Merck (MRK) Presents Results from Three MK-3682B Phase 2s; High SVR Rates Noted

November 14, 2016 6:29 AM EST

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Merck (NYSE: MRK) announced the presentation of results from three Phase 2 clinical trials evaluating MK-3682B (MK-3682/grazoprevir/ruzasvir1), the company’s investigational all-oral, triple-combination regimen for the treatment of chronic hepatitis C (HCV) infection (informally referred to as MK3). Results from Part B of C-CREST 1 & 2 demonstrated high rates of sustained virologic response2 (SVR) 12 weeks after the completion of therapy (SVR12, considered virologic cure) in patients with chronic HCV genotype (GT) 1 or GT3 infection who received eight weeks of treatment with MK-3682B. Findings from C-CREST 1 & 2 Part B also demonstrated high rates of SVR12 in GT1, GT2 and GT3-infected patients who received MK3 for 12 or 16 weeks. Findings from Part C of C-CREST 1 & 2 and interim results from the ongoing C-SURGE study showed high rates of SVR12 and SVR8, respectively, in chronic HCV patients who had failed prior treatment with investigational or approved direct-acting antiviral regimens. These results will be announced in oral presentations at The Liver Meeting® 2016 today (C-CREST 1 & 2 Parts B and C) and tomorrow (C-SURGE).

“Across the chronic hepatitis C treatment landscape, incredible progress has been made in a remarkably short amount of time, but there remains a need for more options, particularly for patients who do not achieve sustained virologic response with treatment regimens available today,” said Dr. Eliav Barr, senior vice president, global clinical development, infectious diseases and vaccines, Merck Research Laboratories. “The strong findings observed following treatment with MK-3682B are an encouraging step towards Merck’s goal of developing and delivering a shorter-duration, pan-genotypic next-generation treatment regimen for more patients with chronic hepatitis C infection.”

C-CREST 1 & 2 Part B Overview and Findings

Part B of C-CREST 1 & 2 – ongoing, open-label Phase 2 clinical trials – was designed to evaluate the safety and efficacy of MK-3682B in patients with chronic HCV GT1, GT2 or GT3 infection, with or without cirrhosis. Patients with GT2 or GT3 infection received MK-3682B with or without RBV. All patients with GT1 or GT2 infection were treatment-naïve. Fifty six percent (189/337) of patients with GT3 infection were treatment naïve and 44 percent (148/337) were previously treated with peginterferon/ribavirin (RBV). The primary endpoint of the study was the proportion of patients in each treatment arm who achieved SVR12.

Eight weeks of treatment with MK-3682B resulted in SVR12 rates of 95 percent, 86 percent and 95 percent in GT1, GT2 and GT3 patients, respectively. A 12-week treatment duration resulted in high SVR12 rates in all genotypes (GT1, 99%; GT2, 97%; GT3, 97%). Efficacy was comparable in patients with and without cirrhosis. There were no virologic failures in the patients with GT1 or GT2 infection who received 12 weeks of MK-3682B. Efficacy results are presented in the table below. Results from Part A of C-CREST 1 & 2 were previously reported at The Liver Meeting® in November 2015.

Summary of SVR12 Findings

Population N MK-3682B

+/- RBV

8 weeks

MK-3682B

+/- RBV

12 weeks

MK-3682B

+/- RBV

16 weeks

GT1a 90 93% (39/42) 98% (47/48) -
GT1b 86 98% (45/46) 100% (40/40) -
GT2 151 86% (54/63) 97% (60/62) 100% (26/26)
GT3* 337 95% (98/103) 97% (155/159) 96% (72/75)

*28 percent (29/103), 36 percent (58/159) and 81 percent (61/75)of patients with GT3 infection receiving eight, 12 or 16 weeksof therapy, respectively, were previously treated with peginterferon/RBV

Among patients who received at least one dose of MK-3682B with or without RBV, the overall most common adverse events (AEs) reported (greater than 10% incidence in either treatment arm) were headache (22%), fatigue (19%) and nausea (13%). There were two drug-related serious AEs, both considered related to RBV only. Nine patients discontinued study drug due to AEs, four of whom discontinued RBV only. One patient died due to AEs not related to the study drug.

“As a scientist and physician who regularly treats patients with chronic hepatitis C, the importance of continuing to research this complex disease and its many complications is evident,” said Dr. Eric Lawitz, vice president, scientific and research development, The Texas Liver Institute and clinical professor of medicine, The University of Texas Health Science Center, San Antonio. “The virologic cure rates observed in Part B of C-CREST 1 & 2 clearly demonstrate the potential for MK3 and support further study of this investigational regimen.”

C-SURGE Overview and Preliminary Findings

C-SURGE is an ongoing, open-label Phase 2 clinical trial designed to evaluate MK-3682B with or without RBV in chronic HCV GT1 patients who previously failed therapy with either ledipasvir/sofosbuvir (LDV/SOF) or ZEPATIER™ (elbasvir and grazoprevir). The study enrolled 94 patients randomized to receive 16 weeks of MK-3682B plus RBV (n=45) or 24 weeks of MK-3682B without ribavirin (n=49); one patient in the 16 week arm withdrew prior to starting treatment. Of the 93 patients who received treatment in this study, 61 percent (57/93) had previously received 12 to 24 weeks of treatment with LDV/SOF; 15 percent (14/93) had received 8 weeks of LDV/SOF; and 24 percent (22/93) had received 12 weeks of ZEPATIER. A majority of patients (84%, 78/93) had at least one baseline NS5A resistance-associated variant (RAV) at positions 28, 30, 31 or 93.

