Phase I study of VSV-GP (BI 1831169) as monotherapy or combined with ezabenlimab in advanced and refractory solid tumors.

Patients with advanced, recurrent or metastatic cancer have poor prognosis despite treatment advancements. Vesicular stomatitis virus (VSV)-glycoprotein (GP; BI 1831169) is a chimeric VSV with its neurotropic glycoprotein G replaced by the non-neurotropic GP of the lymphocytic choriomeningitis virus. This live, recombinant oncolytic virus has demonstrated preclinical efficacy as a viral-based immunotherapy due to its interferon-dependent tumor specificity, potent oncolysis and stimulation of antitumor immune activity. Co-administration of the immune checkpoint inhibitor, ezabenlimab (BI 754091), alongside VSV-GP may synergistically enhance antitumor immune activity. Here, we describe the rationale and design of the first-in-human, phase I, dose-escalation study of VSV-GP alone and in combination with the immune checkpoint inhibitor ezabenlimab in patients with advanced, metastatic or relapsed and refractory solid tumors (NCT05155332).

There is a need to develop new treatments for people living with cancer. Immunotherapy is a type of medicine that works by helping the body's natural defenses, known as the immune system, to destroy cancer cells. There are different types of immunotherapies such as oncolytic viruses (OVs) and immune checkpoint inhibitors (ICIs). OVs are viruses that may help destroy cancer cells while leaving normal cells unharmed. They work by replicating within cancer cells; this causes them to burst and release more of the virus which then infects nearby cancer cells and activates the body's immune system. ICIs may be able to work together with OVs to amplify this effect. Vesicular stomatitis virus (VSV)-glycoprotein (GP) is a type of OV that has been shown to effectively destroy cancer cells in animal studies. This first-in-human study will investigate VSV-GP on its own and in combination with an ICI called ezabenlimab for the treatment of late-stage cancer or cancer that has spread to multiple parts of the body. Here, we describe the background and design of this study in progress which aims to find out if VSV-GP alone or in combination with ezabenlimab is effective against cancer, the suitable dose and if any side effects occur. Trial Registration Number: NCT05155332 (ClinicalTrials.gov).

A phase Ib, open label, dose escalation trial of the anti-CD37 monoclonal antibody, BI 836826, in combination with ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia.

BI 836826 is a chimeric immunoglobulin G1 antibody targeting CD37, a transmembrane protein expressed on normal and malignant B cells. This open-label, phase Ib, dose-escalation study was conducted to determine the recommended phase II dose (RP2D) of BI 836826 + ibrutinib in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Eligible patients received 420 mg/day of ibrutinib with escalating doses of BI 836826. BI 836826 was administered in 4-week cycles. After Cycle 12, patients achieving complete response (CR), CR with incomplete marrow recovery, or minimal residual disease-negative partial response could continue to receive BI 836826 + ibrutinib every 4 weeks for ≤ 12 additional cycles. Patients received either 100 mg (n = 3) or 200 mg (n = 3) BI 836826 + ibrutinib. In the 100 mg BI 836826 cohort, one patient received two cycles and two patients received 22 cycles of BI 836826. In the 200 mg BI 836826 cohort, patients received 12, 16 and 20 cycles of BI 836826, respectively. All patients discontinued BI 836826 and continued ibrutinib outside the trial. No dose-limiting toxicities were reported in the maximum tolerated dose (MTD) evaluation period. As the trial was discontinued before the MTD was reached, the RP2D was not determined. Grade 3/4 adverse events (AEs) were predominantly hematological. Pseudomonal bacteremia was the only drug-related AE of special interest. BI 836826 + ibrutinib did not exceed the MTD at doses up to 200 mg in patients with CLL. However, RP2D and MTD were not formally established, as the sponsor discontinued the trial.

A phase Ib, open-label, dose-escalation trial of the anti-CD37 monoclonal antibody, BI 836826, in combination with gemcitabine and oxaliplatin in patients with relapsed/refractory diffuse large B-cell lymphoma.

