Effect of BBP 418, a chemically synthetised tetrodotoxin derivative, in pain therapy

Pritsana Khamchaew, Edwin ten Winkel, bbPharma

BBP418 is chemically synthetised but identical to one of the main compounds of tetrodotoxin, the toxin of the pufferfish or blowfish (Tetraodontidae). BBP418 is a sodium channel blocker, that selectively blocks off the voltage-sensitive sodium channels of excitable tissues and neuronal transmission in skeletal muscles. It is being developed as a potent pain-killer and is currently undergoing Phase II trials in 30 patients. Administration of a few microgram appear to be effective in about 75% of subjects.
Tetradotoxin is complex in structure by small molecule standards and contains a guanidinium moiety. The guanidinium ion is able to enter cells via the voltage sensitive Na+ channels, which are critical for cellullar signalling pathways (e.g. transmission of impulses and the mediation of many cell functions). It is likely that this imidazole ring is the part of the molecule that lodges in the channel leaving the rest of the molecule blocking its outer mouth. Their association and dissociation are independent of whether the channel is open or closed. When a neuron (nerve cell) is sending a message, tiny pores or channels in the neuron's membrane open up to let sodium ions enter the cell. Tetrodotoxin (puffer fish toxin) blocks these tiny pores, which in turn prevents any signalling in the nervous system. The result is rapid paralysis and possibly death.
BBP418 differs from other painkillers in that it doesn't have the same side effects as e.g. morphine and its derivatives, there are no known significant interactions with other medicines and is not addictive. It is up to 3,200 times stronger than morphine.
Effects in similar compounds (Tectin®) have shown initial promising but ultimately disappointing effects in the treatment of cancerpatients. BBP418 however is not identical to Tectin® and is believed to hold promise for the treatment of cancerpain as well.

Note: Tetradotoxin is also found in other animals e.g., the California newt and the eastern salamander

Effects of low concentrations of tetradotoxin on rat trigeminal ganglion neurons

Field J. Puffer Fish Poisoning. Journal of Accident & Emergency Medicine.15: (5) 334-336 Sep 1998

Fuchi Y, Hoashi K, Akaeda H, Makino Y, Noguchi T. Anatomical Distribution and Seasonal Variation of Toxicity of Puffer Fish, "Hoshifugu" Arothron firmamentum specimens collected from the Bungo Channel, Oita. Journal of The Food Hygienic Society of Japan. 39: (6) 421-425 DEC 1998

Lin SJ, Chai TJ, Jeng SS, Hwang DF.Toxicity of the puffer Takifugu rubripes cultured in northern Taiwan.Fisheries Science. 64: (5) 766-770 Oct 1998

Malpezzi ELA, deFreitas JC, Rantin FT. Occurrence of toxins, other than paralysing type, in the skin of tetraodontiformes fish. Toxicon. 35: (1) 57-65 Jan 1997

Matsui T, Taketsugu S, Kodama K, Ishii A, Yamamori K, Shimizu C. Studies on the Toxification of Puffer Fish .1. Production of Tetrodotoxin by the Intestinal Bacteria of a Puffer Fish, Takifugu niphobles. Nippon Suisan Gakkaishi. 55: (12) 2199-2203 Dec 1989

Matsumura K.A. Monoclonal-Antibody Against Tetrodotoxin That Reacts to The Active Group For the Toxicity. European Journal of Pharmacology-Environmental Toxicology and Pharmacology Section.293: (1) 41-45 May 26 1995

Matsumura, K.Tetrodotoxin concentrations in cultured puffer fish, Fugu rubripes. Journal of Agricultural and Food Chemistry. 44: (1) 1-2 Jan 1996

Matsumura K. Production of tetrodotoxin in puffer fish embryos. Environmental Toxicology and Pharmacology.6: (4) 217-219 Dec 1998

Nagashima Y, Hamada Y, Ushio H, Nishio S, Shimakura K, Shiomi K. Subcellular Distribution of Tetrodotoxin in Puffer Fish Liver. Toxicon. 37: (12) 1833-1837 Dec 1999.

Saito T, Noguchi T, Shida Y, Abe T, Hashimoto K. Screening of Tetrodotoxin and Its Derivatives in Puffer-Related Species. Nippon Suisan Gakkaishi. 57: (8) 1573-1577 Aug 1991

Sun K, Wat J, So P. Puffer Fish Poisoning. Anaesthesia and Intensive Care. 22: (3) 307-308 Jun 1994

Sun K O. Management of Puffer Fish Poisoning. British Journal of Anaesthesia. 75: (4) 500-500 Oct 1995

Yang C C, Han K C, Lin T J, Tsai W J, Deng J F. An Outbreak of Tetrodotoxin Poisoning Following Gastropod Mollusk Consumption. Human & Experimental Toxicology. 14: (5) 446-450 May 1995

Yu CF, Yu PHF. A Preliminary Study of Puffer Fishes And Their Toxins Found in Hong Kong Waters. Journal of The Food Hygienic Society of Japan 38: (6) 460-463 Dec 1997

Life extending properties of BBP750 in Caenorhabditis elegans

Lam Hoi-ka, E. ten Winkel, bbPharma

Certain drugs such as mianserin have been reported to extend the lifespan in worms by 30%. We have tested BBP750 a serotonin modulator with octopamine inhibiting effects.
Caenorhabditis elegans on BBP750 enhanced diet showed a 25% boost in lifespan compared to C. elegans on a regular diet (bacterial lawn grown on an agar plate, with and without BBP750 enrichment). No Dauer stadia were seen

Interestingly, effects from other studies on BBP750 show that rats have slightly decreased food-intake compared to rats on a regular diet.