Interim results from the modified full analysis set (mFAS), which excludes one patient in the 16-week arm who withdrew due to administrative reasons after receiving three doses of study medication, show all patients (43/43) who have completed treatment with MK-3862B plus RBV for 16 weeks achieved SVR8. All patients (49/49) in the mFAS who received MK-3682B for 24 weeks have completed treatment and remain subject to follow-up; the interim results show of those in the 24-week arm who have reached follow-up weeks four and eight, 100 percent have achieved SVR4 (38/38) and SVR8 (30/30), respectively. SVR12 is the primary outcome measure of this ongoing trial. Final results will be presented at a future scientific congress.

Among patients who received at least one dose of MK-3682B with or without RBV, the overall most common AEs reported were fatigue (35%), headache (13%), diarrhea (9%), rash (9%) and pruritus (5%). There were no drug-related serious AEs, and no patients discontinued due to a drug-related AE.

C-CREST 1 & 2 Part C Overview and Findings

Part C of C-CREST 1 & 2 was designed to evaluate retreatment with MK-3682B plus RBV for 16 weeks among patients who previously failed an investigational triple-therapy regimen (MK-3682/grazoprevir/ruzasvir or MK-3682/grazoprevir/elbasvir). The study enrolled 24 patients with GT1 (n=2), GT2 (n=14) or GT3 (n=8) infection. All patients (23/23) who completed treatment achieved SVR12. One GT2 patient discontinued treatment after a single dose due to drug-related serious AEs. Among patients who received at least one dose of MK-3682B plus RBV, the most common AEs reported (greater than 20% incidence) were headache (33%), fatigue (25%), nausea (25%), rash (21%) and insomnia (21%).

About MK-3682B

MK-3682B (informally referred to as MK3) is Merck’s investigational triple-combination therapy in Phase 2 development for the treatment of chronic HCV infection. MK-3682B combines an HCV nucleotide analogue NS5B polymerase inhibitor (MK-3682), an HCV NS3/4A protease inhibitor (grazoprevir, MK-5172) and an HCV NS5A inhibitor (ruzasvir, MK-8408).

About ZEPATIER™ (elbasvir and grazoprevir) 50 mg/100mg tablets

ZEPATIER is a fixed-dose combination product containing elbasvir, an HCV NS5A inhibitor, and grazoprevir, an HCV NS3/4A protease inhibitor. ZEPATIER is indicated with or without ribavirin (RBV) for treatment of chronic HCV genotypes 1 or 4 infection in adults.

Selected Safety Information about ZEPATIER

ZEPATIER is not for use in patients with moderate or severe hepatic impairment (Child Pugh B or C). ZEPATIER is also not for use with organic anion transporting polypeptides 1B1/3 (OATP1B1/3) inhibitors (e.g., atazanavir, darunavir, lopinavir, saquinavir, tipranavir, cyclosporine), strong cytochrome P450 3A (CYP3A) inducers (e.g., carbamazepine, phenytoin, rifampin, St. John’s Wort), and efavirenz. If ZEPATIER is administered with RBV, healthcare professionals should refer to the prescribing information for RBV as the contraindications, warnings and precautions, adverse reactions and dosing for RBV also apply to this combination regimen.

Elevations of alanine transaminase (ALT) to greater than 5 times the upper limit of normal (ULN) occurred in 1% of subjects, generally at or after treatment week 8. These late ALT elevations were typically asymptomatic and most resolved with ongoing or completion of therapy. Healthcare professionals should perform hepatic lab testing on patients prior to therapy, at treatment week 8, and as clinically indicated. For patients receiving 16 weeks of therapy, additional hepatic lab testing should be performed at treatment week 12.

Patients should be instructed to consult their healthcare professional without delay if they have onset of fatigue, weakness, lack of appetite, nausea and vomiting, jaundice or discolored feces. Healthcare providers should consider discontinuing ZEPATIER if ALT levels remain persistently greater than 10 times ULN. ZEPATIER should be discontinued if ALT elevation is accompanied by signs or symptoms of liver inflammation or increasing conjugated bilirubin, alkaline phosphatase, or international normalized ratio.

The concomitant use of ZEPATIER with certain drugs may lead to adverse reactions or reduced therapeutic effect due to drug interactions. Certain strong CYP3A inhibitors may increase the plasma concentration of ZEPATIER, leading to possibly clinically significant adverse reactions. Moderate CYP3A inducers may decrease the plasma concentration of ZEPATIER, leading to reduced therapeutic effect and possible development of resistance. Coadministration of ZEPATIER with these drugs is not recommended. Physicians should consult the Prescribing Information for potential drug interactions.

In subjects receiving ZEPATIER for 12 weeks, the most commonly reported adverse reactions of all intensity (greater than or equal to 5% in placebo-controlled trials) were fatigue, headache and nausea. In subjects receiving ZEPATIER with RBV for 16 weeks, the most commonly reported adverse reactions of moderate or severe intensity (greater than or equal to 5%) were anemia and headache.



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