Background BI 836826 is a chimeric mouse-human monoclonal antibody directed against human CD37, a transmembrane protein expressed on mature B lymphocytes. This open-label, phase I dose-escalation trial (NCT02624492) was conducted to determine the maximum tolerated dose (MTD), safety/tolerability, and preliminary efficacy of BI 836826 in combination with gemcitabine and oxaliplatin in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Methods Eligible patients received intravenous infusions of BI 836826 on day 8 and gemcitabine 1000 mg/m2 plus oxaliplatin 100 mg/m2 on day 1, for up to six 14-day treatment cycles. Dose escalation followed the standard 3 + 3 design. Results Of 21 treated patients, 17 had relapsed/refractory DLBCL and four had follicular lymphoma transformed to DLBCL. BI 836826 dosing started at 25 mg and proceeded through 50 mg and 100 mg. Two dose-limiting toxicities (DLTs) occurred during cycle 1, both grade 4 thrombocytopenia lasting > 7 days, affecting 1/6 evaluable patients (17%) in both the 50 mg and 100 mg cohorts. Due to early termination of the study, the MTD was not determined. The most common adverse events related to BI 836826 treatment were neutropenia (52%), thrombocytopenia (48%), and anemia (48%). Eight patients (38%) experienced BI 836826-related infusion-related reactions (two grade 3). Overall objective response rate was 38%, including two patients (10%) with complete remission and six patients (29%) with partial remission. Conclusions BI 836826 in combination with GemOx was generally well tolerated but did not exceed the MTD at doses up to 100 mg given every 14 days.

Phase I dose escalation study of BI 836826 (CD37 antibody) in patients with relapsed or refractory B-cell non-Hodgkin lymphoma.

BI 836826 is a chimeric immunoglobulin G1 antibody targeting CD37, a tetraspanin transmembrane protein predominantly expressed on normal and malignant B cells. This phase I, open-label study used a modified 3 + 3 design to evaluate the safety, maximum tolerated dose (MTD), pharmacokinetics, and preliminary activity of BI 836826 in patients with relapsed/refractory B cell non-Hodgkin lymphoma (NHL; NCT01403948). Eligible patients received up to three courses comprising an intravenous infusion (starting dose: 1 mg) once weekly for 4 weeks followed by an observation period of 27 (Course 1, 2) or 55 days (Course 3). Patients had to demonstrate clinical benefit before commencing treatment beyond course 2. Forty-eight patients were treated. In the dose escalation phase (1-200 mg) involving 37 Caucasian patients, the MTD was 100 mg. Dose-limiting toxicities occurred in four patients during the MTD evaluation period, and included stomatitis, febrile neutropenia, hypocalcemia, hypokalemia, and hypophosphatemia. The most common adverse events were neutropenia (57%), leukopenia (57%), and thrombocytopenia (41%), and were commonly of grade 3 or 4. Overall, 18 (38%) patients experienced infusion-related reactions, which were mostly grade 1 or 2. Preliminary evidence of anti-tumor activity was seen; three patients responded to treatment, including one complete remission in a Korean patient with diffuse large B cell lymphoma. BI 836826 plasma exposure increased more than proportionally with increasing doses. BI 836826 demonstrated preliminary activity; the most frequent adverse events were hematotoxicity and infusion-related reactions which were manageable after amending the infusion schedule. Although BI 856826 will not undergo further clinical development, these results confirm CD37 as a valid therapeutic target in B cell NHL.

Safety and efficacy of faldaprevir in combination with pegylated interferon α-2b and ribavirin in Japanese patients with genotype-1 chronic hepatitis C virus infection.

AIM: We evaluated the safety and efficacy of the hepatitis C virus (HCV) NS3/4A A protease inhibitor faldaprevir plus pegylated interferon α-2b and ribavirin (PegIFNα-2b/RBV) in Japanese patients with HCV genotype-1 infection. METHODS: Treatment-naïve patients were randomized (1:1) to faldaprevir 120 mg q.d. for 12 or 24 weeks (response-guided therapy [RGT], n = 44), or faldaprevir 240 mg q.d. for 12 weeks (n = 43), each combined with PegIFNα-2b/RBV for 24 or 48 weeks (RGT). Response-guided therapy was based on early treatment success (HCV RNA <25 IU/mL at week 4 and <25 IU/mL undetected at week 8). Treatment-experienced patients received 240 mg q.d. for 24 weeks, plus PegIFNα-2b/RBV RGT (24 or 48 weeks, prior relapsers, n = 29) or PegIFNα-2b/RBV (48 weeks, 5 prior partial responders/breakthroughs, 10 prior null responders). The primary objective was safety; sustained virologic response 12 weeks post-treatment (SVR12) was a secondary end-point. RESULTS: All except one patient experienced drug-related adverse events. Adverse events led to faldaprevir discontinuation in 1 (2%), 13 (20%), and 3 (6.8%) patients on faldaprevir 120 mg, faldaprevir 240 mg 12 weeks, and faldaprevir 240 mg 24 weeks, respectively. The SVR12 rates were: 86% with faldaprevir 120 mg and 74% with faldaprevir 240 mg among treatment-naïve patients; and 86%, 60%, and 40% among prior relapsers, partial responders/breakthroughs, and null responders, respectively. CONCLUSIONS: In treatment-naïve Japanese patients, faldaprevir 120 mg q.d. plus PegIFNα-2b/RBV was better tolerated than faldaprevir 240 mg q.d. plus PegIFNα-2b/RBV, with at least comparable efficacy. In treatment-experienced patients, most prior relapsers achieved SVR12 with 24 weeks of faldaprevir 240 mg q.d. plus PegIFNα-2b/RBV. Clinicaltrials.gov NCT01579474.

