Combination of Nilotinib and Pegylated Interferon Alfa-2b Results in High Molecular Response Rates in Chronic Phase CML: Interim Results of the ALLG CML 11 Pinnacle Study

Alfa Interferon, commonly used in chronic phase chronic myeloid leukemia (CML-CP) in the pre-imatinib era, was able to induce a cytogenetic response in a minority of patients (pts). Pegylated interferon (Peg-IFN) is better tolerated than IFN, and increases molecular response rates when used in combination with imatinib (IM) compared with IM monotherapy (Preudhomme NEJM 2010). The phase II Pinnacle (ALLG CML 11) study evaluated the tolerability and molecular response rate of nilotinib (NIL) with Peg-IFN alfa-2B (PegIntron, MSD) in de novo CML-CP. Pts were screened for cardiac / vascular disease and associated risk factors at baseline (EKG, left ventricular ejection fraction, arterial duplex of carotids and lower limbs, blood HbA1c and lipid profiles). Those with uncontrolled vascular risk factors (diabetes, hypertension, dyslipidemia) or a history of vascular events were excluded. Eligible pts received NIL 300mg BID alone for the first 3 months (mths). PegIntron was then added at 30mcg/week in pts without persistent hematological toxicities, increasing to 50mcg/week as tolerated over the following mth. Combination therapy continued until 24 mths, when pts reverted to TKI monotherapy. Switching to IM 400-600mg QD was allowed for pts with persistent grade II or any grade III/IV toxicity from NIL.. Sixty pts were enrolled from 12 Australian centres. Median age was 48.5 years (range 19-72); 45% were female. Sokal risk was low in 43% and high in 18%. Median follow up (FU) was 28 mths (16-51). Data is presented on an intention to treat basis. Figure 1a shows BCR-ABL1 transcript levels over time. The co-primary end points are MMR (BCR-ABL1 ≤0.1% IS) AT 12 mths and MR4.5 (BCR-ABL1 ≤0.0032% IS) at 24 mths. At 12 mths, MMR and MR4.5 rates were 76.7% (95% CI 63.4-87%). and 43.4% (95% CI 30.1-57.3%), respectively. In 40 evaluable pts at 24 mths, MR4.5 was 50% (95% CI 29.9-70.1%). The median time to MMR and MR4.5 was 5.8 mths and 18 mths respectively for pts achieving these responses (Figs 1B & C). Six pts (10%) had BCR-ABL1 ≥10% at 3 mths - 2 of whom had multiple dose interruptions due to toxicity; 3/6 have since achieved MMR, 1 has BCR-ABL Dose intensities of NIL were assessed in 3 mth blocks. Median and lower quartile NIL dose intensity was 600mg/d for all 3 mth blocks up to mth 24, except for the lower quartile NIL dose of 567mg for the first 3 mths. Eight pts (13%) did not commence Pegintron (2 due to persistent haem toxicities, 4 from GI disturbance, liver/pancreatic enzyme derangements, and 2 from pt preference). Considering Pegintron as a product of protocol assigned dose and duration, adjusted for time from study entry, 22 pts (37%) received >90% of their assigned dose, 13 (22%) received between 50-90% and 25 pts (41%) received Grade III/IV adverse events (AE) attributed to NIL were increased lipase and neutropenia (each 12%), pancreatitis (6%), thrombocytopenia and rash (each 5%). Three thrombotic events occurred: ischemic colitis in a patient on IM monotherapy, femoral artery thrombosis in a 56yo man after 2.5 yrs of NIL, and coronary disease in a 51yo man after 4 yrs of NIL. Grade III/IV AEs attributed to Pegintron were neutropenia (10%), and myalgia, depression and rash (4% each); other common AEs included fatigue (35%), myalgia (23%), flu-like symptoms (21%) and depression (17%). Ten pts (13%) have withdrawn from study: 2 withdrew consent, 5 due to toxicity (pancreatitis, GI upset, rash, high amylase and fatigue), and 3 for failing to consistently achieve BCR-ABL 90% of assigned NIL/IM and Pegintron doses. This interim analysis suggests that combination therapy with NIL and Peg-IFN leads to favourable rates of molecular responses when compared with with NIL monotherapy (Table 1). While the majority of patients did not durably tolerate full dose Pegintron, there was minimal interference with TKI dose intensity. Longer term results, and impact upon treatment free remission outcome of this combination is awaited. Disclosures Yeung: Pfizer: Honoraria; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Specialised Therapeutics Australia: Honoraria; Amgen: Honoraria. Grigg: Takeda: Membership on an entity9s Board of Directors or advisory committees; Roche: Membership on an entity9s Board of Directors or advisory committees; BMS: Membership on an entity9s Board of Directors or advisory committees; Gilead: Membership on an entity9s Board of Directors or advisory committees. Shanmuganathan: Janssen: Honoraria; Royal Adelaide Hospital Research Fund: Other: Scholarship; Novartis: Honoraria, Other: Travel sponsorship; Bristol-Myers Squibb: Honoraria, Other: Travel sponsorship. Reynolds: Novartis: Equity Ownership, Other: former employee of Novartis AG and holds stock in the company. . Ross: BMS: Honoraria; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Research Funding. Yong: Celgene: Research Funding; Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding. White: Novartis: Honoraria, Research Funding; BMS: Research Funding. Branford: Qiagen: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Cepheid: Honoraria; BMS: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Hughes: BMS: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity9s Board of Directors or advisory committees.