection detected by a screening assay CMV disease Disease J.Maertens 2018

The fight! Preemptive therapy Prophylaxis

CMV replication is associated with mortality! Retrospective analysis of seropositive patients monitored by qPCR. Effect of detection of any level of viremia Multivariate Cox model Day 0 – 60 Day 61 – 365 All cause mortality 2.6 (1.4 – 5.0) 1.7 (1.2 – 2.4) Non-relapse mortality 1.3 (0.9 – 2.0) 1.8 (1.2 – 2.6) Green et al Lancet Haematol 2016

Prophylaxis – previous studies Aciclovir/valaciclovir are not effective enough Ganciclovir and foscarnet are effective but toxic in HSCT Valganciclovir effective in SOT Resistance / intolerance remains as problems Immune globulin is not effective in HSCT Failure of phase III studies for maribavir, brincidofovir, and CMV DNA vaccine

Letermovir (AIC246) - Belongs to a new class of compounds (a 3,4-dihydro-quinazoline-4-yl-acetic acid derivative) Inhibits CMV through a novel mechanism involving the viral terminase complex Potent CMV activity in vitro & in vivo No effect on other herpesviruses No cross-resistance with drugs currently used in treatment of CMV

Clinical Significant CMV Infection (%) Time to Clinically Significant CMV Infection Primary Efficacy Population; Patients without Detectable CMV DNA at Randomization 60 50 40 30 20 10 Letermovir vs. Placebo Stratified log-rank test, Two-sided p=0.0005 Placebo Clinical Significant CMV Infection (%) Cumulative Rate of Letermovir 2 6 10 14 18 24 Post-Transplant Week Letermovir 325 320 299 279 270 254 212 Placebo 170 169 135 96 85 77 70 Subjects at risk

Clinical Significant CMV Infection (%) Time to Clinically Significant CMV Infection Primary Efficacy Population; Patients without Detectable CMV DNA at Randomization High Risk Stratum Low Risk Stratum 60 50 40 30 20 10 Log-rank two-sided p<0.0001 60 50 40 30 20 10 Log-rank two-sided p<0.0001 Placebo Placebo Clinical Significant CMV Infection (%) Cumulative Rate of Letermovir Letermovir 2 4 10 12 14 16 18 20 22 24 6 8 2 4 10 12 14 16 18 20 22 24 6 8 Post-Transplant Week

All-cause mortality through w.24 Letermovir Placebo Patients with CS-CMVi 17.7% 29.5% Patients without CS-CMVi 19.7% 18.3% Letermovir neutralizes the negative effect of significant CMV replication

Real life experience Implemented at some centers at all seropositive patients. Some centers have been using it in ”high risk” patients only Some resistance is developing. Break-throughs with disease have been seen Secondary prophylaxis have also been used (off label)

Prophylaxis in allogeneic HCT; Antiviral drugs ECIL 2017 Grading References Comment Aciclovir CI Prentice, Lancet 1994 Milano, Blood 2011 Less efficient than valaciclovir Valaciclovir BI Ljungman, Blood 2002 Winston CID 2003 Association with preemptive strategy Ganciclovir/ Valganciclovir CIIh Winston, Ann Intern Med 1993 Goodrich , Ann Intern Med 1993 Montesinos, BBMT 2009 Cord blood SCT Foscarnet DIIu Ordemann, Ann hematol 2000 Bregante et al, Bone Marrow Transplant 2000 Letermovir AI Marty et al, NEJM 2017 . Ljungman et al; Lancet Infect Dis; in press 2019

How far have we come? So, early intervention should be the goal

What is the rationale for monitoring and preemptive treatment A sensitive diagnostic test is available CORRECT – Many studies A positive result is predictive for development of disease Partly CORRECT – Not for all types of disease Early intervention can prevent disease CORRECT An effective (and safe) antiviral drug is available YES AND NO

Testing issues All PCRs are not created equal!! Starting materials DNA extraction methods Primer/probe selection Variability International standard!!

The variability in CMV DNA results reported on individual samples samples have been reduced by the international standard, but ongoing clinically relevant variability persists, preventing meaningful interassay result comparison CID 2017

CMV viral load cut-off values There is major variability between patients There is still variability between assays It is therefore not possible (or meaningful) to give a standard cut-off reocmmendation to be used at different centers (outside clinical trials)

First line preemptive therapy – ECIL 2017 The only data available for preemptive therapy of asymptomatic patients exists in allogeneic HSCT recipients. Preemptive antiviral therapy based on detection of CMV nucleic acid (or antigen) is effective for prevention of CMV disease (AI) Either iv ganciclovir or foscarnet can be used for first line preemptive therapy (AI) Valganciclovir can be used in place of iv ganciclovir or foscarnet (except in patients with severe GI GVHD); AIIu) The combination foscarnet+ ganciclovir is not recommended (DIII) The choice of drug depends on time after HSCT, risk of toxicity, and previous antiviral drug exposure Ljungman et al; Lancet Infect Dis; in press 2019

Repeated CMV reactivations Common in high risk patients Frequently poor activity/tolerability of existing antiviral drugs Associated with poor T-cell control of CMV Increased risk for resistant strains

Second and third line preemptive therapy The alternate drug of ganciclovir/valganciclovir or foscarnet can be considered for second line pre-emptive therapy (AIIu) Cidofovir can be considered for second/third line pre-emptive therapy (3-5 mg/kg/week) but careful monitoring of the renal function is required (BIIu). The combination of ganciclovir and foscarnet might be considered for second/third line pre-emptive therapy (CIIu) Reduce immunosuppression if possible (BIII) No recommendation can be given for the antiviral drugs in development Leflunomide or artesunate can be considered in patients resistant/refractory to available antiviral drugs (CIII) Addition of iv immune globulin for preemptive therapy is not recommended (DIII) EXPAND THIS DISCUSSION ALSO TO TREATMENT OF DISEASE Ljungman et al; Lancet Infect Dis; in press 2019

How common is antiviral resistance in HSC recipients? Varies between patient populations Ganciclovir resistance 0% in a prospective randomized study (Boeckh et al Ann Intern Med 2015) 0% in auto and allo SCT non-haplo recipients in a large prospective cohort study 9.6% in haploidentical allo SCT recipients (Shmueli et al JID 2013

CMV genes and antiviral drugs

Most “resistance” is clinical!