Faldaprevir, pegylated interferon, and ribavirin for treatment-naïve HCV genotype-1: pooled analysis of two phase 3 trials.

INTRODUCTION & AIM: Faldaprevir is a potent once-daily (q.d.) hepatitis C virus (HCV) NS3/4A protease inhibitor. The STARTVerso1 and STARTVerso2 phase 3 studies evaluated faldaprevir plus peginterferon alfa-2a/ribavirin (PegIFN/RBV) in treatment-naïve patients with chronic HCV genotype-1 infection. MATERIAL AND METHODS: Patients were randomized 1:2:2 to receive placebo, faldaprevir 120 mg q.d. (12 or 24 weeks) or faldaprevir 240 mg q.d. (12 weeks) all with PegIFN/RBV (24-48 weeks). Faldaprevir 120 mg for 12 weeks only (STARTVerso1 only) required early treatment success (ETS, HCV RNA < 25 IU/mL at week 4 and undetected at week 8). All faldaprevir-treated patients with ETS stopped PegIFN/RBV at week 24. Primary endpoint: sustained virologic response 12 weeks post-treatment (SVR12). RESULTS: SVR12 rates were significantly higher for patients treated with faldaprevir 120 or 240 mg (72% and 73%, respectively) compared with placebo (50%); estimated differences (adjusted for trial, race, and genotype-1 subtype) faldaprevir 120 mg 24% (95% CI: 17-31%, P < 0.0001), faldaprevir 240 mg 23% (95% CI: 16-30%, P < 0.0001). Subgroup analyses consistently showed higher SVR12 rates for patients receiving faldaprevir compared with placebo. The incidence of adverse events (AEs) was similar in faldaprevir 120-mg and placebo groups and slightly higher in the faldaprevir 240-mg group. Serious Aes were reported in 6%, 7%, and 8% of patients in placebo, faldaprevir 120-mg, and faldaprevir 240-mg groups, respectively. CONCLUSION: Addition of faldaprevir to PegIFN/RBV increased SVR12 in patients with HCV genotype-1, and was well tolerated. Faldaprevir 120 mg is effective in the treatment of HCV genotype-1. ClinicalTrials.gov: NCT01343888 and NCT01297270.

STARTVerso1: A randomized trial of faldaprevir plus pegylated interferon/ribavirin for chronic HCV genotype-1 infection.

BACKGROUND & AIMS: The efficacy and tolerability of faldaprevir, a potent hepatitis C virus (HCV) NS3/4A protease inhibitor, plus peginterferon (PegIFN) and ribavirin (RBV) was assessed in a double-blind, placebo-controlled phase 3 study of treatment-naïve patients with HCV genotype-1 infection. METHODS: Patients were randomly assigned (1:2:2) to PegIFN/RBV plus: placebo (arm 1, n = 132) for 24 weeks; faldaprevir (120 mg, once daily) for 12 or 24 weeks (arm 2, n = 259); or faldaprevir (240 mg, once daily) for 12 weeks (arm 3, n = 261). In arms 2 and 3, patients with early treatment success (HCV-RNA <25 IU/ml at week 4 and undetectable at week 8) stopped all treatment at week 24. Other patients received PegIFN/RBV until week 48 unless they met futility criteria. The primary endpoint was sustained virologic response 12 weeks post-treatment (SVR12). RESULTS: SVR12 was achieved by 52%, 79%, and 80% of patients in arms 1, 2, and 3, respectively (estimated difference for arms 2 and 3 vs. arm 1: 27%, 95% confidence interval 17%-36%; and 29%, 95% confidence interval, 19%-38%, respectively; p < 0.0001 for both). Early treatment success was achieved by 87% (arm 2) and 89% (arm 3) of patients, of whom 86% and 89% achieved SVR12. Adverse event rates were similar among groups; few adverse events led to discontinuation of all regimen components. CONCLUSIONS: Faldaprevir plus PegIFN/RBV significantly increased SVR12, compared with PegIFN/RBV, in treatment-naïve patients with HCV genotype-1 infection. No differences were seen in responses of patients given faldaprevir once daily at 120 or 240 mg.

