I’ve been busy with other things offline since the last blog update from the American Society of Hematology (ASH) meeting in San Diego, but will be catching up on my notes from the conference over the next few days.
In addition, my colleague Pieter Droppert has already posted his topline impressions of the meeting on the companion Biotech Strategy Blog, which readers may be interested in:
Meanwhile, I thought it would be a good idea to look at the pipeline developments in non-Hodgkin’s lymphomas (NHL) that I particulalry liked at ASH:
Pieter’s choice of PI3K as a hot topic turned out to be rather prescient given that:
a) Intelikine announced last night that the company is being bought by Millennium-Takeda in a deal worth $190M upfront with $120M in additional milestone payments. This is a great transaction all around, enabling clinical development to now begin for Intellikine’s two remaining PI3K-mTOR and selective isoform inhibitors and since Takeda have research facilities locally in San Diego, this will enable work to continue with minimum fuss and relocation.
b) As of this morning, Exelixis announced they have licensed their PI3K-delta inhibitor in preclinical development to Merck. This deal features an upfront payment of $12 million, but the company will be eligible for potential development and regulatory milestone payments for multiple indications of up to $239 million in the future.
Another PI3K inhibitor in the news is Calistoga’s CAL-101 (now owned by Gilead), a delta selective isoform inhibitor being evaluated in indolent NHL. At this meeting, the phase I data was presented in a poster. The patients enrolled to date (n=37) included those with follicular lymphoma, small lymphocytic leukemia and marginal zone lymphomas, all of whom had received prior therapy for their disease. In this study, CAL-101/GS-1101 was given in combination with rituximab and/or bendamustine to determine the safety profile.
The big question is whether the combination with chemoimmunotherapies would lead to added or overlapping toxicities – the authors, de Vos et al., concluded that answer was no and a good efficacy signal was seen:
“GS-1101-based combination therapy with rituximab and/or bendamustine offers major and rapid reductions in lymphadenopathy.”
On the basis of this study and a prior phase I trial that determined the dose (150mg/BID), further continuation of the program in this indication appears warranted:
“The data from this trial will be used to design Phase 3 combination studies of GS-1101 in patients with iNHL.”
Anti-CD20 monoclonal antibodies
Rituximab was the first targeted cancer drug following its approval back in 1997 and has shown how important targeting CD20 has been in lymphomas and more recently, chronic lymphocytic leukemia (CLL). At this meeting, we saw an interesting new development in lymphomas from Roche/Genentech in GA101 (obinutuzumab). This is essentially a follow-on biologic to rituximab. In a previous post prior to ASH, I looked at the key questions that need to be addressed in order to displace rituximab, namely more activity in rituximab refractory patients, more efficacy/better side effect profile up-front or broader activity across several diseases.
What are the key differences between rituximab and obinutuzumab you might ask and does this impart any clinical benefit?
Well, rituximab is a humanised type I monoclonal antibody, whereas obinutuzumab is a humanised type II glyco-engineered antibody, both target CD20. What’s the difference between Type I and II? Well, according to Robak, 2009:
“GA-101 binds with high affinity to the CD20 type II epitope, resulting in the induction of antibody-dependent cytotoxicity that is 5- to 100-fold greater than observed upon treatment with rituximab.”
The proof of the pudding is always in the clinical data, especially randomised head-to-head trials. There were over a dozen abstracts on GA101 at ASH, but the most important one in this context was a phase II GAUSS trial from Sehn et al., which randomised patients with indolent B-Cell NHL to receive either rituximab or obinutuzumab in the relapsed setting:
And the result? The authors concluded that:
“Treatment with GA101 in patientss with relapsed NHL resulted in higher response rates compared to rituximab as assessed by both investigators and the IRF at an early time point.
GA101 was well tolerated, although a higher rate of IRRs was noted, the majority were grade 1/2 in severity and did not result in significant differences in treatment discontinuation.”
Where IRR is infusion related reactions.