Causes for “clinical” resistance If you give oral therapy, does the patient take the drug? Vomiting? Does the patient absorb the oral drug? What are the drug levels? TDM for ganciclovir Viral replication kinetics Poor T-cell function

Response to antiviral therapy takes some time! Mattes et al JID 2005

When to Suspect Drug Resistance High risk clinical setting (severe T-cell immunodeficiency) Prolonged drug exposure (usually > 6 weeks) Rising viral load or persistent culture positive >2 weeks after full dose therapy (GCV/VGV) Progressive disease after prolonged therapy

Treatment of resistant/refractory patients Increase dose of ganciclovir/TDM Foscarnet Cidofovir Maribavir Letermovir/ Brincidofovir T-cells Leflunomide Artesunate

Foscarnet/cidofovir Standard second line therapies Most ganciclovir resistant patients can be managed Multidrug resistance is rare However, toxicity problems are common (renal toxicity, electrolyte disturbances, cystitis)

Maribavir Sucessful phase II study for prophylaxis Failed phase III studies for prophylaxis Case series on refractory patients. Phase II study of refractory patients finalized. Phase III studies ongoing

Maribavir for Treatment of CMV Resistant or Refractory to Ganciclovir or Foscarnet: A Phase 2 Trial MBV 400 mg twice daily Weeks 1-3 Weeks 3-6 Weeks 6-24 MBV 1200 mg twice daily MBV doses blinded Randomization • HCT or SOT recipient • R/R CMV • ≥1,000 CMV DNA copies/mL At week 3 and week 6 visits, minimum virologic responses are required for study drug treatment to continue PCR CMV testing Day 1, weekly to week 6 Study evaluations/PCR CMV testing Every 2 weeks to week 12; weeks 16, 20, and 24 Week 4 Week 8 Week 12 MBV 800 mg twice daily Screening Study drug administration (maximum 24 weeks) Follow-up (post-treatment weeks 1-12) Week 1 a Did not achieve ≥1 log reduction in CMV DNA with ≥14 d of previous treatment; ≥1,000 CMV DNA copies/mL at screening. b Resistance mutations in UL97 and/or UL54; meets refractory criteria. c Requirements to continue treatment: past week 3, any decline in CMV DNA at week 2; past week 6, ≥2 log reduction or undetectable CMV DNA at week 5. Papanicolaou G, et al. BMT Tandem 2017. Abstract 45. ClinicalTrials.gov identifier: NCT01611974. G. Papanicolaou 2018

Time to Undetectable Plasma CMV DNA was Similar Across all Maribavir Doses Median estimated time to confirmed undetectable plasma CMV DNA at any time (days [95% CI]) were similar: 24 (15, 31), 28 (15, 38), 22 (19, 30), and 23 (21, 29) for MBV 400 mg, 800 mg, 1,200 mg (twice daily), and MBV all doses, respectively Papanicolaou G, et al. BMT Tandem 2017. Abstract 45. ClinicalTrials.gov identifier: NCT01611974. G. Papanicolaou 2018

Letermovir No data in children Likely to be tested in refractory/resistant situations (off label) Dose not determined. Very limited published data Resistance found in vitro and in vivo. Unclear clinical relevance as of today

Adoptive T-cell therapy In develpment for 30 years Major advances in technology have been achieved over time Most (almost all) data are from phase I – II type studies In practice, it is still far away from routine therapy/ available for most centers

Effect of CTL Uhlin et al CID 2012

Response, % (n/N) CMV EBV AdV BKV HHV-6 CR + PR 94 (16/17) 100 (2/2) 71 (5/7) 93 (14/15) 100 (2/2)‡ CR 65 (11/17) 33 (5/15) 0 (0/2)‡ Single-arm phase II study in which post-HSCT pts infected with refractory* CMV, EBV, AdV, BKV, and/or HHV-6 were treated with closely HLA-matched, third-party, multivirus-specific donor CTLs from investigative site bank (N = 38) Pts received 2 x 107 CTLs/m2; partial responders could receive additional infusions every 2 wks Efficacy: overall, CR or PR† achieved for 91% of viral infections; all pts infected with 2 viruses (n = 6) achieved CR or PR for both viruses Intolerance to or 14-day failure of standard antiviral treatment. †CR: return of viral load to normal and clinical signs/symptoms resolution; PR: viral load decrease of ≥ 50% and/or improvement of clinical signs/symptoms. ‡n = 1 additional pt not evaluable. Small single-center studies have shown feasibility and effectiveness CMV or multivirus specificities No major safety concerns Randomized trials are needed Safety: grade 1 skin GVHD, n = 1 (resolved); chronic skin GVHD flare, n = 3 (immunosuppression discontinued); transient fever, n = 2 Tzannou I, et al. J Clin Oncol. 2017;35(31):3547-3557.

How do I treat very difficult CMV problems? The numbers game In real life, this is quite rare 1-2 patients/year at my center Individual management based on transplant history, GVHD, tolerability of drugs, possibility to use immune therapy.

One size doesn’t fit all

A look into the situation in 2022 Or………………

Since transplanters are innovative "The person who takes medicine must recover twice, once from the disease and once from the medicine." - William Osler, M.D.