Effect of Steady-State Faldaprevir on Pharmacokinetics of Atorvastatin or Rosuvastatin in Healthy Volunteers: A Prospective Open-Label, Fixed-Sequence Crossover Study.

Faldaprevir (FDV) is a potent, orally administered inhibitor of hepatitis C virus protease. It inhibits multiple cytochrome P-450 enzymes and multiple membrane transporters. The objective of this study was to evaluate the effect of steady-state faldaprevir on the pharmacokinetics (PK) of a single dose of atorvastatin or rosuvastatin. In this single-center, open-label, fixed-sequence crossover study, 33 healthy adult male and female volunteers were given either atorvastatin 10 mg (n = 16) or rosuvastatin 10 mg (n = 17) on day 1. Subjects subsequently received 240 mg twice daily of faldaprevir (loading dose) on day 5, followed by 240 mg faldaprevir once daily from day 6 to day 10, with an additional single dose of atorvastatin (10 mg) or rosuvastatin (10 mg) given on day 10. PK samples for the statins were collected on days 1-3 and days 10-12. Concomitant administration with faldaprevir led to approximately 9-fold and 34-fold increases in AUC0-∞ and Cmax , respectively, of atorvastatin and approximately 15-fold and 33-fold increases in AUC0-∞ and Cmax , respectively, of rosuvastatin, compared with the statins given alone. Exposure to the major metabolites (ortho-hydroxyatorvastatin and N-desmethylrosuvastatin) was increased to a similar magnitude as that of the parent compounds. The marked drug-drug interaction observed is most likely related to the inhibitory effects of faldaprevir on transporters, particularly hepatic uptake transporters such as OTAP1B1 and OATP1B3. Given the significant increase in exposure to statins in healthy volunteers, coadministration of faldaprevir with statins should be avoided.

Pharmacokinetic analysis of nevirapine extended release 400 mg once daily vs nevirapine immediate release 200 mg twice daily formulation in treatment-naïve patients with HIV-1 infection.

BACKGROUND: VERxVE data showed non-inferior virologic efficacy with extended release nevirapine (NVP-XR) dosed 400 mg once daily (QD) versus immediate release nevirapine (NVP-IR) 200 mg twice daily in a double-blind, non-inferiority study in treatment-naïve HIV-1-positive patients. OBJECTIVE: To study the pharmacokinetics (PK) of the NVP formulations and identify possible associations with demographic factors. METHODS: Patients with viral load ≥1000 copies/mL and CD4+ count > 50- <400 cells/mm3 (males) and >50- <250 cells/mm3 (females) at screening received NVP-IR 200 mg QD during a 14-day lead-in and were then stratified by baseline viral load and randomized to NVP-XR or -IR. NVP trough concentrations at steady state (SS) (Cpre,ss,N) were measured up to week 48 for all participating patients. In a PK sub-study, SS parameters - AUC0-24, Cmax, Cmin, and peak-to-trough fluctuation were obtained and analyzed with relative bioavailability assessed at week 4 by plasma collection over 24 h. RESULTS: Trough concentrations were stable from week 4 to week 48 for all patients (n = 1011) with both formulations, with NVP-XR/IR ratios of 0.77-0.82. Overall, 49 patients completed the PK sub-study: 24 XR and 25 IR. NVP-XR showed less peak-to-trough fluctuation (34.5%) than IR (55.2%), and lower AUC0-24, Cmin, Cmax, and trough concentrations than IR. However, no effect of SS trough concentrations was found on the virologic response proportion at least up to 1000 ng/mL. No significant association was found between NVP PK and gender, race, and viral load. CONCLUSION: These data suggest NVP-XR achieves lower but effective NVP exposure compared with NVP-IR.

