LB-9. Durable Efficacy and Continued Safety of Ibalizumab in Treatment-Experienced Patients
Session: Poster Abstract Session: Late Breaker Posters
Saturday, October 22, 2011
Room: Poster Hall B1
Handouts
  • LB-9_BrianBell(2).pdf (407.0 kB)
  • Background: 

    TMB-202, a 24-week (wk) phase 2b double-blinded clinical trial, randomized 113 treatment-experienced HIV+ patients to receive ibalizumab, a monoclonal antibody HIV entry inhibitor, at doses of 800mg IV every two weeks (q2wks) or 2000mg IV every four weeks (q4wks) combined with an optimized background regimen.

    Method: 

    Patients who completed TMB-202 with ≥0.7 log10 viral load reduction from baseline were eligible to receive open-label ibalizumab via investigator-sponsored IND (PI-IND).  Eighty of 109 patients at participating sites were eligible for PI-IND and 55 patients enrolled. All PI-IND patients were assessed for safety and antiviral response. 

    Result: 

    TABLE 1 summarizes disposition of PI-IND patients through May 2011.  Thirty patients received 800mg dosage and 26 received 2000mg dosage.  Fifteen patients discontinued treatment while on PI-IND and 41 continue receiving ibalizumab.

    TABLE 1.  PI-IND Patient Disposition

    Patient descriptor

    800mg q2wk

    2000mg q4wk

    Total N (%)

    Enrolled in TMB-202 at PI-IND participating sites

    58

    51

    109 (100)

    Eligible to continue ibalizumab under PI-IND

    45

    35

    80 (73)

    Eligible but not continuing (patient/physician decision)

    15

    10

    25 (23)

    Eligible and  enrolled under PI-IND

    30

    26*

    56 (51)

    Enrolled and discontinued from PI-IND

    10

    5*

    15 (14)

    On PI-IND thru May 2011

    20

    21

    41 (38)

    *Includes one ineligible patient treated briefly on PI-IND

    No PI-IND discontinuations were due to safety-related reasons.  Seven of 15 discontinuations were due to loss of response (<0.7 Log10 reduction from TMB-202 Baseline viral load) while 6 patients (all from the 800mg arm) had undetectable HIV RNA when discontinued.  The virologic and immunologic status of continuing PI-IND patients are summarized in Table 2.

    TABLE 2.  PI-IND Patient status - last observation

    Endpoint

    800mg q2w (N=30)

    2000mg q4w (N=26)

    Median duration, days

    371

    469

    <400 copies/mL, n (%)

    21 (72)

    19 (73)

    <50 copies/mL, n (%)

    17 (59)

    8 (31)

    >1.0 log10 change from BL , n (%)

    25 (86)

    20 (80)

    Mean change from BL, Log10 copies/mL

    -2.4

    -2.3

    Mean CD4+ T-Cell change from BL, cells/mL

    +95

    +91

    Conclusion: 

    Extended time on ibalizumab has not resulted in any safety-related discontinuations or drug-related SAEs. These data also demonstrate the durability of virologic and immunologic responses.


    Subject Category: H. HIV/AIDS and other retroviruses

    Homayoon Khanlou, MD1, Jerome Devente, MD2, Jeffrey Fessel, MD3, Shannon Schrader, MD4, William Towner, MD5, Steven Weinheimer, PhD6 and Stanley Lewis, MD6, (1)AIDS Health Care Foundation Research, Los Angeles, CA, (2)Living Hope Clinical Foundation, Long Beach, CA, (3)Kaiser Permanente Medical Center, San Francisco, CA, (4)Research Access Network, Houston, TX, (5)Infectious Disease, Kaiser Permanente Medical Center, Los Angeles, CA, (6)TaiMed Biologics USA, Irvine, CA

    Disclosures:

    H. Khanlou, None

    J. Devente, None

    J. Fessel, None

    S. Schrader, None

    W. Towner, None

    S. Weinheimer, TaiMed Biologics: Employee, Salary

    S. Lewis, TaiMed Biologics: Employee and Shareholder, Salary

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