Conotoxin in pain transmission

Pritsana Khamchaew, Edwin ten Winkel, bbPharma

In the vertebrate nervous system the calcium influx in the pre-synaptic end of the nerve fiber leads to a release of neurotransmitter in the synaptic cleft. Specific ion channels facilitate the calcium influx and the synaptic signal transmission.
The conopeptide reversibly antagonises -highly specifically- a special type of calcium channel (the N-Type), that can be found in a high density in the Central Nervous System and that is responsible for pain transmission.
Our conotoxin, a nerve agent, binds to and blocks these N-Type calcium channels and thus blocks the release of neurotransmitter. The nerve impuls is thus interrupted pre-synaptically. This effect -in contrast to morphine- is immediate and complete.

Normalisation of CD4 count in an individual with HIV

Pritsana Khamchaew, Edwin ten Winkel, bbPharma

A 35 year old Chino-Thai male with previously diagnosed HIV and onset of AIDS was included in a clinical trial investigating effect of BBP153 on CD4 count in patients with HIV. Baseline value upon entry of the trial for this patient was 221 CD4 cells/mm3. He received 1 gram of BBP153 daily. CD4 count was repeated after 8 weeks and 912 CD4 cells/mm3 were found while symptoms were cleared. Normal CD4 values in Caucasians are reported to be 500-1500 cells/mm³¹, whereas for Ethnical Chinese, sometimes lower normal values are reported (727 ± 255 cells/μl). These results are promising but a full analysis of the trial needs to be made.

12 December 2008. The man remains to be symptom free and has normalized CD4 count

1. Normal Values for CD4 and CD8 Lymphocyte Subsets in Healthy Chinese Adults from Shanghai
Weiming Jiang, Laiyi Kang, Hong-Zhou Lu, Xiaozhang Pan, Qingneng Lin, Qichao Pan, Yile Xue, Xinhua Weng, and Yi-Wei Tang

Effects of Coccinia indica and tolbutamide on human bloodsuger values

Pritsana Khamchaew, Edwin ten Winkel, bbPharma

Abstract. Coccinia indica (Climbing ivy gourd) is a herb used in traditional and Ayurvedic medicine in India where it is often combined with Abroma augusta.

100 patients with confirmed type II Diabetes mellitus were rondomized over two groups. One group received 2dd 200mg/kg of Coccinia indica (in watery extract, freeze dried and encapsulated), wheras the other group recieved Tolbutamide 2dd 200mg/kg. Treatment results were determined after 45 days.

Both Coccinia Indica and Tolbutamide caused a statistical and clinically significant lowering of bloodsuger values in comparison to base values. There were no statistically significant differences between patients treated with Coccinia Indica and patients treated with tolbutamide.

In vivo activity of NNRTI BBP153 against wildtype HIV-1

Pritsana Khamchaew, Edwin ten Winkel, bbPharma
BBP153, is shown to have potent in vitro activity, high genetic barrier to resistance development and favorable pharmacokinetics.

In Vitro Activity
BBP153, a new NNRTI, exhibits potent in vitro anti-HIV activity with an EC₅₀ against wild-type HIV-1 of 0.5 nM, and little or no loss of activity against HIV-1 variants having key NNRTI resistance mutations.

This might be a result of the adaptability of the interaction between BBP153 and the NNRTI binding site of HIV-1 reverse transcriptase which allows the compound to bind in different modes and adjust in case of RT mutations.

Male preputium eversion in Biomphalaria straminea caused by fluoxetine

Lam Hoi-ka, Edwin ten Winkel, bbPharma

Fluvoxamine (=Fluvox®), a selective serotonin reuptake inhibitor (SSRI) was tested for its ability to induce preputium eversion in Biomphalaria straminea in order to clarify the physiological mechanism of eversion. Biomphalaria straminea is a snail species that was accidentally introduced to Asia in recent years। Methioheptin and serotonin were added as controls. Fluvoxamine was found to have an MED of 10-50μM (p<0.0001). The receptor antagonist methiothepin was found to have an MED of 1 -10 μM (p <0.0001). Serotonin did not induce eversion and did not block methiothepin-induced eversion. This suggests that fluvoxamine is not acting as SSRI, but possibly as a receptor ligand.

Reference
Yapp, J.: Distribution of the Schistosome Vector Snail Biompholaria straminea: J. Mollus. Stud. 1990; 56: 47-55