Steady-state pharmacokinetics of nevirapine extended-release tablets in HIV-1-infected children and adolescents: an open-label, multiple-dose, cross-over study.

BACKGROUND: To compare steady-state (ss) pharmacokinetic targets of nevirapine extended-release (NVP-XR) tablets once-daily (QD) with immediate-release (NVP-IR) tablet or oral suspension twice-daily in HIV-1-infected children and adolescents. METHODS: Phase I, open-label, multidose, cross-over study with optional extension phase, in 85 patients 3 to <18 years of age, previously on an NVP-IR-based regimen for ≥18 weeks with baseline viral load <50 copies/mL. Patients were stratified by age, treated with NVP-IR twice-daily for 11 days, then NVP-XR QD for 10 days. Cpre,ss (steady-state, predose concentrations) was obtained from all, and 12-hour NVP-IR and 24-hour NVP-XR steady-state pharmacokinetic profiles were obtained in the pharmacokinetic substudy. Viral loads, CD4 counts and adverse events (AEs) were monitored. RESULTS: Eighty patients completed the trial. Adjusted geometric mean (gMean) Cpre,ss for NVP-XR and NVP-IR exceeded the target of 3000 ng/mL, and the adjusted gMean NVP-XR:NVP-IR ratio (90% confidence interval) for QD normalized and un-normalized Cpre,ss were 91.2% (83.5-99.6%) and 91.8% (83.7-100.7%). gMean 24-hour area under the curve at steady-state NVP-XR:NVP-IR for un-normalized dose was 90.4% and un-normalized Cpre,ss NVP-XR:NVP-IR were 91.0%, 81.9% and 103.7% for the 3 age groups, 3 to <6, 6 to <12 and 12 to <18 years, respectively. gMean values indicated no exposure to subtherapeutic NVP concentrations and viral suppression was adequate and maintained in all QD groups. Most AEs were mild and similar between age groups. No serious or Division of AIDS Grade 4 AEs or AE related treatment discontinuations occurred. CONCLUSIONS: NVP-XR exhibited adequate trough concentrations with equivalent area under the curve at steady-state relative to NVP-IR. NVP-XR was well-tolerated and is a valuable treatment option for HIV-infected children and adolescents.

Bioavailability of extended-release nevirapine 400 and 300 mg in HIV-1: a multicenter, open-label study.

BACKGROUND: Nevirapine (NVP) is a widely used non-nucleoside reverse transcriptase inhibitor. A once-daily extended-release (XR) formulation would potentially increase adherence and thus efficacy. OBJECTIVE: The aim of this study was to investigate the steady-state bioavailability of 2 once-daily tablet formulations of NVP XR (containing 25% or 20% hypromellose; NVP XR25 and NVP XR20, respectively) in 400- or 300-mg tablets compared with twice-daily immediate-release (IR) NVP 200-mg tablets. METHODS: This Phase Ib multinational, multicenter, open-label trial was conducted in patients aged 18 to 60 years, infected with HIV-1 (viral load, ≤50 copies/mL), and treated for ≥12 weeks with twice-daily NVP IR 200 mg. Patients were switched to NVP XR25 400 or 300 mg or NVP XR20 400 or 300 mg for 19 days. Plasma samples were collected over 24-hour periods at steady state. Primary end points were AUC(0-24,ss), C(max,ss), and C(min,ss), analyzed using an ANOVA statistical model on the logarithmic scale and 2-sided 90% CI. Sample size was determined assuming an intrasubject %CV of 20% for C(max). Adverse events (AEs) and viral loads were monitored. RESULTS: Ninety-two patients were enrolled (NVP XR25 400 mg, 24 patients; NVP XR20 400 mg, 24; NVP XR25 300 mg, 21; NVP XR20 300 mg, 23). Compared with NVP IR, the AUC(0-24,ss) values of the NVP XR formulations were lower (test/reference ratios: 79.5% [90% CI, 73.0-86.7; P = 0.544], 71.0% [90% CI, 63.3-79.7; P = 0.956], 90.3% [90% CI, 80.4-101.4; P = 0.044], and 83.7% [90% CI, 77.9-89.9; P = 0.148] with NVP XR25 400 mg, NVP XR20 400 mg, NVP XR25 300 mg, and NVP XR20 300 mg, respectively). The relative bioavailability of NVP XR25 was greater compared with that of NVP XR20. C(max,ss) values were lower with all NVP XR formulations compared with NVP IR. For C(min,ss), NVP XR25 400 and 300 mg were not significantly different from NVP IR, with 90% CIs within the range of 80% to 125% (P = 0.039 and P = 0.017, respectively). All AEs were mild or moderate, with no significant differences between treatment groups. No virologic failures (viral load, >50 copies/mL over 2 consecutive readings) were observed. CONCLUSIONS: Extent of bioavailability was lower and t(max,ss) was delayed with all NVP XR formulations compared with NVP IR. The bioavailability of the NVP XR25 formulations was greater than that of the NVP XR20 formulations. C(min,ss) with NVP XR25 was similar to that with NVP IR. All of the NVP XR formulations were well tolerated. The 400-mg NVP XR25 formulation was selected for further development.