This data is promising for obinutuzumab, but still very early – we will still need to see what happens in a larger scale phase III trial with more patients before we can draw more definitive conclusions. That said, I found the GAUSS trial data very encouraging indeed.
Bruton’s Kinase Inhibitors
In the first update, I highlighted how Bruton’s Kinase inhibition (BTK) was one of the exciting new emrging pathways in chronic lymphocytic leukemia (CLL), but new data was also presented on the leading BTK inhibitor, PCI-32765 (Pharmacyclics/J&J), in lymphomas.
The preliminary phase II data in mantle cell lymphoma (MCL) presented by Wang et al., in 48 patients (29 bortezomib-naive, 19 bortezomib-exposed) with a median of two prior treatment regimens (range:1-5).
Initial efficacy data was reported:
“The objective response rate (ORR) is 67% (16/24); ORR is 58% (7/12) in the bortezomib-naive cohort and 75% (9/12) in the bortezomib-exposed cohort.”
The side effect profile seen to date was also described:
“Serious AEs (SAEs) have occurred in 8/39 patients (21%); 2 SAEs (1 rash, 1 febrile neutropenia) were considered potentially related to PCI-32765.”
I thought these results were encouraging – with good tolerability and encouraging signs of efficacy – certainly worthy of exploring in a randomised phase III trial in this indication. This is an agent we are probably going to hear a lot more about in the near future.
There were a lot of new developments emerging at this meeting, particularly in the poster sessions and also in both phase I and II trials. It was impossible to keep up with everything, so this post is just a flavour of some of the abstracts either of us did manage to take in.
The challenge, as always, with ASH is their insistence of holding all the critical oral sessions on biology and therapy in leukemias, lymphomas, myelomas and myeloproliferative diseases almost on a single day, making it absolutely impossible to see/hear all the new and exciting data. Monday is, therefore, always a manic day. It’s a strange contrast from the long lulls on the Sunday where some of the oral sessions could have been hosted, perhaps the biology sessions, thereby freeing up a more flexible schedule for the clinical data on Monday. There is some weirdness and also dismay in seeing a biology and clinical session for the same topic (eg CML, Multiple Myeloma, Lymphomas or FLT3 in AML) clashing. Not everyone is a specialist, certainly the community oncologists who attend are not. This is silly scheduling and means that people presenting in a biology session often miss the clinical update for a trial they were a PI in, while attendees like me are regretably forced to choose from one or the other.
Sadly, not everyone can stay until Tuesday morning when a few more key oral sessions that include new data are held, for a meeting that began on Friday. This is issue compounded by no virtual meeting facility, one of ASCO, AACR, ECCO and even the NY Chemotherapy Symposium’s great online service whereby you can catch up with sessions you missed later. For me, this is a critical and integral part of modern cancer meetings.
I hate missing out on great or important data and hope that ASH will seriously consider virtual meeting access for future meetings – it really does help attendees – otherwise if you didn’t catch the sessions they are gone forever! Personally, I was still watching (and enjoying) presentations I missed at AACR and ASCO in July, long after both meetings finished, and really appreciated their excellent webcasts/virtual meetings.
One of the sad things for me was it turned out to be the first time in many years that I skipped the Plenary session as there were some odd choices this year that simply didn’t resonate with me. For example, making Mylotarg, a drug withdrawn by the FDA recently, one of the meeting highlights made little sense to me because:
a) it will have no immediate clinical or even scientific impact for the practising oncologist and
b) there were far more dramatic results that I thought were worthy of broader dissemination
Overall though, this was a good ASH meeting from the point of view of exciting new data in phase I and II trials; clearly the oncology pipelines are beginning to show some early promise, but it was disappointing not to see more of them prominently highlighted. There were quite a few other abstracts I liked, but this overview should give a good flavour of some of the novel agents emerging for the treatment of NHL.
For those wanting information on Hodgkins Lymphomas, I’ll cover those in a separate post as there was too much data to cover both in one post.