Efficacy and safety of nevirapine extended-release once daily versus nevirapine immediate-release twice-daily in treatment-naive HIV-1-infected patients.

BACKGROUND: This study (VERxVE) compared the efficacy and safety of the new nevirapine extended-release (NVP XR) formulation dosed once daily with NVP immediate release (IR) twice daily in treatment-naive patients. METHODS: Randomized, double-blind, double-dummy, parallel group study of HIV-1-infected adult patients with baseline viral load (VL) ≥ 1,000 copies/ml and CD4(+) T-cell count of >50-<400 (males) and >50-<250 cells/mm(3) (females). Patients stratified by baseline VL (≤ 100,000/>100,000 copies/ml) were randomized 1:1 to NVP XR 400 mg once daily (plus placebo) or NVP IR 200 mg twice daily (plus placebo), both combined with tenofovir disoproxil fumarate (TDF) 300 mg and emtricitabine 200 mg once daily. Primary endpoint was sustained virological response (<50 copies/ml) through week 48 using the time to loss of virological response algorithm. Non-inferiority of NVP XR to NVP IR was tested using Cochran's statistic incorporating baseline VL stratum with pre-specified, non-inferiority margin of -10%. RESULTS: Among 1,011 patients randomized and treated, virological response at week 48 was 81.0% (409/505) for NVP XR and 75.9% (384/506) for NVP IR with adjusted difference of 4.9% in favour of NVP XR (95% CI -0.1-10.0%), demonstrating non-inferiority of NVP XR to NVP IR. This finding was supported by secondary endpoints. The safety profile of NVP XR was similar to NVP IR, but showed numerically fewer treatment-related adverse events. CONCLUSIONS: NVP XR in combination with TDF and emtricitabine was shown to be non-inferior in efficacy to NVP IR with a similar safety and adverse event profile, with the potential for the added convenience of once-daily dosing. TRIAL REGISTRATION: ClinicalTrials (NCT): NCT00561925.

Assessment of nevirapine bioavailability from targeted sites in the human gastrointestinal tract.

This study investigated absorption of nevirapine (NVP) from targeted sites of the gastrointestinal tract using remotely activated capsules and gamma scintigraphy. A total of 24 participants were randomized to receive 50 mg NVP orally as a suspension or via remotely activated capsules for release into the ascending colon. The 24 participants were then rerandomized into parallel groups of n = 8 for drug release into the ileum, jejunum, or descending colon. The mean gastric emptying time of capsules ranged from 0.88 to 3.35 hours. The small intestinal and colon transit time ranged from 4.08 to 7.76 hours and 17.6 to 21.2 hours, respectively, and capsule recovery time ranged from 27.6 to 34.4 hours. The relative bioavailability ratio of NVP in the jejunum was 1.06 (90% confidence interval [CI]: 1.00-1.12) compared to suspension. In the ileum, ascending colon, and descending colon, bioavailability decreased to 0.89 (0.80-0.99), 0.82 (0.71-0.95), and 0.58 (0.22-1.53), respectively. The absorption rate decreased by approximately 10-fold from the jejunum (3.83 h(-1)) to the descending colon (0.338 h(-1)), and t(max) increased from 2.42 hours (jejunum) to 16.3 hours (descending colon). Overall, NVP is absorbed from all 4 sites of the gastrointestinal tract, and the rate of absorption decreased from the jejunum to the descending colon. Relative bioavailability of NVP was in the order of jejunum > ileum > ascending colon > descending colon.